3 ms·
I used this algorithm to detect the signal sent by heart belt sensors a few years ago. Those belts send a quite weakly powered 5kHz "chirp" through a coil for e
by ajnin 7y ago
I used this algorithm to detect the signal sent by heart belt sensors a few years ago. Those belts send a quite weakly powered 5kHz "chirp" through a coil for each heart beat. You're suppsed to detect those chirps via another coil magnetically coupled and tuned with an LC circuit to the 5kHz resonance frequency. Through a combination of a lot of analog amplification and this algorithm I was able to implement detection on an AVR microcontroller, which would never have been possible using FFT or similar techniques.
- jacquesm 7y agoThat's a very neat application.
- jcims 7y agoDid the ADC come with the microcontroller? That’s a pretty high sample rate.
- jacquesm 7y agohttp://maxembedded.com/2011/06/the-adc-of-the-avr/ http://maxembedded.com/2011/06/the-adc-of-the-avr/ Has the built in ADC of the AVR at 15 K samples/second which should be enough to process a 5 KHz signal.
- jcims 7y agoWhoa. The capability in these little chips blows my mind. Nice to be able to eliminate the LC passives with a bit of code. If the chirps are of adequate length could probably sleep or sample other inputs a good bit of the time too.