DS18B20 convenient digital thermal sensor. In industrial operation, sensors are usually used in a waterproof stainless steel capsule. Sensor Characteristics:
- The Range of measured temperatures is 55 ° ~ + 125 °.
- Supply Voltage 3.0 V ~ 5.5 V
- Low Cost (~ 1.3 USD)
- Single-Wire interface 1Wire.
- Accuracy ± 0.5 °C in the range of-10 °C to + 85 °C.
- Programmable resolution from 9 Bits to 12 Bits.
- Unique 64-bit serial number for each sensor eliminates conflicts on one bus.
- It Is possible to connect directly to microcontrollers without additional converters.
Sensor Outputs in stainless steel: Red (VCC), yellow (DATA), Black (GND)
The wiring Diagram is very simple. The Sensor is connected to the digital input via the resistor 4.7 K on + power supply.
I purchased sensors in metal waterproof capsules wholesale, 10 pcs. This seller on Aliexpress. Price ~ 1.3 USD per piece. With operative delivery to Russia. If the delivery time is not critical, the sensor can be ordered at a price of about 1 USD from many sellers on Aliexpress with free shipping.
Retrieving DS18B20 sensor addresses
#include < OneWire. h.
OneWire DS (15); Data wire connected to GPIO15
void Setup (void) {
Serial. Begin (9600);
}
void loop (void) {
byte I;
BYTE addr[8];
if (! ds. Search (addr)) {
Serial. println ("No more addresses.");
Serial. println ();
ds. Reset_search ();
Delay (250);
Return
}
Serial. Print ("ROM =");
for (i = 0; i < 8; i + +) {
Serial. Write (' ');
Serial. Print (add[i]r, HEX);
}
}DS18B20 sensor Survey
#include < OneWire. h.
#include < DallasTemperature. h.
Data wire is connected to GPIO15
#define ONE_WIRE_BUS 15
Setup a oneWire instance to communicate with a OneWire device
OneWire oneWire (ONE_WIRE_BUS);
Pass our oneWire reference to Dallas Temperature sensor
DallasTemperature Sensors (& oneWire);
DeviceAddress Sensor1 = {0x28, 0xB1, 0x13, 0x46, 0x92, 0xD, 0x2, 0xA7};
void Setup (void)
{
Serial. Begin (115200);
Sensors. Begin ();
}
void loop (void)
{
Serial. Print ("Requesting temperatures...");
Sensors. requestTemperatures (); Send the command to get temperatures
Serial. println ("DONE");
Serial. Print ("Sensor 1:");
Serial. Print (String (sensors. getTempC (Sensor1)) + "C,");
Serial. println (String (sensors. getTempF (Sensor1)) + "F");
tempSensor. requestTemperaturesByIndex (0);
Get Single sensor value
Serial. Print ("Temperature:");
Serial. Print (sensors. getTempCByIndex (0));
Serial. Print ("C,");
Serial. Print (sensors. getTempFByIndex (0));
Serial. println ("F");
Delay (1000);
}If more than one sensor hangs on the same bus, the code will be somewhat more complex. In this case, two DS18B20 sensors connected to the GPIO32 microcontroller ESP32 are tested.
#include "OneWire_Scanner. H"
#include < OneWire. h.
#include < DallasTemperature. h.
#define OneWire_PIN 32
OneWire DS (OneWire_PIN);
Pass our oneWire reference to Dallas Temperature sensor
DallasTemperature Sensors (& DS);
Count of DS18xxx Family devices on bus
uint8_t devices = 0; Reset the number of devices when we enumerate wire devices
uint8_t ds18Count = 0; Reset number of DS18xxx Family devices
void Setup ()
{
Sensors. Begin ();
ScanOneWireDevicesAndShowTemp ();
Output the total number of found devices
Serial. println ("Foun[" + String(ds18Count) + "]d DS18XXX sensors of[" + String(devices) + "] iWare devices.");
Serial. Print (sensors. getDeviceCount (), DEC);
Serial. Print (sensors. getDS18Count (), DEC);
Check how the power is connected
Serial. Print ("Parasite power is:");
Serial. println (sensors. isParasitePowerMode ()? "ON": "OFF");
}
void Loop ()
{
ScanOneWireDevicesAndShowTemp ();
Delay (1000);
}
String getSensorModel (uint8_t modelByte)
{
deviceAddress[0]
String res = "";
Switch (modelByte)
{
Case DS18S20MODEL:
return "DS18S20";
Case DS18B20MODEL:
return "DS18B20";
Case DS1822MODEL:
return "DS1822";
Case DS1825MODEL:
return "DS1825";
Case DS28EA00MODEL:
return "DS28EA00";
default:
return "Unknown";
}
}
void ScanOneWireDevicesAndShowTemp ()
{
DeviceAddress deviceAddress;
while (ds. Search (deviceAddress))
{
if (sensors. validAddress (deviceAddress))
{
bitResolution = max (bitResolution, sensors. getResolution (deviceAddress));
Devices + +;
if (sensors. validFamily (deviceAddress))
{
Sensors. requestTemperatures (); Send the command to get temperatures
Serial. Print ("Sensor");
printAddress (deviceAddress);
Serial. println (". Temp: "+ String (sensors. getTempC (deviceAddress)) +" oC with resolution "+ String (sensors. getResolution (deviceAddress)) +" bit. Sensor "+ getSensorModel (deviceAddress[0]) +". ");
ds18Count + +;
}
}
}
}
void printAddress (DeviceAddress deviceAddress)
{
for (uint8_t i = 0; i < 8; i + +)
{
if (deviceAddress[i] < 16) Serial. Print ("0");
Serial. Print (deviceAddres[i]s, HEX);
}
}The Result of the DS18B20 Sensor Survey code:
11:42:18.863-> Sensor 28B11346920D02A7. Temp: 24.19 oC with resolution 12 bit. Sensor DS18B20. 11:42:18.999-> Sensor 28FF6C7997090341. Temp: 28.12 oC with resolution 12 bit. Sensor DS18B20. 11:42:20.022-> Found[2] DS18XXX sensors of[2] iWare devices. 11:42:20.022-> Parasite power is: OFF
