tag:blogger.com,1999:blog-78806261137335370692024-02-21T05:25:50.950+00:00peterlandPeter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.comBlogger26125tag:blogger.com,1999:blog-7880626113733537069.post-72925418587922144312015-08-22T10:27:00.000+01:002015-08-22T10:34:56.231+01:00Getting the BMP085/BMP180 pressure sensor working with EMFCamp's Tilda MKe badge<span style="font-family: Arial,Helvetica,sans-serif;">So I've been looking at making something useful out of my <a href="https://wiki.emfcamp.org/wiki/TiLDA_MKe" target="_blank">Tilda MKe</a> badge from last years <a href="https://www.emfcamp.org/" target="_blank">EMF Camp</a> for some time now. With its nice (backlit) graphical LCD, I decided it'd be excellent to use as a temperature and atmospheric pressure display for my workshop at work. When you're calibrating <a href="https://www.topconpositioning.com/total-station-solutions/robotic-total-stations/ps-series" target="_blank">these</a> or <a href="http://www.leica-geosystems.co.uk/en/Leica-Viva-TS16_106677.htm" target="_blank">these</a> or <a href="http://www.trimble.com/Survey/Total-Station-S7.aspx" target="_blank">these</a>, you need to compensate for both to get an accurate distance measurement.</span><br />
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<span style="font-family: Arial,Helvetica,sans-serif;">I bought a <a href="http://www.ebay.co.uk/itm/121632682580" target="_blank">cheap as BMP180</a> sensor (it's a pin & software compatible updated version of the BMP085) from eBay for £1.19 and hooked it up to the first working Arduino I could find (which was about the third one I tried - really need to fix the others) and got out glorious pressure and temperature data over the serial port with the help of the <a href="https://github.com/adafruit/Adafruit-BMP085-Library" target="_blank">Adafruit library</a>.</span><br />
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<span style="font-family: Arial,Helvetica,sans-serif;">Great! Getting this going on the Tilda should be easy as. I knew from a bit of tinkering with the badge I did on site over the EMF Camp weekend that they were using an RTOS and they'd helpfully added a 'Hello World' app in the firmware for hacking purposes. I quickly modified the Hello World app to display the temperature.</span><br />
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<span style="font-family: Arial,Helvetica,sans-serif;">It didn't work.</span><br />
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<span style="font-family: Arial,Helvetica,sans-serif;">Huh. Somewhere in the back of my mind, I recalled that the Arduino Due (which the Tilda is based on) has two I2C interfaces. My first thought, confirmed by a quick look at the schematic, was that perhaps the Tilda's SDA and SCL pins that were brought out on the Arduino header weren't connected to the first I2C interface, which is what would be referred to when you normally use the wire library.</span><br />
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<span style="font-family: Arial,Helvetica,sans-serif;">No worries. I just had to modify the Adafruit library to use <span style="font-family: "Courier New", Courier, monospace;">wire1 <span style="font-family: Arial, Helvetica, sans-serif;">instead of <span style="font-family: "Courier New", Courier, monospace;">wire<span style="font-family: Arial, Helvetica, sans-serif;">. A bit of find/replace and I was getting </span></span></span></span>temperature data displayed on the LCD. Yay.</span><br />
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<span style="font-family: Arial,Helvetica,sans-serif;">From here, it should just be a case of adding in the call to read and display the pressure.</span><br />
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<span style="font-family: Arial,Helvetica,sans-serif;">It didn't work.</span><br />
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<span style="font-family: Arial,Helvetica,sans-serif;">But not in the way I had expected. I was geting some pressure data, but it was way, way too low. Like it thought I was up at 40,000m kind of atmospheric pressure.</span><br />
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<span style="font-family: Arial,Helvetica,sans-serif;">I spent a bit of time futzing about with various things. I knew it had to be related to the Tilda somehow so I looked into the RTOS and delved deep into the BMP085 datasheet. </span><br />
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<span style="font-family: Arial,Helvetica,sans-serif;">To measure the pressure with the BMP085 takes three steps:</span><br />
<ul>
<li><span style="font-family: Arial,Helvetica,sans-serif;">Firstly, each unit is individually calibrated at manufacture. The various calibration registers need to be read and their values saved for later calculations.</span></li>
<li><span style="font-family: Arial,Helvetica,sans-serif;">The pressure value is temperature sensitive as well, so the (uncompensated) temperature needs to be read from the chip and the true temperature calculated with the calibration data.</span></li>
<li><span style="font-family: Arial,Helvetica,sans-serif;">Lastly, read the uncompensated pressure value and, with the aid of the calibration data and the compensated temperature, you can go through a 15-step calculation to arrive at the correct pressure.</span></li>
</ul>
<span style="font-family: Arial,Helvetica,sans-serif;">I read in the datasheet that after requesting the pressure the chip can take up to 25ms for the ADC to convert the reading. I had a look in the Adafruit library:</span><br />
<blockquote class="tr_bq">
<span style="font-family: Arial,Helvetica,sans-serif;"><span style="font-family: "Courier New", Courier, monospace;"> if (oversampling == BMP085_ULTRALOWPOWER) <br /> delay(5);<br /> else if (oversampling == BMP085_STANDARD) <br /> delay(8);<br /> else if (oversampling == BMP085_HIGHRES) <br /> delay(14);<br /> else <br /> delay(26);</span></span></blockquote>
