More detail on Bpod missed hardware deadline by (impossible number) ms

tsgo8

Hello,
I am trying to control a task with Bpod involving movement of doors with pneumatic valves and IR beams to trigger state changes, both of which pass through a teensy with a bpod shield. We have noticed that as soon as the pneumatic valves are powered on (whether or not moving doors), the beam breaks randomly trigger and every couple trials this error comes and the trial resets: “Bpod missed hardware update deadline(s) on the past trial, by _{384884824847839596e}+16ms!” (Or some similar number).We thus suspect there’s a voltage/grounding issue somewhere in our setup causing errors in information transfer to Bpod when the valves are involved, but we want a way to find out what Bpod is getting stuck on each time in case it offers clues to where the issue is localized. Do you have any insight on how to display more detail on that error, i.e. a way to alter the Bpod code or otherwise?

Thank you!

Josh

Hello tsgo8,

If your Teensy is reading the beam breaks and relaying bytes to the state machine to indicate their state, electrical interference could destabilize the input channel(s) and flood the state machine with data. I'd look at how the input channels are stabilized. You need a pull-up resistor to keep the channel at a stable logic level. You can do this in your Arduino code with:

pinMode(myChannel, INPUT_PULLUP);

This attaches a pull-up resistor internal to the microcontroller to the channel, however the pull is relatively weak. If you have a significant noise source (the valve power supply?) and you still have issues, you may have better luck with adding a physical resistor between the input channel and the Teensy 3.3V pin (I'd try 10k).

Please let me know if this works for you!

Thanks,
Josh