Infrared sensor light-controlled night light based on AM612

• This project is a night light designed based on the AM612 intelligent infrared sensor.
• It can be powered by 3.3-5V, and use LDO (HT7333) to regulate the voltage to 3.3V for power supply.
• There are 6 SMD LEDs on the board with a power of 0.5W.
• Infrared sensing sensitivity is adjusted through adjustable resistor R4
• The light-on delay time is adjusted through the adjustable resistor R6
• Equipped with micro usb charging port, which can charge the lithium battery
• Comes with night light switch, works when the switch is turned on
• Photoresistor selection: 0.5M ohm at night, 5-10K ohm during the day, the enable voltage dividing resistor size is 100K, the maximum OEN terminal voltage during the day is 0.1VDD, the OEN enable is invalid and does not work. At night, the OEN terminal voltage is 5/6 VDD, the OEN enable is valid, and the small light works.

Introduction to the working principle of AM612:

• AM612 has 6 pins in total, except for VDD and VSS (GND), they are REL, OEN, SENSE, and ONTIME.
• REL: Output pin. After the infrared PIR receives the threshold sensing, REL will output a high level for a period of time, and the duration is controlled by the ONTIME pin voltage.
• OEN: Enable pin. When the pin voltage is greater than 0.4VDD, the enable is valid. When the pin voltage is lower than 0.2VDD, the enable is invalid. In this design, a photoresistor is used to divide VDD to automatically control the enable effect of OEN, so that the light does not turn on during the day. Bright sparkling effect at night.
• SENSE: Sensing sensitivity adjustment pin, which changes the sensitivity of the infrared sensing according to the potential on SENSE. The smaller the voltage, the higher the sensitivity and the farther the sensing range (needs to be less than 0.5VDD)
• ONTIME: Delay time adjustment pin, changes the delay time of REL output high level according to the potential on ONTIME. The greater the voltage, the longer the delay. The delay range is (2.3s-4796s). In this design The night light delay time can be adjusted from about 2.3S to 40S.

In the schematic design, each pin uses a resistor voltage divider method to change the pin voltage for control, and at the same time, a small capacitor is connected in parallel for filtering and voltage stabilization.

The project has been shared to the Lichuang community, the link is http://club.szlcsc.com/article/details_44206_1.html Electronics enthusiast website: http://bbs.elecfans.com/jishu_1923055_1_1.html (The two links are because of electronics Third-party forums such as enthusiasts will eat up external links and cannot achieve the effect of mutual links 23333)