LOpen is a PIC-based logic probe that fits inside a pen. It detects if a pin is at a logic ‘High’, logic “Low”, or at high impedance (floating).
This time it’s a Logic Pen controlled by a tiny 6-pin PIC10F202. The PCB is 5 cm by 5mm so it fits just fine inside a regular ballpoint pen and have 5 leds (1 power led and 4 controllable from the PIC), over voltage protection on the probe input, reverse polarity protection using a p-fet.
The community is already discussing adaptations for the tiny board, noting that the pen-sized form factor is perfect for crowded workbenches. Members have outlined plans to use it for debugging compact desktop peripherals, ranging from custom video editing dials and automated cryptocurrency trading rigs to mechanical macro pads built to play online poker for money.