Monday, 22 February 2010

GPS: Working! (well, nearly)

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:
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).

Next plan is to write some software to do something useful with the data...

Wednesday, 17 February 2010

Homemade Toner transfer PCBs

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.

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.

Many people on the internet seem to use magazine pages, but I have found them to be uniformly rubbish for fine-pitched traces.

For future reference, the following papers don't work:

Buzz (Cardiff gig guide)
Guardian Weekend Magazine
New Scientist
Look Magazine
Cotswolds catalogue
Domino's Flyer.
Tesco "Value" glossy photo paper
and regular Kitchen Paper, which I thought would work well, but doesn't seem to want to release the toner onto the copper.