How to Use a Johnson Temperature Controller in Combination with a Ferawrap - Probe conflict with Raspberry PI

I received the Johnson A419 Digital Temperature Controller and will be getting a Fermwrap today in the mail (and I will be brewing tonight hopefully).

I noticed that the Johnson model comes with a probe. Do I sanitize this probe and place it through the airlock into my wort?

I currently use a Raspberry Pi with DS18B20 temperature probes to monitor the temperature of my wort, which I store in a database. I sanitize these probes and place it through the airlocks into my wort.

I would not be able to fit both the DS18B20 and the Johnson probe through the airlock as the diameter isn't big enough.

Must I sacrifice my statistical experiment to accomodate the Johnson probe?

On the other hand, is there a way for me to put the Johnson probe through the airlock and then read send the temperatures from the Johnson Control to my Raspberry Pi (Or first to my Arduino and then to my RPi)?

Any ideas?

Topic temperature-probe temperature-control homebrew

Category Mac

1
answered at

AFAIK, the Johnson probes are not waterproof, so you should not place them into the wort/beer. Either get a thermowell so you can read the temp of the beer itself (ideal), or tape the probe to the outside of the carboy. If you do that latter, you can continue to use your RPi recording approach on this brew.

Going forward, you have a number of options…

1/ Extend the RPi to drive a relay to drive the fermwrap, and use that to obsolete the Johnson A419.

2/ Drop two thermowells into the carboy so you can both control (via A419) and record (via DS18B20+RPi).

3/ As you say, try to read the temps off the A419's probe.

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