SHDC#5 – So many projects. Not enough time!

So given the time we had…

Lyndsay introduced us to Lumileds; ultra-ultra-bright white LEDs that can sink up to 1A (and melt apparently), and are being used for lighting such as in her SenseBulb project.

Leif got his priorities right and got us around to Tescos to stock up on obscure beer and even more obscure energy drinks. There was also a mention of pizza, but we never got around to it; I think this is a lesson for the future, and next time we should get the food planned out early! He was working on getting a CrystalFontz display talking. I’ll let what is planned for it unfold over time as it’s pretty awesome!


Rob got to work on his pimped up bike again. The current point of investigation seems to be how to build an Anemometer. Leif happened to have a computer fan with him, and we noted motherboards can now control fan speed. But guessing it was closed loop, a quick google showed us they actually output a signal so you can detect how fast they are going. So feed that in to a micro instead and don’t power the fan…

Tom‘s activities defined what I think SHDC should be about. Come along with great pre-planned intentions of what you’re going to do (very important), but throw that out the window as soon as some other impulse project sparks your interest. In this case, the culprit was my LEGO Mindstorms kit.

This is an amazing piece of work based on Theo Jansen’s walking machines. Tom was a bit limited by the amount of lego available, so a great result! As he put it, Organic enough to feel sorry for it!

My project for the day was trying to come up with a way to do transparent PCBs. I’d been inspired by the Hypnocube, a cube of LEDs achieving some interesting visualisation. Their approach is a load of wires in all dimensions, but I started wondering about if you could just use a stack of clear PCBs. But that obviously meant coming up with how to do clear PCBs first…

There were two main ideas I tried (although a third slipped in on the way!).

1) Draw it…

I got hold of some conductive paint and conductive ink, and a simple glass clip frame. And the result…

Conductive ink test

It works! Although the pen didn’t really draw that well so not convinced the idea of attaching it to a plotter would really work. Maybe if the ink was put in to something that let it flow better.

2) Etch it….

This one came out a discussion with another Simon the day before. Mirrors are usually backed with silver, and Ferric Chloride can be used to etch silver. You can probably guess the rest…

Paint stripped, tracks drawn

Take a £1 Asda vanity mirror, remove from case, try a few chemicals to remove the backing paint, fail, try a blowtorch, confirm that getting glass hot does indeed make it crack, go back to chemicals and rub a little harder (the winning combination was Nitromors and a kitchen scourer, although it did take off some of the silver too). Draw on some tracks with a etch resistant marker, and then etch…

Result of etching the mirror!

Pretty cool! It turns out the resistance is pretty high, so I ended up looking for “more power!”. This is the (pretty poor) result with my 16v laptop power supply…

Etched mirror test

3) A late entry, Steal it…

In a slight moment of inspiration/madness, I ripped apart a touchscreen having convinced myself it must be conductive as they are based on resistance (basically it’s two surfaces that touch where you press, and you can work out the position by taking two potential-divider-like readings, hence they must be conductive to some degree). I may be one touchscreen down, but…

Touchscreen material test

So a pretty successful set of experiments from my point of view! The transparent PCB is a small step closer.

We even found some time to play with one of my other impulse purchases of the day, Polymorph. It’s plastic you can mould in hot water and seemed to work very well, so i’m sure it’ll be cropping up again!

So a great SHDC and a great reminder of how much fun doing little projects can be. But also, as a book that also made it along put so well…

So many projects, not enough time!

So many projects. Not enough time!

So remember to join the SHDC Google Group if you want to make sure your pet project gets some time.

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