The Temp Sensor for Arduino is the first project of a joint Modern Device-Liquidware collaboration. It’s capable of turning the Arduino into an instant thermometer, plugging directly into Arduino Duemilanove Analog Pins 2-5.

The TMP421 chip is a 12 bit I2C chip that works from minus – 40 to 125 degrees C, so the sensor is able to resolve .04 degrees C per bit. The absolute accuracy is guaranteed to be +/- 1 degree C. The relative resolution should make the sensor useful for a range of higher resolution activities such as sniffing out drafts around windows.

The Temp Sensor comes with a 4-pin male header (unsoldered) and 8 total pin-outs to allow for maximal flexibility in project use. With a small, narrow form factor, it’s easy to set up multiple Temp Sensors for local temperature monitoring as well.

A ready-to-go Arduino library is also available free for download at the Liquidware App Store for full, off-the-shelf integration with any Arduino project.

The chip communicates via I2C and also has an onboard remote temperature sensing capability as well.

Specifications

• TMP421 chip
• 4-pin male header included (unsoldered)
• Communicates over I2C protocol
• 1 Bi-directional data pin
• 1 Clock pin
• Ranges from – 40C to +125C with +/ – 1C accuracy
• Optional remote temperature probe input
• I2C Digital Interface
• Arduino Pin Compatible
• +5V Tolerant I/O

Arduino Pin Mapping

Analog 2 = Ground Analog 3 = Vin Analog 4 = Data Analog 5 = Clock

Resources

• TI TMP421 Datasheet
• Arduino Temp Sensor library and example code
• Up and running on the TempSensor in less than 5 minutes

Media

Link to the cheatsheet as a PDF...

Source Code 

#include "Wire.h"

#include <LibTemperature.h>

LibTemperature temp =

LibTemperature(0);

void setup() {

Serial.begin(9600);

}

void loop() {

Serial.print("Temp: ");

Serial.print(temp.GetTemperature())

;

Serial.println(" degC");

delay(100);

}