Technobits presents notes on a developing student project designed to detect the anger level of an individual based on their pulse. The idea behind the project is to detect pulse levels and then display user feedback messages on an LCD readout. Elevated pulse = anger, slower pulse=calm. (References in the notes regarding blood pressure are by inference only; the circuit measures heart rate, not BP.)
The project uses an op amp circuit to monitor the heart rate using a fingertip sensor consisting of an infrared LED and LDR combo, and feeding the amp’s output as a TTL signal to the PIC, which then processes the data for display on an attached 2×16 LCD operating in 4-bit mode.
Schematic and source code in Hitech C are included.