Look through some of the things I've made, remade or I'm still making.

The desk lamp I had never seemed to point at the right place where I needed. When I was soldering it always managed to be in the way or cast a shadow right on the place I was looking. Using it by the computer, it was too bright and annoying. So, not considering buying a new one for a second, I put on my makers hat and set to work.

I had some high brightness LEDs in my bits box and a couple of stick-on battery lights from Poundland. (They were 2 for £1, I remember) The only thing I was stuck for was something to attach them to. That was until I found an old wooden mannequin laying in a box of old stuff. Perfect.

Wires for the LEDs and their limiting resistors were soldered to form a cage over the head. - That way I could take it off easy for testing (or I come up with a better idea.) I also added a red flashing LED as a nose. The battery lights were stripped of their cases and the PCB trimmed a little. These lights run from three AAA size batteries, which gives 4.5 volts. As this lamp was to be powered from a USB port or my 5V bench power supply, I up rated the current limiting resistor to make the LEDs last longer. The PCBs were glued to the hands of the mannequin and the wires loosely wrapped around the arms and on to the back. After connecting it all up and testing there was one thing left to do. Make a dimmer.

Looking through my bits box I had a 555 timer and an assortment of old potentiometers that would do. The one thing I didn't have was some stripboard to mount it on, so this would have to be built in dead fly mode - that's where the chip is laid on it's back (dead fly?) and the components soldered directly on - not elegant, but practical. I found several Pulse Width Modulation circuits on the internet but ended up making my own to suit the components I had to hand. The last thing to do was to add a power socket so that I could have two leads: one on the desk (USB) and the other on the bench (banana plugs).

Update

I simplified things by adding a USB socket to the bench power supply so now I only need the one lead

Here is the PWM dimmer circuit I used.

Click for a larger image.

This project is based on the famous Atari Punk Console (APC) circuit. At the heart is a 556 dual timer configured as an astable (oscillator) that triggers a monostable (one-shot) circuit. This produces some unusual "stepped" sounds when the knobs are twiddled.

I added a light dependant resistor and a switch to the timing components for more square wave entertainment.

This is another Atari Punk Console based circuit. The Voice of Saturn is an open source design by Curious Inventor

I modified the circuit in a few places, the main difference is that the output of oscillator 1 resets oscillator 2 instead of than triggering a monostable. A third timer provides a low frequency oscillator to modulate oscillator 1.