#585 DS1822 1-Wire Reading
Basic interrogation of a DS1822 using 1-wire protocol and results display on a Nokia 5110 LCD.
Notes
The DS1822 is an economy 1-Wire digital thermometer with a range of -55°C to +125°C, at ±2.0°C Accuracy from -10°C to +85°C.
It comes in TO-92 packaging and may be powered directly (using three pins), or take parasitic power from the data line (using two pins).
Basic Operation
The sequence of operations boils down to this:
- Send a search request on the wire to find a device
- Get the device address and ensure the family code is as expected
- Issue conversion command (0x44)
- Wait for conversion, then read the conversion scratchpad from the device
- Process the data received
Family Codes
| Model | Code |
|---|---|
| DS18S20 | 0x10 |
| DS18B20 | 0x28 |
| DS1822 | 0x22 |
Construction
The Program
The Arduino sketch is found in DS1822.ino. It uses:
- OneWire library for temperature sensor communication
- u8glib library for driving a simple display on a Nokia 5110 screen.
The sketch was written to work with the DS1822, but it can also handle DS18S20 and DS18B20 devices.