DS18B20 Temperature Heat Sensor

DS18B20 Temperature Heat Sensor

Digital Thermometer IC -55C 125C  TO-92 +-0.5C Accuracy 9/12 Bit ADC 1 Wire Communication DS1820

     The DS18B20 is a digital temperature sensor supplied as a bare IC, without cable, in a 3-pin TO-92 package. It measures from -55°C to +125°C; between -10°C and +85°C its accuracy is ±0.5°C (chip manufacturer data). Resolution is selectable between 9 and 12 bits; at 12 bits a measurement with 0.0625°C steps takes at most 750ms. It is powered from 3.0V - 5.5V and outputs the result digitally over a single data line (1-Wire); no analog reading or calibration is required.

     Every DS18B20 contains a unique 64 bit serial number. Thanks to this, several sensors are connected in parallel to the same data line and each is read separately by its address; a single control pin is enough for multi-point measurement. The only extra part needed to run the line is a 4.7k pull-up resistor. The chip has upper and lower alarm limits stored in non-volatile (EEPROM) memory.

     The TO-92 package is soldered to a through-hole PCB or plugged directly into a breadboard; it is placed on your own circuit board, inside a device, or at a heatsink or surface to be measured. For measurement in liquids, waterproof probe versions of this chip with 1 metre and 5 metre cable are sold separately.

Key features:

     Calibration-free digital reading: It outputs temperature directly as a digital value; no analog reading, converter or user calibration is needed. ±0.5°C accuracy between -10°C and +85°C (chip manufacturer data).

     Many sensors on one line: Thanks to the unique 64 bit serial number, several DS18B20s connect to the same data line; multi-point measurement is done with one pin and one pull-up resistor on the control board.

     Wide measuring range: It measures from -55°C to +125°C; it is used in a wide range from freezers to power electronics heatsinks.

     Selectable resolution: Selectable between 9 - 12 bits. 0.0625°C steps and at most 750ms at 12 bits, at most 93.75ms measuring time at 9 bits; speed or precision is set as needed.

     Small TO-92 package: The small 3-pin body is soldered to a PCB or plugged into a breadboard; it fits narrow places, circuit boards and device interiors.

Features:

• Product type:    Digital temperature sensor IC (bare chip, without cable)
• Model: DS18B20 (body marking "DALLAS 18B20", product image)
• Measuring range: -55°C to +125°C
• Accuracy: ±0.5°C (between -10°C and +85°C, chip manufacturer data)
• Resolution: selectable between 9 - 12 bits (0.0625°C steps at 12 bits)
• Conversion time: at most 750ms at 12 bits, at most 93.75ms at 9 bits
• Communication: 1-Wire (single data line), only a 4.7k pull-up resistor as extra component
• Addressing: unique 64 bit serial number; several sensors on the same line
• Supply voltage: 3.0V - 5.5V (normal 3-pin supply recommended)
• Current: typical 750nA in standby, 1mA - 1.5mA during measurement
• Parasite power: according to chip data, power can be taken from the data line (VDD pin to GND)
• Alarm: non-volatile (EEPROM) user-set upper / lower temperature alarm
• Compatible boards: Arduino, ESP32, ESP8266, Raspberry Pi, STM32 and all boards that can read 1-Wire
• Pinout: flat face towards you, leads down, from left to right 1 GND, 2 DQ (Data), 3 VDD
• Mounting: soldering to a through-hole PCB or plugging into a breadboard
• Package and material: TO-92, black plastic body, 3 metal leads
• Dimensions: body about 5mm x 4mm x 5mm (excluding leads)
• Weight: about 0.2gr

Usage information:

• With the flat face towards you and the leads down, connect the left lead to GND, the middle lead (DQ) to a digital pin of the board and the right lead (VDD) to the 3.3V or 5V supply.
• Connect a 4.7k pull-up resistor between the DQ lead and the logic voltage of the board: 5V on Arduino Uno/Nano, 3.3V on ESP32, ESP8266 and Raspberry Pi (power the sensor from 3.3V on these boards too). Without the resistor the sensor cannot be read (-127°C is shown).
• Choose the resolution as needed: at 12 bits a measurement with 0.0625°C steps takes at most 750ms, at 9 bits at most 93.75ms; do not make the reading interval shorter than this time.
• You can connect several sensors in parallel to the same DQ line; a single pull-up resistor is enough and each sensor is read separately by its 64 bit address.
• When measuring a surface or heatsink, put the flat face of the body in contact with the measured surface and apply thermal paste between them and fix it with a clamp or adhesive.

Areas of use:

•  Incubator temperature control
•  Thermostat and room temperature control circuits
•  Fan control: running a cooling fan according to temperature
•  Greenhouse and plant growing air temperature
•  Refrigerator and deep freezer interior temperature monitoring
•  Fermentation cabinet ambient temperature monitoring
•  Datalogger and weather station
•  Power supply, motor driver and heatsink temperature monitoring
•  Adding temperature measurement to your own circuit board
•  Education and STEM projects with Arduino and Raspberry Pi
   

Precautions:

•  The TO-92 package is not waterproof. For measurement in wet environments such as water, aquariums or soil use the waterproof cabled probe version.
•  Do not apply power without checking the pinout; if GND and VDD are reversed the chip heats up quickly and fails.
•  The sensor cannot be read without a pull-up resistor on the DQ line. On 3.3V logic boards connect the resistor to 3.3V, not 5V; a line pulled to 5V can damage a 3.3V pin.
•  Parasite power (VDD pin to GND, power from the data line) does not work reliably with clone chips. Connect the VDD pin to a 3.0V - 5.5V supply and use the sensor with 3 pins.
•  Do not hold the soldering iron on a lead for a long time; when soldering close to the body the chip can be damaged by heat.

Package contents:

•  1 Piece DS18B20 TO-92 IC Digital Temperature Sensor
•  Note: 4.7k pull-up resistor, cable and control board are not included in the package.