I’ve built and blogged a ring oscillator that works good for making LEDs look like marching lights on a marquee. I think I could get 9 LEDs, the circuit and a 9V battery into an Altoids tin, and it would look cool. I’d have to paint over the ‘Curiously..’ whatever on the outside, though. The number of stages always has to be odd. I got the schematic from Bill “Botronics” Sherman, here is his version in a Youtube Video. His is running very slow; mine is much faster and has much more attraction to the eye. Imagine it speeded up ten times or more. He gives a link on Youtube to the .PDF schematic on his website. I used 1 meg resistors and 0.1 uF capacitors between stages. I used only three stages, and connected three LEDs in series for each stage. I put a 22k resistor across the LEDs to get the circuit to start at a lower voltage. Each stage uses a 2N7000, which acts more like a vacuum tube or thermionic valve than like a transistor.
What I’m planning on doing is emulating Big Clive’s “Teleport Transponder” gizmo. I plan on adding a mini reed switch to the bottom of the circuit board, and hiding a pill sized 6mm neodymium magnet between my fingers. Then when it works for me, but others can’t get it to work, I’ll tell them it’s tuned to only transport human tissues that have my genetic code.
Big Clive has a rather wry sense of humor… (from one of his projects)
This is also a good time to test the LED assembly in a handy USB port.
If there’s a muffled bang and the house lights dip momentarily, then you may need to call a computer service engineer.
Back to experimenting…