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

you need to use a transistor and power goes to motor and sensor, negative from motor goes to the collector pin on transistor, output from sensor goes to the middle (base) of transistor, u then have a negative wire going to emitter pin on transisotor and another negative wire for sensor ( that negative wire would go to where ever you have the negative spot on your bread board.

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.

The sensor does exactly what it says. I opted to have it trigger on every movement (vs latched), and it works every time.However, mounting can be tough. There are no mounting holes, and the output pins are not long enough to plug directly into a PCB. I will likely plug it into a 3-pin socket and mount that to a PCB, and then mount the PCB itself to my project case.

Works as advertised.

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.

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 easySensor:Red wire to Vbus on PicoYellow wire to GP28 on PicoGray wire to GND on PicoOled:Gnd to GndVCC to 3V3(out)SCL to I2Cx SCLSDA to I2Cy SDALED:GP15 to resistor to LED to GndBuzzer:GP14 to buzzer to GndMicropython:import machineimport utimefrom ssd1306 import SSD1306_I2Csensor_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)

This PIR connected to a ESP32-CAM inside a 3d printed box with a single 16550 battery to power it. PIR senses motion, fires up the ESP32-CAM which snaps a picture, connects to WiFi and sends via text a picture of my mail being delivered. Low power draw and ideal for any PIR project

Try starting with the sensitivity adjustment dial turned completely counter-clockwise and the delay dial completely clockwise. I found it a lot easier to tweak and troubleshoot at these settings and fine tune at the end. Also change the jumper on the underside unless you want repeat trigger mode. The component itself is durable enough and effective at the right settings.