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