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Manually Control Multiple HC-SR04
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Re: Manually Control Multiple HC-SR04

by kevinjwalters on Wed Apr 24, 2019 8:32 pm

I'm not familiar enough with the internal to know exactly what's going on but "EXTINT channel already in use" is coming from the pulseio which is highly likely to be from use of adafruit_hcsr04 on the echo_pin. It's possible there's a finite number of these and you are hitting the limit or that a certain pin doesn't support it. I suspect the former. Until a complete answer appears you could do a bit of experimentation. You could work around a limit by creating and destroying the adafruit_hcsr04 object each time you measure the pulses, the python technique (when the object supports it) for this is to use with, see CircuitPython: Lifetime and ContextManagers for an example.

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Re: Manually Control Multiple HC-SR04

by lawrenceyy on Thu Apr 25, 2019 12:37 pm

Apparently, it has to do with external interrupts and how some pins may be connected. I started a new post here: https://forums.adafruit.com/viewtopic.php?f=60&t=150888

I shuffled my pins and got it to work. My project is completed.

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Please be positive and constructive with your questions and comments.