Project 2
Temperature Monitor(Beginner to Intermediate Level)
About:
In this article, we will be interfacing TMP36 Temperature Sensor with Arduino. TMP36 is a precision centigrade temperature sensor that can precisely calculate the surrounding temperature. Connecting it with Arduino Uno can display the temperature getting from the sensor.
Components Required:
TMP36 Temperature Sensor
Arduino Uno
Breadboard
Jumper wires
Circuit Diagram
The red wire is connected from 5V power from Arduino to TMP36’s power(Vs+).
The black wire is connected from TMP36’s Vout to Arduino’s A0(Analog) pin.
Green wire is connected from the ground(GND) of Arduino to the ground of the TMP36 sensor.
The yellow wire is connected from the 3.3V of Arduino to the reference voltage(AREF) pin in Arduino. It is used to improve the accuracy of the TMP36 sensor.
Working Principle
The TMP36 measures temperature using a solid-state approach. It takes advantage of the fact that the voltage drop between the base and emitter (forward voltage – Vbe) of a diode-connected transistor falls at a predictable pace as the temperature rises. It is simple to construct an analog signal that is directly proportional to temperature by properly magnifying this voltage change.
Calculating the output voltage from the Analog temperature data
We used the inbuilt analogRead() function to read the data from the A0 pin. After reading we then calculate Vout using the formula given below:
Vout = (reading from A0 pin) * (3.3 / 1024)
For Example: If the reading from the A0 pin is 248V then Vout will be ~800mV or ~0.8V.
How to measure temperature
Simply connect the left pin to power (5V) and the right pin to the ground to use the TMP36. The analog voltage on the middle pin will thereafter be directly proportional (linear) to the temperature in °C.
Simply apply the following formula to convert voltage to temperature:
Temperature (°C) = (Vout – 0.5) * 100
For Example: If the output voltage is 0.8V then the temperature will be approx. to 30°C.
