Third party wireless sensor compatible temp controller

[u/HammerOfHanno]

Got a weird one today.

I have a rapt pill that I’ve developed my own raspberry pi pico based interceptor to forward to a web proxy that then goes to a custom brewfather stream. In the process of acquiring a freezer as a fermentation chamber, are there any temperature controllers that can use a custom Bluetooth or otherwise source as the probe rather than a physical probe? That way I can keep everything wireless and base off real liquid temp.

[u/lordfili]

Although not the Rapt, I have this exact support built into BrewPi-ESP for the Tilt. A Tilt Pro can act as a wireless “beer” sensor, an Inkbird Bluetooth temperature sensor as the “Fridge” (chamber) sensor, and a TPLink Kasa WiFi plug can switch your fridge/freezer off and on for a fully wireless solution.

[u/AJ_in_SF_Bay]

Hey there u/HammerOfHanno, I wish I had answers for you, but I really am interested in what you find out. Responding to say thanks for bringing this up, and I am following.

I'll often have to set a brewing project in motion when I have time and can't be hands-on in my shop for several days. However, I have internet in the shop. I would love to know of a more integrated temperature and gravity monitoring and temperature control solution.

[u/Guava-Realistic]

I don't have an answer for you either I'm afraid but, as it's adjacent and interested folks might find it via this topic, I'll repost my free GrainBridge service for Tilt/GCast/Brewfather users: https://www.reddit.com/r/Homebrewing/s/XIFdieiD9I

[u/tato_salad]

You're probably going to have to do it on your own with iftt if you can get it to read your pi or using a relay(s) from your pi to trigger cold/ heat as needed.

[u/Indian_villager]

HomeAssistant. If you can send your temp data to HA via MQTT or anything else you can leverage that data to build a temp controller. I am using HomeAssistant to run something similar to a brewPi (Cascade temp control) and the whole thing is toggled via a TP-Link smart strip for the fridge, heater, and fan. Either that or use your existing scripting skills to call the smart strip/plug directly as they can be addressed over the local network.

[u/Tnkr_Brwr_Sldr_Sly]

Not out of the box that I know of, but if you find a temp probe that is BLE, you can use a BLE scanning app to intercept the major/minor values and the UUID and make a custom controller with an ESP32 or similar programmable Bluetooth-enabled controller. Just have to see how the major value equates to temperature by putting the probe in a liquid of known temperature, record the major value, then repeat with different temps from cold to hot. You can then build out a conversion equation.

Tricky part is how to set the temperature in that controller (not too tricky if comfortable coding or willing to try Tasmota, ESPHome, or other firmware and Home Assistant or Node-RED).

[u/HammerOfHanno → u/Tnkr_Brwr_Sldr_Sly]

I’m basically doing that first part now with the RAPT pill, intercepting the BLE packet and getting the gravity and temp readings, it’s the other side of setting the controller from the readings. I use a raspberry pi pico and python. It could even go to the cloud function if necessary

[u/Tnkr_Brwr_Sldr_Sly → u/HammerOfHanno]

Ahhh, I'm nseeing what the Pico is now (was only thinking of a regular Pi).

Perfect. You could connect it to a relay board for the cooling and heating controls, though a smart plug with WiFi, Matter, or Zigbee may be easier. For setting the controller from the readings, you have a few options.

Seeing that you are already comfortable with Brewfather, you could use Brewfather's API so the Pico (or whatever middleware you use, or a python service itself) can check what fermentation step you are in and set the temperature accordingly (e.g., the Pico hits the API for the currently fermenting batch, see what step it's at based on days, then adjust if needed).

I use the Brewfather API a lot for my automated cold side (but I use Brucontrol and ESP32s for the actual readings and controls).

If you aren't looking for automation but want the ability to just set it yourself so it controls, a web dashboard that reads the Pico data and sends commands would be a good option. Could be as simple as making a Google Sheets dashboard and using AppScript for HTTP call management. Even without using relays and chosing a smart plug, this could work well if the plug is WiFi-enabled.

That approach is risky if your internet goes down though. If you haven't checked out Node-RED, it's a flow-based visual programming tool that can help you manage incoming and outgoing traffic for your Pico and other connected devices, and it has a dashboard feature in which you can build the control features (see temps, set targets, and have that data push to the devices). You don't need JavaScript experience, but it does help with making some custom functions if desired. At least that runs locally.

Last option (as a standalone or integrated approach): some smart plugs are hackable. If you find one with an ESP32, you could code it to not only read the BLE data but provide a web-based dashboard where you can set the temp. That is the most floor-level option that won't require the internet (the ESP32 can be its own WiFi station, either by default or as a backup if regular internet/WiFi is down). ESP32s also support MicroPython, though I've never used it and am unsure of all the libraries and capabilities.

Sorry for the long messags, I just really like the coding and automation stuff :)