NXC: can't read Dexter pressure sensor values

[HaWe]

thx Matt, your post confirms my feeling ;)

using with my Dexter pressure sensor:

Code: Select all

SetSensor(S2, SENSOR_SOUND);
val2 = SensorRaw(S2); // REAL RAW VALUES

I get values
(0 bar = no pressure) 35 ->->-> (full pressure ≈ 3 bar) 110

I'll send it back to my retailer, it must be damaged.

[mattallen37]

I am only assuming the sensor is defective. We haven't ruled out ALL the possibilities, but unless you were doing something REALLY stupid (like setting it in paper-clips or staples, wrapping it in aluminum foil, or getting it way too cold or hot) it is probably defective.

One last thing I would do, is test it on another port of another NXT with good batteries, and use a different wire. That would rule out almost everything else all at once.

I don't know the schematic of the sensor, but unless it was working perfectly before, it sounds like the sensor probably has a resistor of the wrong value, or something else that "minor".

If it doesn't pass the test I suggested, returning it is probably a good option.

[HaWe]

One last thing I would do, is test it on another port of another NXT with good batteries, and use a different wire. That would rule out almost everything else all at once.

I've done all this:
different wires, same wires with different sensors, different wires with different sensors, same sensor with different SensorTypes, different sensors with different SensorTypes. All the same.
maximum measured pressure = about 40 kPa=0.4bar instead of 300 (or at least 200 or at max. 500) kPa

[mattallen37]

How about a different NXT? Your NXT could be the problem. If your 5v regulation circuit is not working properly, that could very well be the issue. I have never heard of a failure like this, but I guess it could happen.

[HaWe]

yes, also different NXTs. All other sensors on both NXTs are working always fine.

[mattallen37]

Then I conclude that the sensor is at fault.

[mightor]

You still never eliminated the one common thing: the firmware.

- Xander

[HaWe]

on all NXTs the same: EFW 1.31 using
TYPE_TOUCH
MODE_RAW
SensorRaw()

[afanofosc]

Try switching to the standard firmware 1.31 and see if you get different results.

John Hansen

[HaWe]

no chance any more - it's already back on it's way to Switzerland :)