HiLetgo 3pcs HC-SR501 PIR Infrared Sensor Human Body Infrared Motion Module for Arduino Raspberry Pi

Function: My order included 3 units. Each of these worked. The device has controls for adjusting duration triggered and sensitivity (detection distance). Once triggered the duration ranged 1sec to 6min. These values are consistent w/ the datasheet. I did not test sensitivity. Electrical Characteristics: Sensor pin output (Vout) range 3.19-3.33v across the input range tested (4-7v, datasheet recommended VCC range: 5-20v). PCB is approx. 24mm by 32mm (15/16inch x 1 1/4inch). Solder joints are clean. Would buy again.

Nifty little motion sensor. Easy to code and use with Arduino or Pico 2W. Nice feature is the ability to adjust time delay and sensitivity.

Once you can figure out how these are supposed to work, they do the job well. There are differing opinions (documentation) on how long the delay time is supposed to run; I read anywhere from 30 mins to 3 mins (mine have measured about 2.5 to 3 mins). The sensitivity doesn't seem to change much. The trigger once / repeat trigger jumper is a nice feature, and makes it possible act as either a digital switch, or an on as long as an infra-red delta is detected. If the input voltage drops to about 4.7v, the sensor misbehaves, and makes it appear as if other parts are failing, because the data output line switches on and off erratically; however, what can you expect with incorrect input voltage.

Inexpensive and versatile, this PIR sensor can be used to switch small, low power circuits or could be used to trigger a MOSFET for higher current applications as well. There are so many uses. I found the adjustments to be easy to make and stable once made. In my case, we used it to switch an LED strip for under bed lighting. When your feet hit the floor the LEDs come on as a night light to see where you are stepping without tripping over something. The sensitivity can be set so that the lights don't come on as you sleep. It's great!

These have been working without issue for my DIY ESPhome Home Assistant projects. I've ordered them 3 times now.

Two of them functioned fine. The third did not work at all. For the price, it wasn't worth going through a return, so maybe buy one extra. Making fun small projects gets expensive in time and gas if you have to do a lot of returns.

At first I thought these were defective, but I found that when using it with a Raspberry Pi 4, it requires an extra diode before the V-in pins, otherwise some voltage instabilities from the Pi will cause false triggers very regularly on 60-second cycles (actually 59.75 seconds if you measure it out for a long enough time). After a lot of testing, including using it to drive an LED (no output to the pi itself), I was almost ready to give this a bad review, before I found some suggestions online for other HC-SR501 sensors regarding their behavior under power instabilities. I do not believe this issue was due to outside EM interference, as I tried it at multiple locations. Other than that, happy with the product and price.

I had fun making a little circuit that beeps, flashes an led and writes to an oled display when anything in the room moves. It came with a nice data sheet, making the wiring easy Sensor: Red wire to Vbus on Pico Yellow wire to GP28 on Pico Gray wire to GND on Pico Oled: Gnd to Gnd VCC to 3V3(out) SCL to I2Cx SCL SDA to I2Cy SDA LED: GP15 to resistor to LED to Gnd Buzzer: GP14 to buzzer to Gnd Micropython: import machine import utime from ssd1306 import SSD1306_I2C sensor_pir = machine.Pin(28, machine.Pin.IN, machine.Pin.PULL_DOWN) sda=machine.Pin(20) scl=machine.Pin(21) i2c=machine.I2C(0, sda=sda, scl=scl, freq=400000) led = machine.Pin(3, machine.Pin.OUT) oled = SSD1306_I2C(128, 32, i2c) buzzer = machine.Pin(14, machine.Pin.OUT) def pir_handler(pin): utime.sleep_ms(100) if pin.value(): print(i2c.scan()) oled.text('Motion detected!!!', 0, 0) oled.show() utime.sleep_ms(1000) for i in range(20): led.toggle() buzzer.toggle() utime.sleep_ms(100) utime.sleep_ms(100) oled.fill(0) oled.show() sensor_pir.irq(trigger=machine.Pin.IRQ_RISING, handler=pir_handler)

Works as good as it says.

working good with arduino.

I ordered for my kid for experimenting with Arduino, he says they work great

the product didn't come with a jumper set and there were no pins for the H and L although they were in the photo!

No repeated trigger connection and no LDR SLOT.