<span style="font-family: Arial, Helvetica, sans-serif;">I knew that doing this kind of blocking delay would stop background tasks in the RTOS from working so I changed them all to <span style="font-family: "Courier New", Courier, monospace;">Tilda::delay()<span style="font-family: Arial, Helvetica, sans-serif;"> as suggested, and crossed my fingers.</span></span></span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: "Courier New", Courier, monospace;"><span style="font-family: Arial, Helvetica, sans-serif;">It didn't work. I was getting a little bit annoyed at this point, so decided to take a little several week break.</span></span></span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: "Courier New", Courier, monospace;"><span style="font-family: Arial, Helvetica, sans-serif;">When I came back to it I continued looking at the way the Tilda was reading in the pressure data from the BMP085. Since the temperature was being calculated correctly it didn't point to an error in the calibration data or temperature reading.</span></span></span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: "Courier New", Courier, monospace;"><span style="font-family: Arial, Helvetica, sans-serif;">To confirm that it wasn't a hardware problem with my Tilda, I decided to try programming it <a href="https://wiki.emfcamp.org/wiki/TiLDA_MKe#Programming_the_badge_as_an_Arduino" target="_blank">as an Arduino</a> (ie, without the RTOS). Unfortunately, if you try this in the latest Arduino software (currently 1.6.4) you'll get a heap of errors like this:</span></span></span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: "Courier New", Courier, monospace;"><span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: "Courier New", Courier, monospace;">/home/peter/Downloads/Mk2-Firmware-master/hardware/emfcamp/sam/variants/tilda_mke_v0.333/variant.cpp:342:55: note: candidates are:<br />In file included from /home/peter/Downloads/Mk2-Firmware-master/hardware/emfcamp/sam/variants/tilda_mke_v0.333/variant.h:43:0,<br /> from /home/peter/Downloads/Mk2-Firmware-master/hardware/emfcamp/sam/variants/tilda_mke_v0.333/variant.cpp:24:<br />/home/peter/.arduino15/packages/arduino/hardware/sam/1.6.4/cores/arduino/UARTClass.h:45:5: note: UARTClass::UARTClass(Uart*, IRQn_Type, uint32_t, RingBuffer*, RingBuffer*)</span></span></span></span></blockquote>
<span style="font-family: Arial, Helvetica, sans-serif;">The easiest solution was to use an older version of Arduino. I had a guess at which one they'd used to write the Tilda software in the first place and picked version 1.5.7, which worked fine.</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;">I used the test sketch from the Adafruit BMP085 library (after modifying it to use <span style="font-family: "Courier New", Courier, monospace;">wire1<span style="font-family: Arial, Helvetica, sans-serif;"> again) and I was getting the correct temperature and pressure data out of the serial port!</span></span> </span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: "Courier New", Courier, monospace;"><span style="font-family: Arial, Helvetica, sans-serif;">Now I knew it wasn't a hardware problem, I needed to see the communication between the Tilda and the BMP180, and I had exactly the tool for the job, having recently acquired a <a href="http://www.rigol-uk.co.uk/Rigol-DS1054Z-Digital-Oscilloscope-p/ds1054z.htm" target="_blank">Rigol DS1054Z Oscilloscope</a>.</span></span></span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: "Courier New", Courier, monospace;"><span style="font-family: Arial, Helvetica, sans-serif;"><br /></span></span></span>
<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: "Courier New", Courier, monospace;"><span style="font-family: Arial, Helvetica, sans-serif;">I fired it up and was quickly able to probe the SCL (clock, top in yellow) and SDA (data, bottom in blue)</span></span></span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJIT6EPl1CKk28r8hsD8gIsVxr_rHf_3TQ0Z7ZJfInGMXYr4kze1VB7xqSUa8j7D9K0SBux1WwCGmWm2Tretf-hVUEjGCY0UwzCYhKTE-2CzFc-VgibSy6dAqiDvEB7ceWiCdD3Xs7ssU/s1600/DS1Z_QuickPrint6.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="384" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJIT6EPl1CKk28r8hsD8gIsVxr_rHf_3TQ0Z7ZJfInGMXYr4kze1VB7xqSUa8j7D9K0SBux1WwCGmWm2Tretf-hVUEjGCY0UwzCYhKTE-2CzFc-VgibSy6dAqiDvEB7ceWiCdD3Xs7ssU/s640/DS1Z_QuickPrint6.png" width="640" /></a></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">Zooming in on the last burst, we can use the DS1054's decode function to see what all these blips actually correspond to:</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrcFPb1jCXhvojNHig3TwGt5VKVZ0IZg56JFqLv70QEHElujwxZc2B-AI996KbGsWDML1BE_3-s0lFlPOvycoJNMTZhGhnCGN9RyQ25eNOhWm7VrbvQR7BlIfNOUufZxN0czeqYecwzNY/s1600/DS1Z_QuickPrint7.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="384" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgrcFPb1jCXhvojNHig3TwGt5VKVZ0IZg56JFqLv70QEHElujwxZc2B-AI996KbGsWDML1BE_3-s0lFlPOvycoJNMTZhGhnCGN9RyQ25eNOhWm7VrbvQR7BlIfNOUufZxN0czeqYecwzNY/s640/DS1Z_QuickPrint7.png" width="640" /></a></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">This is with the Tilda in Arduino mode - the data being read is 0xA26C20 (decimal 10644512). </span> <br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwGkv3AkcXLI8TxvKSMX2GaQhWNsJfFw9VlhqTCGsJvI2ALwWGkrln24WswJvUjVYUI3hc1AxBm5B0qFDCmqLQ6LwLt8ikYl3Y1JySZ5KlRqmq2lmD3lX2HmakrK0LjcuJTGztlyLRkvg/s1600/DS1Z_QuickPrint9.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="384" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwGkv3AkcXLI8TxvKSMX2GaQhWNsJfFw9VlhqTCGsJvI2ALwWGkrln24WswJvUjVYUI3hc1AxBm5B0qFDCmqLQ6LwLt8ikYl3Y1JySZ5KlRqmq2lmD3lX2HmakrK0LjcuJTGztlyLRkvg/s640/DS1Z_QuickPrint9.png" width="640" /></a></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">Here's with the Tilda back running my HelloWorld app in the RTOS. The data read here is 0xA277C0 (decimal 10647488). The difference is only about 0.03%. Surely not enough to account for my massive error.</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;">Obviously I was now going to have to delve into the calculations. Here's the page in the datasheet that describes the procedure:</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHpOhUyE01LbW_1uOJo5d4_jsdCYE2171YEOXBY81U_JvC-AIFXh_7-rbS7o3rwXvYS5gSjZ_B4u4XoEd1nMK8XAOWd1La90Gh45CGebuoYmQXt6YW2lWC3bwbwnr7E7WHejtwxc8uBfY/s1600/Screenshot+from+2015-08-22+09%253A39%253A02.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="473" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHpOhUyE01LbW_1uOJo5d4_jsdCYE2171YEOXBY81U_JvC-AIFXh_7-rbS7o3rwXvYS5gSjZ_B4u4XoEd1nMK8XAOWd1La90Gh45CGebuoYmQXt6YW2lWC3bwbwnr7E7WHejtwxc8uBfY/s640/Screenshot+from+2015-08-22+09%253A39%253A02.png" width="640" /></a></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">Err... that looks complicated. I ended up making a <a href="https://drive.google.com/file/d/0B2cd6b6ARDiKLUx5b0k4c2VBaHM/view?usp=sharing" target="_blank">spreadsheet </a>to help. I plugged both uncorrected pressure values into the spreadsheet and got consistent pressure values out. Well fuck. I was pretty sure now that the bug was somewhere deep in the RTOS and I really didn't think I was going to be able to find it. Unless.... </span><br />
