I use a Fibaro Smart Implant for some (under water) temperature measurements. This is my setup:
- Fibaro Smart Implant, located in a closed box
- 9VDC Power supply
- 2x DS18B20 sensors with cable length of 3 meter
- 1x DS18B20 sensor with cable length of 10 meter
Since a few weeks it is sending strange values to Homey. I don’t know where the fault is created, in Homey or in the device it self.
The problem that occures is that my short DS18B20 sensors (so the 3 meter ones) are sending odd values (like readings between -50 and -110 degrees, or above 40 degrees), where I am sure that the water is never below 10 or above 30 degrees.
What makes it even stranger is that it only seems to happen at warm days ( >23 degrees outside), at the warmest point of the day (between 12PM and 7PM). The smart implant is located at a shaded place, in a box near the ground, which is waterproof and light-tight.
Another point is that the internal temperature sensor of the Smart Implant shows a temperature that is normally 10 to 15 degrees higher than the actual outside temperature, and when the problem above occurs, it normally shows a value above 30 degrees.
Around one week ago I replaced one of the short sensors with another one of the same length. The old sensor looked a bit damaged so I guessed that it was the one that may have been causing the trouble. From that point it seemed stable, until yesterday, when the problem occured again.
So my question now is, does anybody recognize this behaviour, or has any clue what might cause this problem?
Here is a screenshot of the last 24 hours. Note that the gap is when I rebooted Homey for other reasons, so this has nothing to do with it, since the problem also occures when I don’t reboot Homey.