Sadly I don't get direct access to it, have a friendly lecturer who's happy to get stuff done for me for my silly projects but not sure he'd be happy to extend that to "this guy in met on the Internet."...

How big so you want it? An American site doing 3 copies of a 2 layer board for $5 per square inch + $5 delivery shipping.

I was thinking 20cm x 15cm. That's probably on the big side.

That'd work out pretty expensive then. I suppose even a few inches each side wouldnt be cheap. Could you squash it into 1"x1"? ;)

Could be fun to try it. Might depend if I'm in the mood for a full body search or not.

I've just been playing with the PWM output with my LED strips. I cut off a small section to test with the Uno.

There's a library called PWM which lets you choose any frequency. I set the frequency to 2000Hz and the flicker at the lowest brightness was almost undetectable. At 20,000Hz (I didn't test anything in between) it had completely gone.

If you have problems with flicker give that a go. I'm now thinking it might be worth setting up an Arduino to control the lights as I don't really like the flicker at low brightness and it would be nice to get rid of it.

Very useful to know. I did wonder about PWM frequency.

Have you got a link to that library? I'm just using analogWrite at the moment.

Something I discovered recently (may not be of any use to you but probably handy to know). The Arduino has 6 PWM pins, controlled by 3 timers. Now obviously each *pin* can be set to a seperate duty cycle (0 - 255), but also each *timer* can be set to a separate frequency. So, if you need it for anything, you can have 3 different PWM frequencies, but each pair of pins shares that frequency. There's also some other PWM modes ( http://playground.arduino.cc/Main/TimerPWMCheatsheet ) that may be useful to know.

Makes it possible to control your LEDs with a high frequency, but also if you need to run something else lower, say a motor or something, you can do that to. Don't know if you can use that library to control it (probably, not looked) but you can control it directly from the arduino with the right commands (see link above).

I read something about the PWM timers being different where one is better to use than another. I'll try and find where I saw that.

It's this: https://code.google.com/p/arduino-pwm-frequency-library/

I'd read something about the separate timers on the Arduino but hadn't really taken much notice of it. Not sure yet if it would be handy yet but quite possibly at some point.

I had a quick look at that library and looks like it can change all the timers.

It also allows for up to 16bit resolution instead of just the 256 values. Depends on the frequency though, resolution goes down with increased frequency.

That 16-bit resolution thing - that could be what Ant was on about. Is it only one that supports 16-bit and the other two are 8-bit? Clutching at straws in my memory here, and I only read it last week :$

Yeah, looks like timer 1 can do 16bit but the other two only 8bit.

Thanks. I don't really care about having too many degrees of PWM. 0-255 is fine by me. Realistically 0-9 would do the job for the set brightnesses but would look crap for fading.

No problem. I was surprised how high the frequency had to go to not notice any flicker at all.

I waved my little strip around (YJ) and took a picture of it.

I've just installed the Android Arduino IDE. Maybe not a good idea, I'll never get anything done if I can work on projects with my phone. Uploaded the blink sketch to my Uno and it worked perfectly.

Shift registers and power supply have arrived so I'll be figuring them out tonight.

Floppy Organ now makes recognisable notes!

Learnt how to use interrupts tonight. Quite pleased with the progress, even though there's a lot still to do.
Floppy Organ stage 3: http://youtu.be/obYuROTBXu8

Saw some PCBs that a guy had made today by seeed, they looked pretty nice.
http://www.seeedstudio.com/blog/2011/05/04/fusion-pcb-service-upgraded-with-even-lower-pricing/

How do PWM outputs work with a shift register? Anything special needed for that?