<span style="font-family: Arial, Helvetica, sans-serif;"><br /></span>
<span style="font-family: Arial, Helvetica, sans-serif;">I'd been working on the assumption that the calibration data was being read ok because the temperature was being calculated correctly. However, after working through the calculation in my spreadsheet I knew that most of the calibration data doesn't get used until the pressure calculation.</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;">I got the Tilda to spit out the calibration data in both Arduino mode and the RTOS and lo and behold, the values for AC1 and AC5 differed markedly. I guessed that some background task in the RTOS was interfering with the read. I had a stab at fixing it by adding in a delay into the library:</span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;"><span style="font-family: "Courier New", Courier, monospace;"> Wire1.begin();<br /><br /> if (read8(0xD0) != 0x55) return false;<br /> <br /> Tilda::delay(5);<br /><br /> /* read calibration data */<br /> ac1 = read16(BMP085_CAL_AC1);<br /> ac2 = read16(BMP085_CAL_AC2);<br /> ac3 = read16(BMP085_CAL_AC3);<br /> ac4 = read16(BMP085_CAL_AC4);<br /> ac5 = read16(BMP085_CAL_AC5);<br /> ac6 = read16(BMP085_CAL_AC6);</span></span></blockquote>
<span style="font-family: Arial, Helvetica, sans-serif;">Which worked perfectly! All of that time and frustration was fixed by a 5ms delay in the right place, apparently. </span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgep1L9J8jTG9UIfJBSEi6cQZeyMClIMy2z3Umbub32j0wDQ3IMjvAbpb5jZA9VdbPnfRlUy4azI68h7dxTU0D_TKW5cNTJCRlO7Q_Ci9aymY24nXCDufzqt4njhB7PxI0C0i6d0wTTWJk/s1600/IMG_i67zay.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="476" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgep1L9J8jTG9UIfJBSEi6cQZeyMClIMy2z3Umbub32j0wDQ3IMjvAbpb5jZA9VdbPnfRlUy4azI68h7dxTU0D_TKW5cNTJCRlO7Q_Ci9aymY24nXCDufzqt4njhB7PxI0C0i6d0wTTWJk/s640/IMG_i67zay.jpg" width="640" /></a></div>
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<span style="font-family: Arial, Helvetica, sans-serif;">Niiiiiiiice! I'm not exactly convinced the temperature is 100% correct. It seems to be a couple of degrees warmer than I think it should be. The pressure looks to be correct though. </span><br />
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<span style="font-family: Arial, Helvetica, sans-serif;">Next time: Making it into a usable barometer.</span><br />
<span id="goog_1036762750"></span><span id="goog_1036762751"></span>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-21156396295407213522012-07-02T13:16:00.001+01:002012-07-02T13:16:48.744+01:00PCB Making<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiutMoOdoza0vJ3CTeFiKF2_x26QbR2vKyhpP5sGPtoZLKbCUQcT436wMoMDKg9PSGyJydvLlEEiaW1MVDHPTQQzMqz0agvre_0dv0_ZRTI3BdytC6H14G8Ueu5zLINozLj02-TtHTwyHA/s1600/P3253178.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiutMoOdoza0vJ3CTeFiKF2_x26QbR2vKyhpP5sGPtoZLKbCUQcT436wMoMDKg9PSGyJydvLlEEiaW1MVDHPTQQzMqz0agvre_0dv0_ZRTI3BdytC6H14G8Ueu5zLINozLj02-TtHTwyHA/s640/P3253178.JPG" width="640" /></a></div>
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I've been making a few PCBs recently with the toner transfer method with mixed results. This one turned out really well though. It's just a little adapter for changing the surface-mount connector for a 2*20 character LCD display to something a bit more breadboard friendly. Still haven't got around to actually using it though..</div>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com1Cardiff CF10 5FW, UK51.4655502 -3.170120551.4630772 -3.175056 51.468023200000005 -3.1651849999999997tag:blogger.com,1999:blog-7880626113733537069.post-37439712551085051712012-03-14T19:33:00.000+00:002012-03-14T19:33:17.906+00:00Big Muff clone completed<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi27y9m3OrIJPtM0UymC1f0qt_PZWZ4BFlpu_cX7bZNzBUHpkCfaueHFmu3QoYOBRCY-Ifn9jLkG6YKMHAI7fXA2LQ9nd90CDfum3cqLo5jF9l9nAi-fTDygcC3qBZE9s7sCRbr2_JSsO0/s1600/P3143171.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi27y9m3OrIJPtM0UymC1f0qt_PZWZ4BFlpu_cX7bZNzBUHpkCfaueHFmu3QoYOBRCY-Ifn9jLkG6YKMHAI7fXA2LQ9nd90CDfum3cqLo5jF9l9nAi-fTDygcC3qBZE9s7sCRbr2_JSsO0/s640/P3143171.JPG" width="640" /></a></div>
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I've finished my clone of the well-known Big Muff distortion pedal. I painted it with some grey primer and then with a design of <a href="http://maps.google.co.uk/maps?q=cardiff&hl=en&ll=51.456414,-3.169041&spn=0.03011,0.077162&sll=51.456788,-3.169813&sspn=0.03011,0.077162&gl=uk&hnear=Cardiff,+United+Kingdom&t=m&z=14" target="_blank">Cardiff Bay</a> as I have a vague notion of making myself a range of Cardiff-themed effect pedals. Total cost in parts was around £16-17 and a lot of that is because I bought the extortionately expensive switch from Maplin instead of pretty much anywhere else.</div>
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It sounds quite a lot like the original as far as I can tell. It is REALLY LOUD, and is unfortunately not very useful for playing in our apartment as I get the feeling I must be annoying the hell out of the neighbours, even at low volumes.</div>
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Next up will be a Small Clone clone. A clone<sup>2</sup> I guess. It's a chorus pedal that was used by Kurt Cobain on <i>Nevermind</i> apparently. I've ordered up the parts from far-flung ebay sellers across East Asia, so they'll take at least a couple of weeks to get here, which gives me plenty of time to change my mind and start and abandon another several projects.</div>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com2tag:blogger.com,1999:blog-7880626113733537069.post-61254047465804926292012-03-11T16:25:00.000+00:002012-03-11T16:25:17.402+00:00Big Muff clone<div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;">
