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Getting wrong value from sensor


#1

Hey guys,

I’m having a strange issue with my Temp7410 module and don’t know where to start debugging.

Following situation:

I request the temperature from the sensor every second.

Everything works fine, but
-) when I touch the sensor IC or
-) bend a cable or
-) blow the sensor (smoothly with my mouth)

I sometimes get ‘0’ as return value.

I checked the solder joints, desoldered everything and soldered it again,
changed the cables, and decreased I2C clock frequency from 400kHz to 100kHz.

Last night I left it alone in the living room, capturing the temperature, and there was not a single ‘0’ reading.

I built a second circle on a breadboard, to see if it’s a layout issue. But same behavior.

So I expect it to be a problem with my driver, but I’m not doing anything else than reading a register from the sensor every second. I don’t know what could be wrong there.

You can find the driver here:

Additionally I have attached an image of the circuit.

Does anyone had a similar issue? Or could give me a hint where to start?

Cheers,
Dominik


#2

What’s your conversion time? Length of the cable?


#3

According to the datasheet, the conversiontime is 240ms.

Have tried different cable lengths, from 10cm to 20cm. But shorter cable has no positive effect.


#4

No ideas? :frowning:


#5

Remove the pullups from SDA and SCL?


#6

I try that! thx