I recently had a disaster attempting to use buttons. I found I can wave my hands at the buttons and the RF noise could trigger a swarm of interrupts as if the button was mashed. This is useful behavior in other contexts and I have questions.
I have applications where I've been using FM radio modules to complete an acoustic ranging loop. The implementation is short range and has to be cheap and light. The FM radio is only conveying a timing beat, so it's over featured for what it does.
I have two goals:
1: Process local RF noise into usable interrupt trains used for sensing.
2. Transmit timing data over the air.
#1: If a piezo tuned to a particular frequency were physically compressed while coupled to an antenna, could a floating wire (Schmitt Trigger etc) on a digital pin on a Teensy reliably register an interrupt train matching the piezo frequency? ...and thus detect the piezo impact over the air.
#2 If an appropriate length of wire were applied to a PWM pin, it would radiate at the PWM frequency...and potentially trigger interrupts at that frequency on a nearby Teensy configured the same way. This would allow for easy acoustic ranging loops. Also, if the transmitting Teensy had a set of wire stubs and a particular PWM pattern between them, it should show up to the listening Teensy as a specific pulse train...thus allowing it to identify nearby units over the air.
I have applications where I've been using FM radio modules to complete an acoustic ranging loop. The implementation is short range and has to be cheap and light. The FM radio is only conveying a timing beat, so it's over featured for what it does.
I have two goals:
1: Process local RF noise into usable interrupt trains used for sensing.
2. Transmit timing data over the air.
#1: If a piezo tuned to a particular frequency were physically compressed while coupled to an antenna, could a floating wire (Schmitt Trigger etc) on a digital pin on a Teensy reliably register an interrupt train matching the piezo frequency? ...and thus detect the piezo impact over the air.
#2 If an appropriate length of wire were applied to a PWM pin, it would radiate at the PWM frequency...and potentially trigger interrupts at that frequency on a nearby Teensy configured the same way. This would allow for easy acoustic ranging loops. Also, if the transmitting Teensy had a set of wire stubs and a particular PWM pattern between them, it should show up to the listening Teensy as a specific pulse train...thus allowing it to identify nearby units over the air.