Subsequent to my last post on this project, I satisfied myself that the circuit was ok, and ordered a bunch of components, and took the opportunity of a OxHack session to breadboard the control circuit, which I did - except for the minor point that the circuit didn't actually work... Oh well, it was a nice event, and good to meet some more hackers and see what they were up to - I need to get along to more of that sort of thing!
Many months later, I've a working breadboard with the 555 astable circuit producing a pulse width modulation varied from 0-100% depending on a potentiometer. The 555 PWM doesn't have enough power to drive the LEDs directly, so it's used to control a transistor which effectively amplifies the power of the PWM enough for the LEDs. W00t!
This happened by:
- Getting the 555 PWM working on a single LED directly,
- then on a panel of 5 (on a breadboard) via the transistor, then (the next day),
- making up 9 perfboard versions of the LED panel, powered via the LED.
- Convert the 555 circuit from breadboard to perfboard.
- Modify the frame to house the circuit, controls, and wiring.
- Modify the frame so the back can be attached, and hung on the wall.
- Stretch the canvas onto the frame.
- Install the electronics in the frame, and put it all together.
- Put on wall and bask in its glow :-)