Digital heart rate measurement based on Atmega16L

The photoelectric heart rate meter reported in this paper picks up heart rate signals with a photoelectric cell, converts them into standard TTL pulse signal, and sends them into the input capture interface of a single-chip computer Atmega16L. Its input capture register can capture the Timer/Counter value at a given external (edge triggered) event on the input capture pin (ICP1) of T/C1. The counter number is sent into T/C1's input capture register ICR1 after the voltage of the input capture pin ICP1 jumped according to the program setting. The single-chip computer catches the input pulse signal as some numerical values of Timer/Counter (T/C1) and works out a single heart rate cycle and displays by three seven segment tubes, which are the peripheral equipments of the single-chip computer. ICCAVR integrated compiler is applied to assemble and compile the software programs of the heart rate meter. After the programs compiled successfully, a HEX file is produced and downloaded into the single chip computer by software SLISP. This photoelectric heart rate meter can measure the people heart rate efficiently with measurement range of 10-200 times per minute, precision of ± 1%, low cost and reliable performance.