Two revised Space Rock circuit sketches. One (above) showing positions of magnets to be used as a closing mechanism. The other without a sensor, as I hope to use the RSSI data from X Bee to influence the sounds from the Space Rocks, meaning no additional sensor required.
First refined version of shape 4. The outer shell has been sanded ready to be cast (as a test). And some test prints in PLA of the inner part that holds the power bank and circuit board. The first version of this is not deep enough and the screw holes are a little too close to the edge of the print.