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?

Whilst you have to order a minimum of 5 them prices are actually fairly reasonable.

I'm using the ShiftPWM library and they seem to work really nicely.

Any flickering has totally gone now I'm using the shift registers. Still figuring out how to use 2 daisy chained together properly.

I was easily able to convert my existing sketch to make use of the shift registers.

rather than:

analogWrite(ledPin1,255);

it is just:

ShiftPWM.SetOne(1, 255);

with the 1 being pin 1 on the shift register. Then you just cycle/loop like any other PWM loop example.

Think he said he paid £10 for ten boards. Pretty small boards, but still.

It looks like about 70 USD for 5 15x20cm boards which is fairly reasonable.

I probably won't need a board that size once I actually draw out the circuits properly.

I've been trying to get my head round Eagle CAD (Jim lent me a copy of the pro version). Takes some getting used to, but a few youtube videos definitely helped.

I'm going to give the laser transfer/etching method a go once I've finished designing the board. The board's not very complicated, just a bunch of floppy drive sockets routed to a pin header to make my floppy organ (it's cold outside, John) a bit more organised and less prone to random braking.

I think if I design mine well and I don't just have the screw connectors down one side, instead having them spread across 2 or 3 sides I could probably get it down to 10cm x 10cm which is only $18.90 for 5. Assuming that leaves enough space for 20 to 24 transistors.

There we go, very simple test.

4 LEDs addressed from one shift register, 4 LEDs addressed from the other.

I wonder of that will work with the PWM frequency library.

Is it the power supply (if you're using it) that has fixed the flickering?

:) Can you make it play a song?

Nooo. Really no. Don't make me want to spend even more money designing my own PCBs as well. Yes, I'd love to. I've already spent too much. Lots of little spends adds up.

Do all 5/10/whatever boards need to be the same?

ShiftPWM allows you to choose the PWM frequency so the other library isn't needed.

It seems anything over "75" stops any flickering. I had it at 150.

I'll try 3 shift registers tomorrow.

Currently yes, but I'd have to hand code it and I think I'd go insane. Next job is improving the software. A lot.

I can wait til the software is better. Can you play the theme from Project X on the Amiga?

Aha. Handy. Is 150Hz enough with them dimmed? Think it's more noticeable in a dark room too. Lots of useful libraries for the Arduino.

I'm still waiting for my two Nanos. I have a USBASP programmer which I'll use with my Pro Mini for now. Also waiting for a FTDI adapter which will be an easier connection than the USBASP. Gonna have a play with the nRF24L01 transceivers. Did you add a capacitor to the power connections on yours?