766 B
766 B
Wiring
Sensors
DS18B20 pinout:
| PIN | Use |
|---|---|
| 1 | VDD |
| 2 | GND |
| 3 | DQ |
Notes
Solid state relays
The SSRs draw 5-7 mA when supplied with 3.3 V.
RPi
A maximum of 16 mA per pin with the total current from all pins not exceeding 51 mA.
DS18B20
A DS18B20 temperature sensor draws up to 1.5 mA. It requires approx. 750 ms to convert at 12-bit resolution.
The DQ line must be pulled up by a 4.7 kohm resistor and connected to GPIO4.
The kernel needs to be configured via /boot/config.txt:
dtoverlay=w1-gpio-pullup,gpiopin=4
1-Wire drivers need to be loaded in order to create the connection between the physical sensor and the rPI.
modprobe wire
modprobe w1-gpio
modprobe w1-therm