living with the lab IR Object Detection Infrared

living with the lab IR Object Detection Infrared (IR) light leaving an LED reflects off an object. The reflected light travels back to an IR receiver. The IR receiver “detects” the presence of the object. The object does not need to move to be detected. IR receiver IR lig ht re IR LED flect ed o ff ob ject IR light from LED

living with the lab The Parts Panasonic PNA 4602 M supply voltage: 4. 8 V – 5. 2 V current: 3 m. A This sensor detects infrared (IR) light. However, to avoid detecting the IR component of regular sunlight or light from other stray IR sources, the sensor only looks for light coming in at 38 k. Hz. IR LED (not your usual LED) outputs 940 nm wavelength light We write an Arduino sketch to make this LED flash 38, 000 times per second so it can be detected by the PNA 4602 M. 2

living with the lab IR Light IR detector is most sensitive around 950 nm or 0. 95(10)-6 m Panasonic documentation for PNA 4602 M wikipedia. org 3

living with the lab Install an LED Shield It is important to install the LED in an enclosure to properly direct the IR light. Your kit includes the black pieces shown. Insert the legs of the LED through the holes in the longer black cylinder, and then install the smaller top piece over the exposed end of the LED. If you don’t have a shield, a piece of paper can be rolled up and taped around the LED. Your LED will look like this after shielding. 4

living with the lab LED Circuit 220Ω IR Receiver Circuit 5 V from digital output pin on Arduino 220Ω to digital input pin on Arduino Be sure to aim your LED and IR detector so that they have a clear view (nothing in the way) 5

living with the lab Arduino Sketch void setup() { Serial. begin(9600); pin. Mode(2, OUTPUT); pin. Mode(3, INPUT); } void loop() { tone(2, 38000); int IR_status= digital. Read(3 ); Serial. println(IR_status); delay(100); } // allows output to display // define digital pin 2 as an output (output to LED) // define digital pin 3 as an input (input from sensor) // // output a LOW HIGH LOW sequence at 38, 000 Hz acquire the status of the IR sensor display the status of the IR sensor wait 100 ms between sensor queries nothing is detected by IR sensor something is detected by IR sensor 6