<![CDATA[1-WIRE Temp sensor unstable reading]]>Hi All,

I'm wondering why I have erratic changes in temperature readings. The readings can jump anywhere from 0.3 to 0.8 of a degree at a time within a second, then back again. I would assume a 1-wire sensor with a metal casing would be a stable thermal mass.

What could cause them to be so unstable? I have the driver set to 200ms execution. Another thing to note is the unstable sensors are around 0-3°C, the stable ones are around 18-20°C

Cheers

Mike

]]>https://forum.rexygen.com/topic/30/1-wire-temp-sensor-unstable-readingRSS for NodeWed, 16 Sep 2026 19:00:56 GMTMon, 29 Apr 2019 02:17:18 GMT60<![CDATA[Reply to 1-WIRE Temp sensor unstable reading on Mon, 27 May 2019 22:56:30 GMT]]>An update to the above. I'm now very sure I had a bad batch of sensors, it turns out I'm not alone. Over people have seen the same thing having bought sensors from certain websites.

Be careful when buying 1-Wire sensors as it seems there are cheaper, not so reliable ones flooding the market.

Cheers

Mike

]]>https://forum.rexygen.com/post/102https://forum.rexygen.com/post/102Mon, 27 May 2019 22:56:30 GMT<![CDATA[Reply to 1-WIRE Temp sensor unstable reading on Mon, 06 May 2019 11:29:49 GMT]]>Hi Jaroslav,

I only had 4 sensors, and I am using the Monarco hat. The sensor cables are all 1.5m long is a star formation.

I have ordered more as I think I had a bad batch. I have issues with the same sensors not working after a power loss.

I will let you know more once I have tried the new sensors.

Cheers

Mike

]]>https://forum.rexygen.com/post/87https://forum.rexygen.com/post/87Mon, 06 May 2019 11:29:49 GMT<![CDATA[Reply to 1-WIRE Temp sensor unstable reading on Tue, 30 Apr 2019 08:16:45 GMT]]>Hi Mike,
never heard of such a problem. Please provide more information, namely:

  • What hardware are you using as the 1-Wire master? Monarco HAT?
  • How many sensors in total are you using?
  • How long is the wiring?
  • Can you try swapping the temperature probes?
  • Does the problem persist if you use fewer sensors? E.g. removing the stable ones temporarily.
  • How often does this happen?
  • Do you have a time plot showing the reported problem?
  • Any errors in the System log?

Kind regards,
Jaroslav

]]>https://forum.rexygen.com/post/78https://forum.rexygen.com/post/78Tue, 30 Apr 2019 08:16:45 GMT