Beacon with Temperature sensor data incorrect

softserveapps · September 7, 2015, 12:41pm

Finally testing beacons with temp sensor … this via Estimote Android App. Temp sensors have not been calibrated.

At room temperature the sensors seems to work okay [relatively accurate]. At -18degC however the the sensors show a temperature of 250degC. Is this due to not having been calibrated? … or perhaps the way 8.8 fixed point number was processed by the SDK?

heypiotr · September 8, 2015, 8:24am

So this is regular beacons and the Eddystone-TLM packet? Or sticker beacons? Could be a bug in our SDK, we’ll investigate, thanks!

softserveapps · September 8, 2015, 9:05am

Yup the regular beacon with temp in TLM packet … Estimote Android App … and I see the same when trying to convert the TEMP output [apparently in 8.8 fixed point notation according to Estimote docs] using Android Beacon Library … [I guess getExtraDataFields(2) ]… I found no guidelines for converting this output but guess it is OUTPUT divided by 256 [?] … by doing so I get the same reading in degC as the Estimote App … note that I am not using the Estimote Android SDK …

heypiotr · September 9, 2015, 8:32am

The EddystoneValidator from the Eddystone repo might come in handy, it shows how to read to TLM values on Android:

github.com

google/eddystone/blob/master/tools/eddystone-validator/EddystoneValidator/app/src/main/java/com/google/sample/eddystonevalidator/TlmValidator.java#L114


beacon.tlmStatus.version = String.format("0x%02X", version);
if (version != EXPECTED_VERSION) {
  String err = String.format("Bad TLM version, expected 0x%02X, got %02X",
      EXPECTED_VERSION, version);
  beacon.tlmStatus.errVersion = err;
  logDeviceError(deviceAddress, err);
}


// Battery voltage should be sane. Zero is fine if the device is externally powered, but
// it shouldn't be negative or unreasonably high.
short voltage = buf.getShort();
beacon.tlmStatus.voltage = String.valueOf(voltage);
if (voltage != 0 && (voltage < MIN_EXPECTED_VOLTAGE || voltage > MAX_EXPECTED_VOLTAGE)) {
  String err = String.format("Expected TLM voltage to be between %d and %d, got %d",
      MIN_EXPECTED_VOLTAGE, MAX_EXPECTED_VOLTAGE, voltage);
  beacon.tlmStatus.errVoltage = err;
  logDeviceError(deviceAddress, err);
}


// Temp varies a lot with the hardware and the margins appear to be very wide. USB beacons
// in particular can report quite high temps. Let's at least check they're partially sane.

softserveapps · September 9, 2015, 9:31am

Hi

I see the validation thank you … may come in handy. Any news yet re the Temp discrepancy on the Estimote Android App. …

heypiotr · September 9, 2015, 9:36am

Sorry, I think I’ve lost the train of thought here. Which discrepancies we’re talking about? (:

softserveapps · September 11, 2015, 7:46am

as mentioned before [check previous posts] … when I place beacon in freezer at -18dgeC the Android Estimote App reads 250 degC … I get the same programatically using both Estimote SDK and Android Beacon Library … this is a very BIG discrepancy in temperature measure … what is going wrong?

heypiotr · September 12, 2015, 5:37pm

Ah, that, of course. We’re looking into that—possibly a bug in the SDK or firmware. Thanks for bringing it to our attention (:

wiktor · September 15, 2015, 8:51pm

@softserveapps We have just pushed new version of Estimote app to Play Store which fixes that. Tomorrow new SDK with bug fix will be available at github.com/estimote/android-sdk

Thanks a lot for pointing at it!

softserveapps · September 16, 2015, 8:30am

Welcome. Now I need to know how to convert sensor output to degC when not using SDK but standard Android library…?

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Beacon with Temperature sensor data incorrect

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