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This weekend I've been down at <a href="http://cardiff.hackspace.org.uk/wiki/Main_Page" target="_blank">Cardiff Hackspace</a> building a clone of the well known <a href="http://en.wikipedia.org/wiki/Big_Muff" target="_blank">Big Muff</a> distortion pedal, first getting it working on a solderless breadboard:</div>
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Then I built it on some copper stripboard, but for some reason couldn't get it working. After checking, rechecking and re-rechecking, I finally spotted the problem:</div>
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See the problem? No?</div>
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There it goes - at one of the points where I'd used a drill bit to break the copper track I hadn't quite broken it completely. Those holes are 2.54mm apart so the bit of copper that was left couldn't have been much more than 0.2mm wide, but it was enough for electrons to squeeze through and stop it producing any sound.</div>
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Once that and several other problems were sorted, I brought it home and tried it out. It doesn't sound exactly like the original, but it has a nice tone with loads of gain. Hopefully this week I'll put it in a nice enclosure.</div>
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<br /></div>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-42475028903817884942012-03-03T10:04:00.000+00:002012-03-03T18:46:13.235+00:00Soldering iron power LED<div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;">
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For xmas a couple of years ago my parents bought me a nice temperature-controlled soldering station which I've been using to build all my half-completed projects. It works great, but it has one small problem: the LCD display isn't backlit so, at a glance, it isn't obvious that the power is on. This isn't normally a problem but if I'm working on something that means I'm soldering something and then going back and forward to the computer to program an Arduino or whatever, it's possible to forget the soldering iron is on.</div>
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And then go to bed.</div>
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And then go to work.</div>
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And then come home and find out that there's been a 50W desk-mounted heater on for 24 hours and somehow we still have a home and not a smouldering ruin.</div>
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The solution to this problem is trivially easy - mount an LED on the front to make it obvious that the iron's on. First thing we need to do is open up the soldering iron and find a power source to hook our LED up to.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjalCqmht6Ow_SOxnH3aCq05uhedXhpkVR5dOI-feZZ9J86YeWLyY3IQxJEcUwAfzSa-cwoTUgiuUh_DzHrUY20etLBzKKx4fFsx2BlFjeXzrrZERg_Sg27RAuvqgjPkRjaxE9lFfzrlWU/s1600/P3033156.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjalCqmht6Ow_SOxnH3aCq05uhedXhpkVR5dOI-feZZ9J86YeWLyY3IQxJEcUwAfzSa-cwoTUgiuUh_DzHrUY20etLBzKKx4fFsx2BlFjeXzrrZERg_Sg27RAuvqgjPkRjaxE9lFfzrlWU/s640/P3033156.JPG" width="640" /></a></div>
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This is the main PCB for the iron, and at the top left is an LM7805 linear voltage regulator that supplies the 5v to power the control circuity. Perfect and has long leads that we can solder to. If you're looking at the front of the LM7805, the three leads are Vin - GND - Vout.</div>
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A quick check with the multimeter to confirm. </div>
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I come to a small problem here - how am I going to solder on the inside of my soldering iron? I briefly consider using the soldering iron itself and then remember that I have a butane powered soldering iron for just these sorts of occasions:</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiy-qHGYb7OoMm7n4DzEDzzjEOi01EWn5UNd3YrWCvfJIFN2qy7Z9o8-MYME03AI0NACXoJhMcZqCbcjj-OPRGhunKKsiEXWE3regjytqRx6-5kmb1WWcTCHbNzfPHkjVvkFMkeUQYOVjc/s1600/P3033158.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiy-qHGYb7OoMm7n4DzEDzzjEOi01EWn5UNd3YrWCvfJIFN2qy7Z9o8-MYME03AI0NACXoJhMcZqCbcjj-OPRGhunKKsiEXWE3regjytqRx6-5kmb1WWcTCHbNzfPHkjVvkFMkeUQYOVjc/s640/P3033158.JPG" width="640" /></a></div>
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I dig out a 5mm red LED and find my <a href="http://www.evilmadscientist.com/article.php/ledcalc" target="_blank">LED calculator</a> to work out what current limiting resistor I need. Looks like 150 ohms will do the trick, which is one of the several values I have. 10 minutes and some dremel action later and we have this:</div>
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I should have used some heatshrink, but I couldn't find any. It should be ok like this though. The LED fits in pretty snugly but for peace of mind I might stick some hot glue on the back to hold it in. But does it work...?</div>
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<tr><td class="tr-caption" style="text-align: center;">Power off</td></tr>
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Success! And all done before breakfast on a Saturday. Quite good fun in the end, and if it stops me from accidentally burning down the house, well that's just a bonus.</div>
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<br /></div>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com3tag:blogger.com,1999:blog-7880626113733537069.post-9915966333732359842012-02-29T17:00:00.000+00:002012-03-02T22:49:08.496+00:00Skittle sorting<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYRMmaWpIUfgsLywfx5sgNqxsqC1znW0kDTqV0z60OEw8j1xAX8IN8PiuWHWdGsekSJj1kHpqzaeqpqpWV5D8qk8zUshdkKQLz-XVrma3HG7vWXClsBzbdAVUq343lssFCZYbzkwcsYuY/s1600/P6201987.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYRMmaWpIUfgsLywfx5sgNqxsqC1znW0kDTqV0z60OEw8j1xAX8IN8PiuWHWdGsekSJj1kHpqzaeqpqpWV5D8qk8zUshdkKQLz-XVrma3HG7vWXClsBzbdAVUq343lssFCZYbzkwcsYuY/s640/P6201987.JPG" width="480" /></a></div>
