DallasTemperature Library
Library for Maxim Temperature Integrated Circuits.
This library supports the following devices :
- DS18B20
- DS18S20 - Please note there appears to be an issue with this series.
- DS1822
- DS1820
- MAX31820
You will need a pull-up resistor of about 5 KOhm between the 1-Wire data line and your 5V power. If you are using the DS18B20, ground pins 1 and 3. The centre pin is the data line '1-wire'.
In case of temperature conversion problems (result is -85), strong pull-up setup may be necessary. See section Powering the DS18B20 in DS18B20 datasheet (page 7) and use DallasTemperature(OneWire*, uint8_t) constructor.
We have included a "REQUIRESNEW" and "REQUIRESALARMS" definition. If you want to slim down the code feel free to use either of these by including
#define REQUIRESNEW
or
#define REQUIRESALARMS
at the top of DallasTemperature.h
Finally, please include ZUNO_OneWire.h before you begin.
The library can work with any pin it works with Zuno OneWire see Zuno OneWire about this and the peripherals used.
// Include the libraries we need
#include "ZUNO_OneWire.h"
#include "DallasTemperature.h"
#define MY_SERIAL Serial
#define ONE_WIRE_BUS 9
// Setup a oneWire instance to communicate with any OneWire devices (not just Maxim/Dallas temperature ICs)
OneWire oneWire(ONE_WIRE_BUS);
// Pass our oneWire reference to Dallas Temperature.
DallasTemperature sensors(&oneWire);
// arrays to hold device address
DeviceAddress insideThermometer;
/*
* Setup function. Here we do the basics
*/
void setup(void) {
// start serial port
MY_SERIAL.begin(115200);
MY_SERIAL.println("Dallas Temperature IC Control Library Demo");
// locate devices on the bus
MY_SERIAL.print("Locating devices...");
sensors.begin();
MY_SERIAL.print("Found ");
MY_SERIAL.print(sensors.getDeviceCount(), DEC);
MY_SERIAL.println(" devices.");
// report parasite power requirements
MY_SERIAL.print("Parasite power is: ");
if (sensors.isParasitePowerMode()) MY_SERIAL.println("ON");
else MY_SERIAL.println("OFF");
// Assign address manually. The addresses below will beed to be changed
// to valid device addresses on your bus. Device address can be retrieved
// by using either oneWire.search(deviceAddress) or individually via
// sensors.getAddress(deviceAddress, index)
// Note that you will need to use your specific address here
//insideThermometer = { 0x28, 0x1D, 0x39, 0x31, 0x2, 0x0, 0x0, 0xF0 };
// Method 1:
// Search for devices on the bus and assign based on an index. Ideally,
// you would do this to initially discover addresses on the bus and then
// use those addresses and manually assign them (see above) once you know
// the devices on your bus (and assuming they don't change).
if (!sensors.getAddress(insideThermometer, 0)) MY_SERIAL.println("Unable to find address for Device 0");
// method 2: search()
// search() looks for the next device. Returns 1 if a new address has been
// returned. A zero might mean that the bus is shorted, there are no devices,
// or you have already retrieved all of them. It might be a good idea to
// check the CRC to make sure you didn't get garbage. The order is
// deterministic. You will always get the same devices in the same order
//
// Must be called before search()
//oneWire.reset_search();
// assigns the first address found to insideThermometer
//if (!oneWire.search(insideThermometer)) MY_SERIAL.println("Unable to find address for insideThermometer");
// show the addresses we found on the bus
MY_SERIAL.print("Device 0 Address: ");
printAddress(insideThermometer);
MY_SERIAL.println();
// set the resolution to 9 bit (Each Dallas/Maxim device is capable of several different resolutions)
sensors.setResolution(insideThermometer, 9);
MY_SERIAL.print("Device 0 Resolution: ");
MY_SERIAL.print(sensors.getResolution(insideThermometer), DEC);
MY_SERIAL.println();
}
// function to print the temperature for a device
void printTemperature(DeviceAddress deviceAddress) {
// method 1 - slower
//MY_SERIAL.print("Temp C: ");
//MY_SERIAL.print(sensors.getTempC(deviceAddress));
//MY_SERIAL.print(" Temp F: ");
//MY_SERIAL.print(sensors.getTempF(deviceAddress)); // Makes a second call to getTempC and then converts to Fahrenheit
// method 2 - faster
float tempC = sensors.getTempC(deviceAddress);
if(tempC == DEVICE_DISCONNECTED_C) {
MY_SERIAL.println("Error: Could not read temperature data");
return;
}
MY_SERIAL.print("Temp C: ");
MY_SERIAL.print(tempC);
MY_SERIAL.print(" Temp F: ");
MY_SERIAL.println(DallasTemperature::toFahrenheit(tempC)); // Converts tempC to Fahrenheit
}
/*
* Main function. It will request the tempC from the sensors and display on MY_SERIAL.
*/
void loop(void) {
// call sensors.requestTemperatures() to issue a global temperature
// request to all devices on the bus
MY_SERIAL.print("Requesting temperatures...");
sensors.requestTemperatures(); // Send the command to get temperatures
MY_SERIAL.println("DONE");
// It responds almost immediately. Let's print out the data
printTemperature(insideThermometer); // Use a simple function to print out the data
}
// function to print a device address
void printAddress(DeviceAddress deviceAddress) {
for (uint8_t i = 0; i < 8; i++) {
if (deviceAddress[i] < 16) MY_SERIAL.print("0");
MY_SERIAL.print(deviceAddress[i], HEX);
}
}