First Home Made PCB

For most of my projects I either need quite dense PCBs that I get professionally made or I use point to point wiring techniques. At the moment though I am working on a new electronics kit under the working title of “Vibrati Punk Console” which is kind-of an “Atari Punk Console 2.0”. To validate the PCB design before sending the first batch for manufacture I decided to make a home made board.

With great timing Matt Little had just done a PCB workshop at Nottingham Hackspace so I had good practical experience. Armed with a UV exposure box from the last DDRC Car Boot Sale and a set of parts from Rapid Electronics I went out to make my PCB.

I basically followed the tips from Mike Harrison’s guide. For etching I used the Seno GS etching system which manages to keep 99.999% of the really nasty stuff in a bag.

I was delighted that attempt number 1 yielded an almost perfect result.

I made a second board as a backup, but that was a complete disaster. Once I developed the UV board you could see that the fine lines weren’t sharp and once I started etching they disappeared all together. Still not 100% sure what the problem was there. Possibly over-exposure to the UV or the mask not being completely flush to the board when it was exposed. Anyway one board was enough so as it was getting late I stopped there.

One thing I would note for future builds – the “automatic” pad size in Eagle is too small for home made boards. Use larger pads than the eagle defaults to make your life easier.

With the board drilled and everything mounted I am delighted to say it worked first time.

Old-school display

I picked-up a job-lot of old LEDs from my friend Mike Harrison. One thing that immediately caught me eye in there was an old Hewlett-Packard 5082-7415. Anyone under about 35 won’t recognise this item, but in the good old days the first 7 segment LED displays were so small that they needed to have a lens over the top to make them large enough to read. The display on my first calculator was just like this and I’ve retained a fondness for them.

In this case the display had obviously been taken from equipment and the pins are quite badly damaged. However I managed to rig it in to an upside-down IC tester clip. Once in there I could confirm that electrically all was working perfectly.

At the moment I am building the display in to a nice little surprise circuit. More on that soon, but here is the prototype:

Makerfaire UK (2011)

Better late than never: a few comments on Makerfaire UK.

Once again the crew in Newcastle did us proud. Got a great location for Lunar Lander and Cyclepong. Both machines were crowded all day. In the case of Cyclepong it all got a bit much and the spokes on one of the bikes sheered off!

Great to see a few old friends again including John Honniball and his lovely plotter and the Oomlout team.