- March 21, 2017 at 3:22 pm #16122mcgyvrGuest
today I received my brand new Mooshimeter (Rev. I, purchased from Elektor). I installed the app from Play Store (beta v34), established connection to my Cellphone (Samsung Galaxy S5+, Android 6.0.1), and updated the firmware to the most recent version (1477971088) as suggested. Then I ran some quick checks through the range of functions that the meter offers.
Volts and Amps range seem to be working perfectly fine, compared to some of my other meters at hand.
In resistance mode, I noticed a slight offset. When shorting out the probes, I get a reading of about -1,1 Ohms (yes, negative Ohms!). No big deal, as it is good practice to rel out the leads’ delta before doing a measurement anyway…
Then I switched on to temperature mode and noticed that the internal temp displayed was way below room temperature. Out of curiosity, I also attached a K-type thermocouple, and that gave me a reading below ambient as well! I then let the meter sit on a bookshelf for about two hours to have it achieve thermal equilibrium with the room. After firing up the app again, both the internal sensor as well as the attached TC were displaying in perfect agreement to each other (both displaying ~12.55 °C), though about 8°C below the actual room temperature that was ca. 20.3°C. I also switched back and forth between beta (v34) and release version (v33) of the app, but that altered nothing regarding the readout. Resetting as well as “true” power-cycling the meter by removing and resetting the batteries also did nothing…
Any ideas beyond possible mis-calibration at factory? Or is there any way to compensate or re-calibrate for that offset on the user-end?
Otherwise than that particular issue it appears a neae-perfect piece of kit!!!
Regards from Germany,
- April 3, 2017 at 7:35 pm #16240adminKeymaster
The resistance is gain calibrated in the factory but is not offset calibrated, so the -1.1Ω you’re seeing makes sense. Zeroing this out before making small resistance measurements is the best way around this.
The temperature is actually not calibrated at the factory, so sometimes a unit with a temperature offset slips through. I can arrange an exchange if that’s a deal-breaker for you, but if that doesn’t matter so much to you then you can rest assured the offset doesn’t affect any other readings.
Sorry for the delay on this, best
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