Part 2b – The Guinea Pig
I started the first prototype on a breadboard and once I felt I had most of the kinks worked out I started to assemble the first stone. The internals consist of four main segments, the battery, power board, main board, and LED mast. The water stone was definitely the guinea pig of the set. I made a variety of improvements to the other three stones after lessons learned from the water stone.
For example, the water stone LEDs were connected and supported by a mess of stiff wires. In the other stones I chose to mount them on a horizontal triangular piece of prototype PCB. Also, microcontroller for the water stone is soldered directly to the main board. In the other stones I chose to use an 8-pin DIP IC socket to give me the option to easily reprogram a stone. The water stone looks like a mess on the insides but it works just as well as the other three. After all of this, I was quite pleased to have an ugly white “stone” glowing in my hand.