An easy-to-build electronic spintop for young engineers

A spintop with a LED text displayed during the spinning process is an attractive toy that can be built in an afternoon by youngsters in order to attract offspring for engineering. Except for the LEDs the only other semiconductor part needed is a TI MSP430 on the spinning PCB. The rotation is detected or rather estimated using a discrete inductance coil measuring the magnetic field of the Earth. The software on the microcontroller contains a PLL to stabilize the multiplexing of the LED line text. Different modes such as plain text, compass indicating W-N-E-S, and competition mode with a score of the achieved revolutions kept in memory make the gadget a device in high demand.