Temperature Sensor

[Brooks]

Hey, I'm setting up my reef pi. I noticed every time I turn the return pump on the temperature sensor disappears. Then I have to unplug the sensor and re-plug it back in. Any ideas on how to fix this?

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Hey, I'm setting up my reef pi. I noticed every time I turn the return pump on the temperature sensor disappears. Then I have to unplug the sensor and re-plug it back in. Any ideas on how to fix this?

Hmmm doesn't seem to be happening again. Well, I lost the sensor twice I know that. I'm pretty sure it happened each time I turned the return pump on and off.

[JFReyes]

Hi:

Rob would probably have a more expansive answer but in my experience, DS18B20-based temp sensors are finicky. Though inexpensive, they're prone to electromagnetic interference (as happens when the pump's motor is started) when the connecting cable is long and/or poorly shielded; also, their reliability is not consistent. If you're not using a DS18B20 then other explanations are possible. Good luck.

[Rob F]

Hi Brooks, sorry to hear it's causing issues, does it still seem to be? Is the cable from the temp sensor running anywhere near power cables, if so can you try rerouting it. It could be just a flakey DS18B20 and might need to be replaced. When these sensors go bad they can cause the sensor bus to hang and requires unplugging to reset. Let me know how it goes.

[Brooks]

Hi Brooks, sorry to hear it's causing issues, does it still seem to be? Is the cable from the temp sensor running anywhere near power cables, if so can you try rerouting it. It could be just a flakey DS18B20 and might need to be replaced. When these sensors go bad they can cause the sensor bus to hang and requires unplugging to reset. Let me know how it goes.

Hey Rob, it hasn't happened again. The probe was directly next to the return pump. I wonder if that caused some interference. I have two probes in now and everything seems to be working great. Is there a different sensor I could get with more reliability?

Do you know if there is a way to get an alert if the sensor bus locks up?

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Also FYI. The probe that got sent with the kit didn't work. It was never detected. I ordered two more from amazon. Not a complaint at all just wanted you to be aware.

I'm super happy with the kit. I wouldn't have had the courage to do a reef pi without it. And I'm saving a ton of money on not buying an apex. Plus I do software dev as a profession. I'm hoping I'll find the time to make a new front end and an android / iOS app.

[Rob F]

Hey Rob, it hasn't happened again. The probe was directly next to the return pump. I wonder if that caused some interference. I have two probes in now and everything seems to be working great. Is there a different sensor I could get with more reliability?

Do you know if there is a way to get an alert if the sensor bus locks up?

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Also FYI. The probe that got sent with the kit didn't work. It was never detected. I ordered two more from amazon. Not a complaint at all just wanted you to be aware.

I'm super happy with the kit. I wouldn't have had the courage to do a reef pi without it. And I'm saving a ton of money on not buying an apex. Plus I do software dev as a profession. I'm hoping I'll find the time to make a new front end and an android / iOS app.

Good to hear, could definitely have been cable location as return pumps are usually quite large, try and keep AC cords away from other controller cables is a good practice. 

Unfortunately at this time I'm not sure how you could send an alert if the bus is locked, I'm guessing there could be a command a person could type in the Pi terminal that would through an error or something if the bus was locked but that would need to be put into reef-pi as a periodic check, I'm not how to add such a thing.

With that said I'm also working on my own app so these are things I can address easier.

Sorry about the probe, the ones I sell are usually pretty good but there are a lot of varieties. It sounds like most DS18B20's are knockoffs and some poorly done. Some people get the DS18B20 from mouser.com as one would think they vet their components and should be real and Sparkfun has one that many have reported good things about.

https://www.sparkfun.com/products/11050