9. Input devices¶
Group Assignment¶
1. Infrared Speed Sensor¶
The Infrared Speed Sensor Module is an IR counter that has an IR transmitter and receiver. If any obstacle is placed between these sensors, a signal is sent to the microcontroller. The module can be used in association with a microcontroller for motor speed detection, pulse count, position limit, etc.
How it works
When operating, the infrared light-emitting diode continuously emits infrared light (invisible light), and the phototransistor will conduct if it receives it.
We connected the sensor to the Arduino and plotted the output. When there’s no object between the photodiode and phototransistor, the output is zero, and if there’s an object, the output is one.
Arduino Code
#define Sensor A1
void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
pinMode(Sensor,INPUT);
}
void loop() {
// put your main code here, to run repeatedly:
int SensorRead = digitalRead (Sensor);
Serial.println (SensorRead);
delay(100);
}
2. Thermistor Thermal Temperature Sensor¶
The Thermistor Temperature Sensor consists of an NTC (Negative Temperature Coefficient) thermistor, which measures temperature variations. This module provides both digital and analog outputs. An NTC thermistor is a variable resistor whose resistance decreases as temperature increases. The sensor’s sensitivity can be adjusted using the onboard potentiometer.
Arduino Code
#define Sensor A1
void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
pinMode(Sensor,INPUT);
}
void loop() {
// put your main code here, to run repeatedly:
int SensorRead = analogRead (Sensor);
Serial.println (SensorRead);
delay(100);
}
3. Rotary Encoder¶
A Rotary Encoder is a position sensor used to determine the angular position of a rotating shaft. It generates an electrical signal—either analog or digital—based on rotational movement.
How It Works When the disk rotates step by step, pins A and B make contact with the common pin, generating two square wave output signals.
Any of the two outputs can be used to determine the rotational position by counting pulses. However, to determine the direction of rotation, both signals must be considered simultaneously. By counting each step where the signal transitions from High to Low or Low to High, we can determine whether the signals have opposite values and thus identify the rotation direction.
Arduino Code
#define Sensor 3
void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
pinMode(Sensor,INPUT);
}
void loop() {
// put your main code here, to run repeatedly:
int SensorRead = digitalRead (Sensor);
Serial.println (SensorRead);
delay(100);
}
