KY-001 Temperature sensor (DS18B20)

// Required libraries will be imported
#include <OneWire.h>
#include <DallasTemperature.h>            

// Here the input pin is declared to which the sensor module is connected
#define KY001_Signal_PIN 4

// Libraries are configured
OneWire oneWire(KY001_Signal_PIN);          
DallasTemperature sensors(&oneWire);    


void setup() {

    // Initialize serial output
    Serial.begin(9600);
    Serial.println("KY-001 temperature measurement");

    // Sensor is initialized
    sensors.begin();  
}

//main program loop
void loop()
{
    // Temperature measurement is started...
    sensors.requestTemperatures();
    // ... and output measured temperature
    Serial.print("Temperature: ");
    Serial.print(sensors.getTempCByIndex(0));
    Serial.println(" °C");

    delay(1000); // 1s pause until next measurement
}

The DS18B20 is a digital thermometer that can measure temperature in Celsius. It offers different accuracy levels from 9 to 12 bits. This means that it can provide very accurate measurements, with a higher bit count providing a more accurate temperature measurement. The measuring range of the DS18B20 is between -55°C and +125°C, and the accuracy is ±0.5°C in the range from -10°C to +85°C.

The DS18B20 uses a so-called 1-wire bus to communicate with a microprocessor. This means that only a single data line is needed to exchange information. The sensor can even draw its power from this data line, so no additional power source is required. This mode of operation is called "parasite power".

Each DS18B20 sensor has a unique 64-bit serial code. This is like a unique identification number for each sensor. This means that several DS18B20 sensors can be connected to the same 1-Wire bus and still be individually recognized and read out. This makes it easy to implement networks with multiple sensors.

This sensor is particularly useful in many applications, such as in heating, ventilation and air conditioning (HVAC) systems, for temperature monitoring in buildings or machines and in process monitoring and control systems. Other applications include medical devices, industrial control systems and temperature monitoring in cooling systems.

In summary, the DS18B20 offers a precise and flexible solution for temperature measurement with simple cabling and the possibility of integration into complex systems with multiple sensors.

Technical Data
Chipset	DS18B20
Communication Protocol	1-Wire
Accuracy	9 to 12 Bit
Measuring range	-55 °C to +125 °C
Measurement accuracy	±0.5 °C from -10 °C to +85 °C

Pin assignment

Raspberry Pi	Sensor
GPIO4 [Pin 7]	Signal
3.3 V [Pin 1]	+V
GND [Pin 6]	GND

Code-Example

To enable the Raspberry Pi to communicate with the DS18B20 sensor via the one-wire bus, it must first be activated. To do this, enter the following command:

sudo raspi-config

Now go to Interface Options and activate the 1-Wire interface. Your Raspberry Pi should then restart automatically. Or you can use the following command to restart manually:

sudo reboot

You can now use the following example. A console output is generated as soon as a signal is detected.

This is an example program that outputs the measured temperature serially after the sensor has been initialized.

# SPDX-FileCopyrightText: 2019 Mikey Sklar for Adafruit Industries
#
# SPDX-License-Identifier: MIT

import glob
import time

base_dir = '/sys/bus/w1/devices/'
device_folder = glob.glob(base_dir + '28*')[0]
device_file = device_folder + '/w1_slave'

def read_temp_raw():
	f = open(device_file, 'r')
	lines = f.readlines()
	f.close()
	return lines

def read_temp():
	lines = read_temp_raw()
	while lines[0].strip()[-3:] != 'YES':
		time.sleep(0.2)
		lines = read_temp_raw()
	equals_pos = lines[1].find('t=')
	if equals_pos != -1:
		temp_string = lines[1][equals_pos+2:]
		temp_c = float(temp_string) / 1000.0
		temp_f = temp_c * 9.0 / 5.0 + 32.0
		return temp_c, temp_f

while True:
	print(read_temp())
	time.sleep(1)

Example program download

KY001-RPi.zip

Start with the command:

sudo python3 KY001-RPi.py

	
		basic.forever(function () {
		    serial.writeValue("temp ", DS18B20.TemperatureNumber(DS18B20.pin.pin1))
		    basic.pause(1000)
		    serial.writeLine("temp : " + DS18B20.TemperatureString(DS18B20.pin.pin1))
		    basic.pause(1000)
		    basic.showNumber(DS18B20.TemperatureNumber(DS18B20.pin.pin1))
		    basic.pause(100)
		})
	

# Load libraries
import machine, onewire, ds18x20
from time import sleep

# Initialization of GPIO2
ds_pin = machine.Pin(10)

# Initialization of the sensor object
ds_sensor = ds18x20.DS18X20(onewire.OneWire(ds_pin))

# Search for all matching sensors
roms = ds_sensor.scan()

# Serial output
print("Found DS devices")
print("Temperature (°C)")

# Endless loop for continuous reading of the temperature
while True:
  ds_sensor.convert_temp()
  sleep(1)
  # Based on the number of compatible sensors found it will count up
  for rom in roms:
    # Serial output of the measured temperature
    print(ds_sensor.read_temp(rom))
  sleep(3)