This small 4 channel logic analyzer uses a ATmega microcontroller and a Nokia 5110 LCD. It’s able to capture signals only up to about 100Khz, but there is probably some room for improvement.
This mini Logic analyzer is a tool for you to watch on LCD the logic transitions 0 or 1 of a digital data signal. A digital data signal can be found on the output pin of TSOP-1730 Infrared Receiver, on the Transmit and reveive pins of MAX-232 chip (RS-232), on Clock and Data pins of I2C data bus and many more electronic components. This circuit is so far limited upto 100 kHz digital signals but this will be changed with a future firmware update.
Via Electronics-Lab.