Thermometer Setup
CraftbeerPi uses DS1820/DS18B20/DS18S20 thermometer sensors.
Several sensors is supported, upto 10 can be shown on the control window.
The sensor have three terminals:
- Supply voltage : 5 Volt (usually RED wire color)
- DQ: data line (usually WHITE or YELLOW wire color)
- Ground (usually BLACK wire color, Blue seen also)
A 4,7 kilo ohm pull-up resistor is required, from 3.3V to the DQ : data line.
The Raspberry PI uses GPIO4 for the data bus for the temperature sensors. (For CHIP, LCD-D2 is used.)
The sensor(s) is usually mounted inside a thermowell mounted in the kettle. (Thermowell example)
Thermowell for Fermentation example
In case fermenting mode is used, it is mounted in the fermenter or fridge.
Note that thermal grease in the thermowell will help to qucikly let temperature changes in the kettle to be detected, so this makes the regulation better/faster. But it can be omitted.
During installing CraftBeerPI you are asked if you want to install One-wire support. You must say "yes" for the temperature sensor bus to be enabled. If you forgot, reinstall CBP or look in troubleshooting section of this wiki.
Note: In CraftbeerPI Hardware sensor menu : do not leave the offset blank, set it to 0. (if you leave blank , the temperature may not be displayed)
Check if the temperature sensors are found by the Raspberry Pi OS.
For each sensor a folder get created under /sys/bus/w1/devices on the Raspberry Pi. The folder name is the sensor id. This way you can see if the connected sensor(s) work.
All sensors is connected on the same bus, so if one sensor is defect it can cause all sensors on the bus to fail. So test you're sensors one at the time to find a faulty one. When you know you have all good ones, connect them together.
Keep Mains power cables away from the thermometer sensors/cables. The reason is that Mains will interfere with the digital signals running on the temperature sensors.
- 0 = data line or GND missing. Check connection
- 85 = internal sensor error. Maybe the cable is too long
- -127 = No supply voltage. Missing VSS