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Extremely important Skittle sorting prior to making Skittle vodka, which was amazingly tasty and alarmingly drinkable. Especially the orange flavour. We passed the cheap and nasty vodka through a Brita charcoal filter before infusing it with the Skittles, which I think made a bit of a difference. It certainly made a difference to our filtered water for the next couple of weeks as it had a bit of a vodka flavour until we got around to changing the filter.</div>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com1tag:blogger.com,1999:blog-7880626113733537069.post-63216819096715386172012-02-29T10:52:00.000+00:002012-02-29T10:52:19.209+00:00Oscilloscopes<div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;">
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This is a nice 20MHz analog scope that was donated by UWIC to Cardiff Hackspace. It's awesomely retro but works great. I don't know how I ever managed to do any electronics without access to an oscilloscope. I keep meaning to use it to display some graphics. I even got around to getting some DACs (Digital to Analog Converters):</div>
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Yeah, soldering that onto the breakout board was quite tricky. The main body of the chip (the black bit) is only 1.75 by 1.3mm big. I haven't got around to doing any more than that, so it's in the pile of ideas and half-completed projects.</div>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-62816724366107181162012-02-28T20:35:00.000+00:002012-02-28T20:35:00.148+00:00Fire is the Purifier<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjB42I74rYj7NdoNt5fPEwVdbMeSihWOUZJljDTTs__v9r2iqcZOfZIZ3owHgY9Vdeqvuvxj3BRvoFLqYn3gqSDOMd5DHzbtTda-5glT58X6LpiE_TBvnbulfrZSySzacRVXHvCZAZjfhc/s1600/P5301834.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjB42I74rYj7NdoNt5fPEwVdbMeSihWOUZJljDTTs__v9r2iqcZOfZIZ3owHgY9Vdeqvuvxj3BRvoFLqYn3gqSDOMd5DHzbtTda-5glT58X6LpiE_TBvnbulfrZSySzacRVXHvCZAZjfhc/s640/P5301834.JPG" width="640" /></a></div>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-24033530019754052012-02-28T10:06:00.001+00:002012-02-28T10:06:00.719+00:00LED forest<div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuZjar1UN5XijvGg7ct_nq72ul-0x7gzTxLMlkSFEXc2dlNQP9JgbIGkbgYZWyKRyU_Xf3F3JZcxMgv2YuFVUNcbGD8i3bkVCagsp8SG23mKrl5vkJZ8ebYIYWyOZfYhhJYAlu7iQFgeQ/s1600/PB182945.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuZjar1UN5XijvGg7ct_nq72ul-0x7gzTxLMlkSFEXc2dlNQP9JgbIGkbgYZWyKRyU_Xf3F3JZcxMgv2YuFVUNcbGD8i3bkVCagsp8SG23mKrl5vkJZ8ebYIYWyOZfYhhJYAlu7iQFgeQ/s640/PB182945.JPG" width="480" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"> Yes, that is quite a lot of LEDs. I did this for a test of my still-in-progress sunrise alarm clock that I started back in October and now will almost certainly not get around to finishing before winter is over rendering the whole thing completely unnecessary.</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmkz5ipRH9ispt3kGugQ2dWcLF-M_ox4XBw8Bw9guxX2UCIyDMSrtw5H701-sd5IeAQew5rB-RWsKoDTgtov_RdzyMqY878D0FQqtx3mCAYcOWwHnwly1o9F_1biyHGwueNwmmGVH0F90/s1600/PB182947.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmkz5ipRH9ispt3kGugQ2dWcLF-M_ox4XBw8Bw9guxX2UCIyDMSrtw5H701-sd5IeAQew5rB-RWsKoDTgtov_RdzyMqY878D0FQqtx3mCAYcOWwHnwly1o9F_1biyHGwueNwmmGVH0F90/s640/PB182947.JPG" width="640" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">Ahh, but it looks so pretty.</div>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com2tag:blogger.com,1999:blog-7880626113733537069.post-14817895345633577282012-02-27T23:08:00.000+00:002012-02-27T23:08:20.752+00:00Allotment shed building<div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzQABq6chJ9uBXJ1lTWuEeW5f-y5GDgrXPMb7fJNHDrjFCvXcDDg7_HgkrbPl59yUzflmee8-SENzmBIgzyXivNk85XZf_KPwuErmYXUecAse-j2auKE74pMETnZdJ74hXoqkdGR5T_LI/s1600/P2273149.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzQABq6chJ9uBXJ1lTWuEeW5f-y5GDgrXPMb7fJNHDrjFCvXcDDg7_HgkrbPl59yUzflmee8-SENzmBIgzyXivNk85XZf_KPwuErmYXUecAse-j2auKE74pMETnZdJ74hXoqkdGR5T_LI/s640/P2273149.JPG" width="640" /></a></div>
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This is our amazingly spectacularly awesome almost finished shed we've built on our allotment. Hewn from a pile of pallets, scrap plywood and doors, with bonus store damaged roof sheeting from B&Q. Doors make remarkably good walls, so we're not expecting to have to replace this in the near future. </div>
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This is the largest structure I've ever built, easily overtaking my tree house that I built from 1993-97. I have not yet broken any bones in the construction of this though. I really should scan some of my x-rays sometime....</div>
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Anyway, we now (well, ironically, when we put a door on it) have somewhere to store all our tools and various other bits of gardening equipment that we've accumulated already.</div>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0Bessemer Rd, Cardiff, South Glamorgan CF11 8BA, UK51.4681614 -3.198791851.4656884 -3.2037273 51.4706344 -3.1938562999999998tag:blogger.com,1999:blog-7880626113733537069.post-41241483182292147582012-02-27T19:58:00.000+00:002012-02-27T19:58:00.453+00:00Allotment surprises<div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhW5zVbvpStsT1wrTp0F23PlYo0tTJzmeTZM9MBdIZSHTOMw46HUgJlI5JOAA0z2Bt_ZRrMWY4W9yWaaxIyYMG6R_nN2XSqw5f_McztZRtpD15VkPkAt0aY_96r27wdE3GQAQrqLqmlGog/s1600/PB142942.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhW5zVbvpStsT1wrTp0F23PlYo0tTJzmeTZM9MBdIZSHTOMw46HUgJlI5JOAA0z2Bt_ZRrMWY4W9yWaaxIyYMG6R_nN2XSqw5f_McztZRtpD15VkPkAt0aY_96r27wdE3GQAQrqLqmlGog/s640/PB142942.JPG" width="640" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">So when you pick nice fresh food from your allotment (or, in this case, my Dad's) you should remember that slugs are really good at hiding. This one only made its appearance after a day in the fridge, which was <b>quite </b>surprising.</div>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-4620287691863190832012-02-27T10:39:00.004+00:002012-02-27T10:39:00.130+00:00Reprap Heated Bed Testing<div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"></div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"></div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWAYDusssHxU8roaG2_ITmWkdikGvPHGOI-6EfM6Jk13BUUGb6Ff0cDY1bEiATK7zwzgQm7bHuEmMW3xqJtpZ8WKaSoF1UHsRCPaypUoGvYx0OdoVKQCok5v1Tznh68Czj4l74NmUmxiU/s1600/PC072975.