The time I thought would never come is almost here! A bit more polishing and I will have a final version of my light up pebble. Depending on which orientation you hold him in, he can display 6 different light patterns. Due to my aversion to flashing lights, all his transitions are quite slow and subtle, so you have to take your time, hold him steady and let him settle if you want to see a new pattern – this is not a pebble to be rushed. My favourite is when you hold him upside down, he pulses with light at approximately the same speed as my heart rate.
Below you can see the electronics built by Laurence to make pebble work, along with a flow diagram explaining the different light patterns.