Infra red (infra red) is the diffraction wavelength elektromagnet more than its visible light is between 700 nm and 1 mm. Infra red rays of light is not visible. If viewed with the light spektroskop the infra red light radiation will be visible on the spectrum elektromagnet with wavelength on the wavelength red light. With this long wave infra red light so it will not appear by the heat radiation, but it still feels embossed / detected.
because the infra red is not visible by naked eye so the idea arose to create a tool pendeteksi movement using infra red this
in the image below is the following circuit diagram of an infrared motion detector that can be used to sense intrusions. Infra red rays reflected from a static object will be in one phase, and the rays reflected from a moving object will be in another phase.The circuit uses this principle to sense the motion.
NE 555 is wires as an astable multivibrator . IR diode connected at the output of this IC produces infrared beams of frequency 5Khz. These beams are picked by the photo transistor Q1 . At normal condition ie; when there is no intrusion the output pin (7) of IC2 will be low. When there is an intrusion the phase of the reflected waveforms has a difference in phase and this phase difference will be picked by the IC2. Now the pin 7 of the IC 2 goes high to indicate the intrusion. An LED or a buzzer can be connected at the output of the IC to indicate the intrusion.
- Comparators IC2a and IC2b are belonging to the same IC2 (LM1458).
- When there is disturbance in the air or vehicles passing nearby, the circuit may get false triggered.
- POT R5 can be used for sensitivity adjustment.