Note: the jar is sitting on a container of water as a thermal load, I wouldn't put it directly on the heat mat
I used an Arduino Diecimila but you should be able to use any Arduino really, like an UNO or Nano.
An even better solution is using a SparkFun Qwiic Pro Micro which gives you I2C over their QWIIC connector making it very easy to add a Digital Temperature Sensor or an OLED Display or all sorts of other stuff using QWIIC or Adafruit STEMMA, See this page for more info.
This uses Docker to run ino to build and upload the code to the Arduino.
I used digital pin 2 for the sensor and pin 7 for the relay
To change the Arduino hardware type, see the ino.ini file
To change the USB port, see the upload.sh also
First run the build the docker image
./build.sh
then upload code to th Arduino (it should be connected to a USB port)
./upload.sh
You can install minicom and connect to the console to see the current values of the sensor
minicom -D /dev/ttyUSB0 -b 9600
Welcome to minicom 2.7.1
OPTIONS: I18n
Compiled on May 6 2018, 08:02:47.
Port /dev/ttyUSB0, 00:46:48
Press CTRL-A Z for help on special keys
AM2302 Humidity - Temperature Sensor
RH Temp (C) Temp (F) Heat Index (C) Heat Index (F) Power state
54.60 % 23.60 *C 74.48 *F 25.18 *C 77.33 *F 0
54.60 % 23.60 *C 74.48 *F 25.18 *C 77.33 *F 0
54.60 % 23.60 *C 74.48 *F 25.18 *C 77.33 *F 0
...
47.70 % 23.20 *C 73.76 *F 25.15 *C 77.26 *F 1
47.30 % 23.20 *C 73.76 *F 25.15 *C 77.27 *F 1
47.20 % 23.10 *C 73.58 *F 25.13 *C 77.23 *F 1
...
49.40 % 24.80 *C 76.64 *F 25.77 *C 78.38 *F 0
49.40 % 24.80 *C 76.64 *F 25.77 *C 78.38 *F 0
49.40 % 24.80 *C 76.64 *F 25.77 *C 78.38 *F 0
Tip: use control+a, then z, then x to exit minicom on OSX
The code will try to keep the temp between 74F and 76F (it will go slightly higher realistically, like 78*F), you can tweak that in the sketch.ino if you want, but should be good for bread and other ferments.
Hardware:
References:
- arduino-delivery-container
- Arduino Power – DLI IoT Power Relay
- Arduino AM2302 hookup
- DHT11 DHT22 Arduino tutorial - has LCD code if interested in that