HT7610A PIR Sensor



Its PIR sensor detects infrared power variations induced by the motion of a human body and transforms it to a voltage variation. If the PIR output voltage variation conforms to the criteria (refer to the functional description), the lamp is turned on with an adjustable duration. The circuit doesn?t required step down transformer and can work directly by applying 110V AC or 220V AC (Capacitor C7 needs to change for 220V AC (0.33uF/275V) and 110V AC (0.68uF/275V)Project is based on Holtek?s IC HT7610A, which is a CMOS LSI chip designed for use in automatic PIR lamp, flash or buzzer control. It can operate in 3-wire configuration for relay applications.  In our project we have used relay instead of Traic to connect any kind of load in output, HT7610B IC is suitable for traic and HT7610A for Relay application. The chip is equipped with operational amplifiers, a comparator, timer, a zero crossing detector, control circuit, a voltage regulator, a system oscillator, and an output timing oscillator.


– Supply Input 110V or 220V AC ( Capacitor Value needs to Change)
– No Step Down transformer required
– IC Operating voltage: 5V~12V
– Load Current 80mA when relay is on.
– Standby current of the IC: 100uA
– On-chip regulator
– Adjustable output duration
– 40 second warm-up
– ON/AUTO/OFF selectable by MODE pin
– Override function
– Auto-reset if the ZC signal disappears over 3 seconds
– On Board Relay to connect output Buzzer or Flash
– On Board LDR to Detect Day/Night operation
– J1 to Set the Mode
– PR1 to set the Sensitivity of the sensor
– PR2 to set the output Turn On Duration
– CDS R11 for Auto Day/Night detection
– (HIGH Voltage On Board) Do Not touch the PCB while power is on

This project offers three operating modes (ON, AUTO, OFF) which can be set through the MODE pin.

Source: Electronics Lab

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