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWAYDusssHxU8roaG2_ITmWkdikGvPHGOI-6EfM6Jk13BUUGb6Ff0cDY1bEiATK7zwzgQm7bHuEmMW3xqJtpZ8WKaSoF1UHsRCPaypUoGvYx0OdoVKQCok5v1Tznh68Czj4l74NmUmxiU/s640/PC072975.JPG" width="640" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"> This is the heated printbed from <a href="https://twitter.com/#%21/IainATweets" target="_blank">Iain</a>'s reprap being tested after he'd replaced the nichrome wire based heater with some chunky high powered resistors:</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-b3y9mVJbzdVauKd0xU3PIfzaHk3MZwxo8l8uZ1Hh1ee2MgWdQ0ZBODsGl73FhQ_1IwhPbGslZZzp76mNdWSOtLXXB8LeASIJ-MW8MH7PMDLcyu47t0Okj0x79X5eyL39tQTOMYxl9Yw/s1600/PC072978.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-b3y9mVJbzdVauKd0xU3PIfzaHk3MZwxo8l8uZ1Hh1ee2MgWdQ0ZBODsGl73FhQ_1IwhPbGslZZzp76mNdWSOtLXXB8LeASIJ-MW8MH7PMDLcyu47t0Okj0x79X5eyL39tQTOMYxl9Yw/s640/PC072978.JPG" width="640" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">Once all soldered together and attached to the build platform with metalised epoxy, we fired it up and checked it out with a thermal imaging camera graciously loaned by my work:</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiD5wZMBoaphWhoPxwN2EGqWH61q6fsKd-sGQ2LE2gZCeEfs6vidxXB-IrJzLEZ0WYdjafTGtdAHenPqdCb2wkA0wPZZTEC9gXunurPez3jELzAi56otQv1UlE9289DdXs8l_7m9SQnNv0/s1600/PC072976.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiD5wZMBoaphWhoPxwN2EGqWH61q6fsKd-sGQ2LE2gZCeEfs6vidxXB-IrJzLEZ0WYdjafTGtdAHenPqdCb2wkA0wPZZTEC9gXunurPez3jELzAi56otQv1UlE9289DdXs8l_7m9SQnNv0/s640/PC072976.JPG" width="640" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">Interestingly, the parts where there isn't any Kapton tape show up as much cooler - not because they are any cooler but because the bare metal is reflecting an IR image of the cold window. Anyway, the heater seems to work pretty well as Iain's reprap is churning out all sorts of interesting stuff. </div>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-34797307075331384932012-02-26T19:36:00.000+00:002012-02-26T19:36:22.762+00:00Mintyboost clone<div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixDUZWKpp8EcJYTME4Dcs_JFiNbT4VZMag8QVG8Jov7o6sRRQeYhvkR_VtiK9o_8cT_OKvEDhytF71BVBdFJAPD6ge44i_SQ4-pqw1vVRIv226u92ipb75qUkH3RmpNjtQVIUzU_cHK_g/s1600/P1033071.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixDUZWKpp8EcJYTME4Dcs_JFiNbT4VZMag8QVG8Jov7o6sRRQeYhvkR_VtiK9o_8cT_OKvEDhytF71BVBdFJAPD6ge44i_SQ4-pqw1vVRIv226u92ipb75qUkH3RmpNjtQVIUzU_cHK_g/s640/P1033071.JPG" width="640" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">This is a clone of Adafruit's <a href="http://www.ladyada.net/make/mintyboost/" target="_blank">Mintyboost</a> that I made to take to Glastonbury last year to keep my phone charged. It's basically the suggested schematic and layout from the LT1302 step-up converter. It turned out pretty well - I like that its not much bigger than the two AA cells it runs on. Could do with a nice 3D printed case for the component side perhaps.</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">Performance wise, it was a bit disappointing. I think that was quite a lot to do with the crappy batteries we took with us and that were available on the site. I didn't actually test it very much. At some point, I'll get around to doing a proper test with various batteries.</div>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-77718746702260682802012-02-26T09:48:00.000+00:002012-02-26T09:48:51.551+00:00Tree Rabbit<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXJRBzbzQUlzTGaitwyAOCWYp-JzUi8H4dWEKpReEh1SpG4yadSshrnTAPZ-pkzk4fzNye8R0wgkVxM7PCjBY_12GpIkgB7d9NaJabT3jpVjg2WfkfLa56GpVyTpG-spaqdv495ebqDis/s1600/PB272957.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXJRBzbzQUlzTGaitwyAOCWYp-JzUi8H4dWEKpReEh1SpG4yadSshrnTAPZ-pkzk4fzNye8R0wgkVxM7PCjBY_12GpIkgB7d9NaJabT3jpVjg2WfkfLa56GpVyTpG-spaqdv495ebqDis/s640/PB272957.JPG" width="480" /></a></div><span style="font-family: Arial,Helvetica,sans-serif;">Got this squirrel at the farmers market and later made a very tasty casserole from it. Not a huge amount of meat on it but has a good flavour.</span>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-17808325903152513902012-02-25T22:25:00.001+00:002012-02-26T18:28:02.275+00:00<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKDqiAe37Ps5tQbWNTeYmi7m_pc5tkLEUTCq2JQxaBuKkm3yBwqY50D-Wqz_2cZIi9-Ldc7fURGSYkhjsUMRau6LLEHakBtEP73OYIByFkqOnzYnHwonoXSQ4NvYdr44kz1yT05cib-_A/s1600/PA232898.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKDqiAe37Ps5tQbWNTeYmi7m_pc5tkLEUTCq2JQxaBuKkm3yBwqY50D-Wqz_2cZIi9-Ldc7fURGSYkhjsUMRau6LLEHakBtEP73OYIByFkqOnzYnHwonoXSQ4NvYdr44kz1yT05cib-_A/s640/PA232898.JPG" width="480" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;">I would be a terrible mime.</div>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-14236935384935650722012-02-24T19:37:00.000+00:002012-02-24T19:37:36.948+00:00<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjOh_PptrGwyip9JZKkAZBZDKslUQyPetUdrbMytC1qioL8U3MD25x_orPUsAeqrEZWhWGzwh-7TvP4jRGEaK4OLxMYzdzpyTN0mJFtO_5dqukiq-EMe3qIkMF6U60jbglnIVb6sLq-q9Y/s1600/P2193127.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjOh_PptrGwyip9JZKkAZBZDKslUQyPetUdrbMytC1qioL8U3MD25x_orPUsAeqrEZWhWGzwh-7TvP4jRGEaK4OLxMYzdzpyTN0mJFtO_5dqukiq-EMe3qIkMF6U60jbglnIVb6sLq-q9Y/s640/P2193127.JPG" width="640" /></a></div><br />
<span style="font-family: Arial,Helvetica,sans-serif;">Unnecessarily robust reclaimed pallet-wood table, built for our allotment. </span>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-41026473715573636362012-02-23T20:13:00.001+00:002012-02-26T09:49:29.973+00:00<div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5P5xtoVTTLBtzCinRRXJGZaA2ZxYUPWbr5Jzq6d7S6OFtBzzAPQlQ6F2wYsKWC_vVafWzlwp3Z1xH1bpEb2X8LkoU0CljX7zkL6cM-W4sOSk0GrOcECjpNVrLtCqDtQW2KeLSJL14KiM/s1600/2010-12-29+16.41.16.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5P5xtoVTTLBtzCinRRXJGZaA2ZxYUPWbr5Jzq6d7S6OFtBzzAPQlQ6F2wYsKWC_vVafWzlwp3Z1xH1bpEb2X8LkoU0CljX7zkL6cM-W4sOSk0GrOcECjpNVrLtCqDtQW2KeLSJL14KiM/s640/2010-12-29+16.41.16.jpg" width="640" /> </a></div><div class="separator" style="clear: both; text-align: left;"><br />
