Preparing wine with IoT sensors

Every wine producer needs to know their temperature during fermentation. There are many small producers (like in our family) without high-end equipment for fermenting the grapes and must. We produce wine for our own use (around 1000 litres) and the technology relies mostly on experience and limited information about the fermentation process.  One of the most important paramters is temperature or more specifically, the temperature profile (time dependance), its gradient and maximum value as well. In the past I connected simple I2C sensor to raspberry pi and sent data to mysql database via WiFi connection. It is shame to mention the power consumption of such thermometer.

Loradunchy module on top of the low cost solar cell

Recently, I placed LoRaWAN gateway at the top of the vineyard to cover all future need for connecting winegrowing sensors in all neighbouring vineyards. The r.pi thermometer was upgraded to LoRa and I used my own design, the LoRaDunchy module with small LiPo battery, TMP75 as sensor element and small solar cell for supplying the power. Solar power is somehow overkill for this application, but I want to check the real life solar powered sensor. It would be good experience for future sensors which I intend to place in the field for monitoring the microclimatic conditions (and possible prediction of the vine diseases).

LoraDunchy Connection diagram for thermometer application

The thermometer chip is TMP75. It is digital temperature sensor with I2C interface and up to 27 different I2C addresses (with only 3 pins). The TMP75 offers a typical accuracy of ±1°C without requiring calibration or external component signal conditioning, which makes it very “arduino style” to use.

The sensor is placed inside aluminium tube for easier placement inside fermetning fruit mixture. The tube is closed with (what else) cork:

Grape juice colored the cork red

The cable side is good to close to avoid sour juice (conductive ion rich mixture) entering inside the tube and destroying the sensor:

Cable side of the sensor is closed with another piece of cork

The solar power is used to charge the battery during daytime:

Solar panel (cheap one from ebay with 5V USB output)

The thermometer end node project is published on GitHub:


to use this code you should clone complete Loradunchy repository and prepare the comissioning file based on provided template and specific data from your TTN registered device.

The data from TTN is sent via HTTP integration to my NodeRed server. The readouts are stored there in the database where Grafana (on same server) present is in fancy diagrams. The Grafana is also used to trigger the alarms and notifications.

Loradunchy module itself provides the battery fuel gauge measurements via STC3100. There is Li-xx charger on board as well. To operate the module, just connect the 5V via on-board micro USB. The battery charging is shown in the diagrams below:

Battery current during the charge cycle

Relative state of charge (in mAh) during the charging cycle

Such diagrams above are very technical for average hobby producer of the wine.

What is much more important is temperature diagram:

Fermentation temperature profile during hand mixing in the evening

The temperature rised above alarm value (24°C) for specific time (10 minutes). This triggered alarm via email to the owner of the small cellar. Hw then went there and hand mixed the 500 liter container with fermenting grapes and added few bottles of ice. The temperature  then droped significantly and the slow fermenting process continues. The quality of young wine should be excellent.



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