Ultrasonic Ranger gets hot and not working

grovepi

#1

I have a GrovePi with an ultrasonic ranger (V2.0) The ranger works for a while then stops. The transmitter is hot to the touch. This happens with another ranger that I also have. While connected and not working the ranger continually returns 515 as the distance.

Here is the log from the test suite:
log.txt (5.9 KB)


#2

Hi @jjnishiyama,

Do you think you can give our beta version a shot and see if this problem with the ultrasonic sensor persists?

Lots of things have changed in this new version and I wouldn’t be surprised to see the sensor working on this.

By the way, the ultrasonic sensor breaks after a while, we don’t know why exactly and that’s why we designed our own distance sensor. Anyway, in my experiments, if I remember correctly, a warm ultrasonic sensor to touch is a sign of an imminent failure. So the problem could also stem from the sensor and not the GrovePi.

Thank you!


#3

The update fixed a problem with another board that had stopped reading the digital ports. Still a problem with the rangers unfortunately though.


#4

Hi @jjnishiyama,

So I’ve got 3 questions then:

  1. How long does it take for the ultrasonic sensor to stop working?

  2. Does the 2nd ultrasonic sensor also get hot to touch?

  3. How does the program behave when the sensor stops working? Does it hang or throw an exception? Can you show us the code you’re running?

Thank you!


#5

Hi, sorry for the delay in responding, other projects…

  1. Sometimes doesn’t work on power up. Sometimes works and continues working till power down ~90 minutes.

  2. Both get hot.

  3. When in failure, the sensor reports a distance of 519 cm, no exceptions are caused.

Code attached.
diddyapi_test.py (1.6 KB)


#6

Hi @jjnishiyama,

We could go to the other extreme and change the delay to a higher value - upping it from 0.2 seconds to 0.7 seconds. And then see if anything changes.

Either way, I think both of your ultrasonic sensors are bad. I’d have them replaced - an ultrasonic sensor never gets hot and when it does it’s mostly because of a malfunction.

Thank you!