</div><div class="separator" style="clear: both; text-align: left;"><span style="font-family: Arial,Helvetica,sans-serif;">Optimal use of frying pan space when making fish finger and black pudding sandwiches.</span> </div><span id="goog_804356014"></span><span id="goog_804356015"></span>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-31854141340416931252012-02-23T13:26:00.001+00:002012-02-24T21:51:22.148+00:00Replacement beer fridge thermostat<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOhBzL7eo1ekdWFCxULdK-5hDqtpldsnkqKXGTDMoTqxsOzd5Z8Z4J9KnOhGpGvcg_49-_7i0187G5tIsxh6TkUVwsXVDIWMCFUuizVF_HfC-9m5IioCnF1hn3bRQ0Gk481CeQBw74vto/s1600/PB082935.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOhBzL7eo1ekdWFCxULdK-5hDqtpldsnkqKXGTDMoTqxsOzd5Z8Z4J9KnOhGpGvcg_49-_7i0187G5tIsxh6TkUVwsXVDIWMCFUuizVF_HfC-9m5IioCnF1hn3bRQ0Gk481CeQBw74vto/s640/PB082935.JPG" width="640" /></a></div><br />
<span style="font-family: Arial,Helvetica,sans-serif;">This is an Arduino-based thermostat I made for the <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi0qpLrQp5Om2IQT5LSn_tGjLidTWXW3DsJhy66VOwC_9qZnihSDRG0Kkp1XRN2CuCIsa1NvF_5xA5Htm5Gfj_hHOocLSPkjK9e9n3LbjZpCOiyoG_oFLcSqJLyxOOX15Hj9HAncyG-gqU/s903/2010-09-10+17.36.52.jpg" target="_blank">beer fridge</a> that Tina found in the rubbish outside our flat. It worked fine for a few months and then stopped - the mechanical thermostat had crapped out.</span><br />
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<span style="font-family: Arial,Helvetica,sans-serif;">Coincidentally, I had a thermocouple and a MAX6675 thermocouple amplifier hanging around that I'd purchased with my Sparkfun free day winnings so I threw this together and installed it into the space where the old thermostat had been. Since I had heaps of I/O pins left I added a 7-segment display to display the temperature on the front of the fridge.</span><br />
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<span style="font-family: Arial,Helvetica,sans-serif;">It works great, and is currently installed at <a href="http://cardiff.hackspace.org.uk/wiki/Main_Page" target="_blank">Cardiff Hackspace</a>, cooling our beers. </span>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com10tag:blogger.com,1999:blog-7880626113733537069.post-63922874117669170172012-02-22T21:04:00.000+00:002012-02-22T21:04:00.730+00:00<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqMsz7C1ZnmQTkjUtzi1SsO7-OkpQsmuMkS76TfeXaDp6K4C2zIMff4kjElPXEtluorEX537E4h1p7YT5xXNBk9aY2rfBizvVimBzEzbEWC4T8qpk2Mj47L2G54-vAg8aXIbocKjOGzFY/s1600/IMG_4577.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqMsz7C1ZnmQTkjUtzi1SsO7-OkpQsmuMkS76TfeXaDp6K4C2zIMff4kjElPXEtluorEX537E4h1p7YT5xXNBk9aY2rfBizvVimBzEzbEWC4T8qpk2Mj47L2G54-vAg8aXIbocKjOGzFY/s640/IMG_4577.JPG" width="640" /></a></div><br />
<span style="font-family: Arial,Helvetica,sans-serif;">Kittehs love books</span>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-74492589444171516592012-02-19T22:57:00.000+00:002012-02-19T22:57:18.310+00:00<div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJm2Qg9yjROYl0UfXem_fjotQ3RLkJtBVtK6Er7kl9yHjPZOU5jeQ_SnhM9UvTlfp0RemZ4ZIga0JqlxwzGCSvahoUAGkm_StTkNoESjR74RZb8UxDc3tvlj-h-SPrz1-D1z_qCvT7YmA/s1600/P2183124.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="480" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJm2Qg9yjROYl0UfXem_fjotQ3RLkJtBVtK6Er7kl9yHjPZOU5jeQ_SnhM9UvTlfp0RemZ4ZIga0JqlxwzGCSvahoUAGkm_StTkNoESjR74RZb8UxDc3tvlj-h-SPrz1-D1z_qCvT7YmA/s640/P2183124.JPG" width="640" /></a></div><br />
<span style="font-family: Arial,Helvetica,sans-serif;">Nice scope trails.</span>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-21150553048846299872011-04-11T20:06:00.000+01:002011-04-11T20:06:56.194+01:00Lithium Ion battery (near) disaster<div style="font-family: Arial,Helvetica,sans-serif;">Lithium Ion battery failures are well documented. There were have been many fires and explosions and Sony recalled millions of laptop batteries in 2008.<br />
<br />
My phone battery has been getting steadily worse and today on my way to our Bristol branch for some training my phone turned off even though it had been fully charged an hour before.<br />
<br />
I took out the battery to reset it and immediately noticed a distinct bulge in the middle of the battery. Here's a picture of the measurement across the middle of the replacement battery that I've had for months but not got around to putting in:</div><br />
<div style="text-align: center;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgd0DtHC4PXAMTPhJ_OCGO1IJ8_UXYx4PwbZM8zX8aOKN5kEXaltdn1EM_3lpSujHybRKc8Z5lPz-VIgM_1nGncFYHkeMvxlaVhEsH2L9CspLqHWf_T7Ei_zITHts17Xn7Q_3EJ00Z-J2w/s320/P4110309.JPG" width="320" /> </div><div style="text-align: center;"><br />
</div><div style="text-align: left;"><span style="font-family: Arial,Helvetica,sans-serif;">And the old one:</span> </div><br />
<div style="text-align: center;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg0wjiUv1Qx7ys2R3FTuESj_00o1dxSfxUT6DyyztkEIQrwJfPH8UlQ_uQqP7swVWF1zTEtndd1xXnZJ0pmQ6mTj5TgragoBG80hrlxWFlWfwbK3TF59D2PqbAxgnh2ad5D80l08puV4P0/s320/P4110310.JPG" width="320" /> </div><div style="text-align: center;"><br />
</div><div style="text-align: left;"> <span style="font-family: Arial,Helvetica,sans-serif;">Given that this is often the first sign of failure, and that the next sign is failure tends a bit on the firey side, I might just throw this battery away.</span> </div>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com1tag:blogger.com,1999:blog-7880626113733537069.post-71201390033266316452010-03-09T21:40:00.000+00:002010-03-09T21:40:58.658+00:00Wild Wales<span style="font-family: Arial,Helvetica,sans-serif;">I've just finished reading Wild Wales, by George Borrow, which I picked up in an Oxfam bookshop for £4.99, not long after we moved over here. I know this because I've been using a train ticket (Day Travelcard between Earlsfield and zones 1,2,3 and 4; dated 22 October 2006) as my bookmark, which is quite convenient.</span><br />
<span style="font-family: Arial,Helvetica,sans-serif;"> </span><br />
<span style="font-family: Arial,Helvetica,sans-serif;">The book, first published in 1862, is a telling of Borrow's (mostly) walking tour of Wales, in 1854. He starts off in the north and covers much of the country, inexplicably missing out most of Carmarthenshire and all of Pembrokeshire as well as Cardiff.</span><br />
