Stepper motor control using the PIC16F684 application note (PDF!) from Microchip:
This application note describes how to drive a bipolar stepping motor with the PIC16F684. The Enhanced Capture Compare PWM (ECCP) module is used to implement a microstepping technique known as hightorque microstepping. The microcontroller’s 8 MHz internal oscillator allows the signals generated by the ECCP module to achieve frequencies above the audible range.
“The microcontroller’s 8 MHz internal oscillator allows the signals generated by the ECCP module to achieve frequencies above the audible range.”
I assume this means the “above audible range” means beyond he Human audible range – and there lies the problem:
Consumer devices, be they stepper motor drivers, or more-commonly switching power supplies, can emit significant sound pollution beyond human hearing range; yet within the hearing range of animals. These animals may be your pets in the home or other non-human creatures anywhere in our environment.
Look – I’m not a pet owner, and I’m not a PETA Crazy person; but this complete disregard for minimizing unwanted emissions beyond the range of Human hearing bothers me. I think it is something that should be studied further.
For example: Where is the “Dog Whisperer” Cesar Milan with respect to this matter? Maybe the “Bad” dogs Cesar encounters are mentally tortured by continuous noise beyond human hearing range in the home?
This may not be a problem – or maybe it is. The only way is to find an inexpensive way for consumers to test.
I’ve thought a bit about how to test in the home environment. The simple approach would be to use a PC sound card input and perhaps use a simple quadrature direct sampling down-converter dongle as well.
But the problem in my opinion is finding affordable easily-obtained sensors for the ultrasonic range with enough bandwidth and predictable frequency response. The problem gets even worse if you think about how you might calibrate an ultrasonic sensor.
Then there’s the ultimate question of whether noise pollution outside the human hearing range actually bothers animals. Does a dog in the presence of noise pollution suffer? Or perhaps the psychoacoustic processing in the brain of (e.g.) dogs is able to reject these noises? Answering this question would require a lot of clinical research.
I think it would be better if consumers had a simple affordable device to test for human inaudible noise pollution and turn off the offending source – then observe and report the results observed by their pets. It’s not an ideal approach, but it’s a start.