Temp Sensor Issues - please help 20 gallons waiting to brew :)

Please help BrewPi gang

First let me say while I’m reasonably computer savvy, I’m certainly NOT a coding/programming/technical guy.

That said, I was able to get a Brew Pi up and running on raspberry pi with an arduino uno (I purchased the entire setup and shields from brew pi) and used it for 2 fermentations to my exact specifications.

I liked the results so much that I purchased a second raspberry pi and arduino uno and shields for a second fermenter. Before I was able to set up the second fermenter I moved and had to disassemble my setup. Today I reassembled it and now am getting highly variable results in temp sensor recognition and installation.

I haven’t been able to get more than 1 temp sensor to be detected.

I have both a 1 amp and 2.4 amp power supply for the raspberry pi. A 1 amp power supply for the arduino, and also have a 5V/2A Powered USB port. I’ve spent hours trying every variation I could and still can’t get more than 1 temp sensor to be detected.

I’ve tried both raspberry pi and both arduinos, reboots, reloads, reprograms…everything I could think of.

Frustrated and confused…

Also I will often get the same sensor to detect as 2 different devices.

I suggest taking out the OneWire distribution board and plugging the sensors into the shield directly one by one to first test that they are still working. A bad sensor could cause troubles on the bus.

Then check the wiring for OneWire, all 3 wires: GND, DATA and 5V. It is most likely a wiring problem.

Elco or anyone else for that matter

I’m sorry if I seem like a pest on this but could you please explain in more simple terms what you want me to do? As stated earlier, I’m not very familiar with the technical stuff here. I was able to build and install the brewpi based off of your step by step guide. But I don’t know what you mean or how to do it when you suggest taking out the OneWire board and plugging the snsors into the shield directly. Do you happen to have a simple diagram/pictures/video of what you’re asking?

Remember, I did complete 2 ferments with the setup previously, so I would think it’s not a wiring issue.

Thanks in advance for your patience and help.


Do you mean to unplug the sensor from here:

And plug it directly into here?


Yes, that is exactly what I mean. That way, you can eliminate the wiring to the distribution board form the error checking process. But always check your wire colors and the text on the board before plugging them in.

Ok so I tested all 4 probes one at a time and only 1 of them was detected when I placed it into the shield directly. They’re all the same wire color and they all are wired exactly the same. And the connections are solid, with no insulation being in the way. Is this a case of 3 of my 4 probes are bad?

That does not sound likely, unless you have connected the wires wrong previously. This will fry the probes and they will feel warm to the touch.

BTW, a better way of connecting the pluggable terminals that I discovered after making the guide is to just fold back the wire strands over the isolation and then screw it into the cage clamp. That way the isolation works as a strain relief too.

Will the probes feel warm even still now when I plug them in? or would frying them ruin them completely after the first “feels warm” moment? also what should the read value be for the probe that does work? Mine showed 20.something

I ordered a 5 pack of new probes off amazon overnight delivery.


I’m hoping I can get this resolved tomorrow and brew friday after work. The wire colors are different but they’ve got them labeled on the the sale page, so it shouldn’t be too difficult to match the colors with the correct terminal slots.

Ok so I got the new probes today. Wired them per the instructions found in the brewpi case assembly guide. When I plug them directly into the arduino shield I can detect them. When I plugged the one wire board back into the arduino shield I can’t detect any of them and one of the probes got hot to the touch. I checked both arduino’s that I have with the same result.

Upon further review. I noticed that one of my connecting cables that connect the one wire board to the arduino shield was wired wrong. Could this have ruined the one wire boards?

The one wire board is just a breakout board so no. You may may have damaged all of your sensors though.

Also, If i did fry the one wire boards can I just connect 2 sensors into the same terminal and insert that terminal into the arduino shield?

Ok but if I can detect each sensor by plugging directly into the arduino why can’t I detect them on the one wire board with a properly wired connection?

Either there is a dodgy connection or there is a short on the OneWire board. There is no electronics on the OneWire board, just the 5 connectors in parallel. Yes you can simply stick multiple sensors into the same connector on the shield.



That worked…both sensors detected and installed…WOOHOO

Please note that the sensor board is on the bottom is just 3 straight traces.
One side connector has the right pin order, the other side has not! So please carefully note the text on the board before plugging in. I should have designed that differently, I know.