This project is based on AM612 smart infrared sensor design night light
With a 3.3-5V power supply, the LDO (HT7333) is used to voltage to 3.3V.
Onboard 6 patch LEDs, power is 0.5W
Infrared sensitivity is adjusted by variable resistor R4
Opening light delay time by variable resistor R6
Equipped with a Micro USB charging port, charge a power supply lithium battery
Spend a nightlight switch, work when switching opens
Photoactic resistor selection: 0.5m ohm, 5-10K ohm during the day, enabling the voltage dividing resistance of 100K, the OEN-terminal voltage is 0.1VDD during the day, Oen enables it, not working. Night Oen end voltage is 5/6 VDD, Oen enables effective, and the small lamp works.
Simulation 3D PCB Figure
AM612 Working Principle Introduction
Am612 has a total of 6 feet, except for VDD and VSS (GND), REL, OEN, SENSE, ONTIME
Rel: Output pin, after receiving the threshold induction in the infrared PIR, REL will output a high level of a period of time, and the duration is controlled by the ONTIME foot voltage.
OEN: Enable feet, the foot voltage is greater than 0.4VDD, which is enabled when it is less than 0.2VDD. This design is invalid. This design uses the light-sensitive division voltage VDD to control the enable effect of Oen, and it does not light the day. The effect of bright sparkles at night.
SENSE: Sensitive Sensitive Adjustment Feet, according to the potential size on Sense, change the sensitivity of the infrared sensing, the smaller the voltage, the higher the sensitivity, the farther the induction range (requires less than 0.5VDD)
OnTime: Delayed time adjustment pin, change the power of the REL output on the power of the REL output, the larger the voltage, the longer the delay, the delay is (2.3S-4796S), this design The night light delay time can be adjusted around 2.3S-40S.