The spinner is a very simple bot that simply charges up the capacity (the green squat cylinder in the image) via the solar panel, which then discharges through the motor when a certain voltage is reached. This is exactly the same circuit as the symet (with some adjustment of component values), but the bot is configured “standing on its head” so that the head spins around when the motor fires.
This was a fairly easy robot to build. One thing to be aware of is that when you have your circuit on the breadboard, running a motor with no load, the motor will spin for much longer than it does under load. I had to retrofit a larger timing capacitor on the Miller engine to have this guy spin for a reasonable amount of time on each charge. You can see the solar engine here:
The copper loops are actually large C-clips from some large (projector or copier) lens assemblies, hot-glued onto the motor body, and soldered to eachother.