Monday 2 July 2012

PCB Making

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..

Wednesday 14 March 2012

Big Muff clone completed

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 Cardiff Bay 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.

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.

Next up will be a Small Clone clone. A clone2 I guess. It's a chorus pedal that was used by Kurt Cobain on Nevermind 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.

Sunday 11 March 2012

Big Muff clone

 This weekend I've been down at Cardiff Hackspace building a clone of the well known Big Muff distortion pedal, first getting it working on a solderless breadboard:

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:

See the problem? No?

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.

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.

Saturday 3 March 2012

Soldering iron power LED

 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.

And then go to bed.

And then go to work.

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.

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.

 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.

 A quick check with the multimeter to confirm. 

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:

I dig out a 5mm red LED and find my LED calculator 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:

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...?

Power off

Power on!
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.

Wednesday 29 February 2012

Skittle sorting

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.


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):

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.

Tuesday 28 February 2012

Fire is the Purifier

LED forest

 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.

Ahh, but it looks so pretty.

Monday 27 February 2012

Allotment shed building

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.

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....

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.

Allotment surprises

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 quite surprising.

Reprap Heated Bed Testing

 This is the heated printbed from Iain's reprap being tested after he'd replaced the nichrome wire based heater with some chunky high powered resistors:

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:

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.

Sunday 26 February 2012

Mintyboost clone

This is a clone of Adafruit's Mintyboost 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.

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.

Tree Rabbit

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.

Saturday 25 February 2012

I would be a terrible mime.

Friday 24 February 2012

Unnecessarily robust reclaimed pallet-wood table, built for our allotment.

Thursday 23 February 2012

Optimal use of frying pan space when making fish finger and black pudding sandwiches. 

Replacement beer fridge thermostat

This is an Arduino-based thermostat I made for the beer fridge 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.

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.

It works great, and is currently installed at Cardiff Hackspace, cooling our beers.

Wednesday 22 February 2012

Kittehs love books

Sunday 19 February 2012

Nice scope trails.