<span style="font-family: Arial,Helvetica,sans-serif;">I won't give a full review, but it is an interesting look at Wales, right at the beginning of its industrial boom. I particularly appreciate this passage, describing his arrival at Merthyr Tydfil at night, at a time when (I believe) my great-great-great-grandfather, Thomas Hughes, was living there:</span><br />
<blockquote><div style="font-family: Arial,Helvetica,sans-serif;">Turning round a corner at the top of a hill I saw blazes here and there, and what appeared to be a glowing mountain in the south-east. I went towards it down a descent which continued for a long, long way; so great was the light cast by the blazes and that wonderful glowing object, that I could distinctly see the little stones upon the road. After walking about half-an-hour, always going downwards, I saw a house on my left hand and heard a noise of water opposite to it. It was a pistyll. I went to it, drank greedily, and then hurried on. More and more blazes, and the glowing object looking more terrible than ever. It was now above me at some distance to the left, and I could see that it was an immense quantity of heated matter like lava, occupying the upper and middle parts of a hill, and descending here and there almost to the bottom in a zigzag and tortuous manner. Between me and the hill of the burning object lay a deep ravine. After a time I came to a house, against the door of which a man was leaning. “What is all that burning stuff above, my friend?”</div><div style="font-family: Arial,Helvetica,sans-serif;">“Dross from the iron forges, sir!”</div><div style="font-family: Arial,Helvetica,sans-serif;">I now perceived a valley below me full of lights, and descending reached houses and a tramway. I had blazes now all around me. I went through a filthy slough, over a bridge, and up a street, from which dirty lanes branched off on either side, passed throngs of savage-looking people talking clamorously, shrank from addressing any of them, and finally, undirected, found myself before the Castle Inn at Merthyr Tydvil.</div></blockquote><span style="font-family: Arial,Helvetica,sans-serif;">Delightful.</span>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-83117434546810558572010-02-22T20:49:00.001+00:002012-02-26T09:49:12.789+00:00GPS: Working! (well, nearly)<span style="font-family: Arial,Helvetica,sans-serif;">So I got my GPS module working.. sort of. After stuffing around with it for ages it turns out I was just being daft, and after fixing several obvious problems in both hardware and software I was getting lovely NMEA codes out:</span><br />
<blockquote><span style="font-family: Arial,Helvetica,sans-serif;">$GPGGA,202429.009,0000.0000,N,00000.0000,E,0,00,0.0,0.0,M,,,,0000*08 <br />
$GPGSV,3,1,12,27,89,000,33,16,66,000,,15,54,000,,25,50,000,*7C <br />
$GPGSV,3,2,12,14,31,000,,19,28,000,,13,24,000,,17,21,000,*7F <br />
$GPGSV,3,3,12,23,18,000,,05,08,000,,29,01,000,,02,-2,000,*68 </span></blockquote><span style="font-family: Arial,Helvetica,sans-serif;">The $GPGGA line is positioning data and the $GPGSV lines are data about the satellites we can see. Unfortunately from the flat we don't have enough sky view to be able to get a fix. The GPS is only tracking one satellite which is only good enough to give us the current time as shown in the first line (20:24:29).</span><br />
<br />
<span style="font-family: Arial,Helvetica,sans-serif;">Next plan is to write some software to do something useful with the data... </span>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-90850308620308380972010-02-17T21:40:00.002+00:002012-02-26T09:49:48.554+00:00Homemade Toner transfer PCBs<span style="font-family: Arial,Helvetica,sans-serif;">We've just recently bought a laser printer so I've been trying to make some decent printed circuit boards with the toner transfer method, where you take a reversed printout of your circuit and iron it on to plain copper-clad board, then etch the board and the toner resists the etchant, and the circuit remains in copper on the board.</span><br />
<br />
<span style="font-family: Arial,Helvetica,sans-serif;">That's the theory anyway, but finding the right paper is a problem. You need a glossy, waxy paper that will easily come away from the toner when you are done ironing, but most papers just fall apart and you are stuck with half a sheet of paper firmly attached to your circuit-board-to-be.</span><br />
<br />
<span style="font-family: Arial,Helvetica,sans-serif;">Many people on the internet seem to use magazine pages, but I have found them to be uniformly rubbish for fine-pitched traces. </span><br />
<br />
<span style="font-family: Arial,Helvetica,sans-serif;">For future reference, the following papers don't work:</span><br />
<br />
<span style="font-family: Arial,Helvetica,sans-serif;">Buzz (Cardiff gig guide)</span><br />
<span style="font-family: Arial,Helvetica,sans-serif;">Guardian Weekend Magazine</span><br />
<span style="font-family: Arial,Helvetica,sans-serif;">New Scientist</span><br />
<span style="font-family: Arial,Helvetica,sans-serif;">Look Magazine</span><br />
<span style="font-family: Arial,Helvetica,sans-serif;">Cotswolds catalogue</span><br />
<span style="font-family: Arial,Helvetica,sans-serif;">Domino's Flyer.</span><br />
<span style="font-family: Arial,Helvetica,sans-serif;">Tesco "Value" glossy photo paper</span><br />
<span style="font-family: Arial,Helvetica,sans-serif;">and regular Kitchen Paper, which I thought would work well, but doesn't seem to want to release the toner onto the copper.</span>Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0tag:blogger.com,1999:blog-7880626113733537069.post-85395109447996434482009-11-14T08:15:00.001+00:002009-11-14T08:15:14.992+00:00LiverpoolSo we're on our way to Liverpool for the weekend. Once again, it's a bit of a spur of the moment plan. I like to think that we're decisive instead of impulsive...<br /><br />Anyway, we're hoping to see a Bridget Riley exhibition while we're there. I saw some stuff of hers in Wellington in 2005 and it's pretty awesome. It's all crazy geometic patterns that mess with your eyes. Unfortunately last time I was quite hungover and it wasn't the best.Peter Tangneyhttp://www.blogger.com/profile/01441497484461543520noreply@blogger.com0