Anonymous
Mar 26, 2026
Rating: 4/5
Solid performance
Does exactly what it says on the tin. The L/H trigger mode jumper is a nice feature for different application logic. Only wish the cables were included.
Description
Reviews
| Brand | - |
| Category | Robotics / STEM Teaching Tools / Sensors |
| Origin | - |
| Model Number | HC-SR501 |
| Operating Voltage | DC 4.5V - 20V |
| Detection Distance | Up to 7 meters |
| Detection Angle | < 100 degrees cone angle |
| Trigger Mode | L (Low) and H (High) selectable via jumper |
| Delay Time | Adjustable from 5 seconds to 300 seconds |
| Blockade Time | Fixed at 2.5 seconds (default) |
| PCB Dimensions | 32mm x 24mm |
| Sensor Type | Pyroelectric Infrared (PIR) |
| Output Signal | High level 3.3V / Low level 0V |
Anonymous
Mar 26, 2026
Rating: 4/5
Solid performance
Does exactly what it says on the tin. The L/H trigger mode jumper is a nice feature for different application logic. Only wish the cables were included.
Anonymous
Mar 20, 2026
Rating: 5/5
Great for simple alarms
Integrated this into a basic intruder alert system. The 7-meter range covers my living room perfectly. No false alarms so far after two weeks of testing.
Anonymous
Mar 17, 2026
Rating: 5/5
Excellent for learning electronics
Bought this for a university project. The documentation online is plentiful, and the module itself is robust. It detected motion instantly during our demo.
Anonymous
Mar 16, 2026
Rating: 5/5
Perfect for Arduino projects
This sensor works flawlessly with my Arduino Uno. The detection range is accurate, and the sensitivity adjustments are very responsive. Great value for money.
Anonymous
Mar 10, 2026
Rating: 5/5
Reliable and compact
Small form factor makes it easy to hide in enclosures. The voltage range is wide enough to run directly off a 9V battery or a 5V USB supply.
Anonymous
Mar 02, 2026
Rating: 4/5
Good sensitivity, needs calibration
Works well for my hallway light automation. Had to tweak the delay potentiometer a few times to get the timing just right, but once set, it's reliable.
Q: Does this module come with a lens cover?
A: Yes, it comes with a standard white Fresnel lens dome pre-installed. This lens focuses the infrared signals onto the sensor element.
Q: What is the difference between L and H trigger modes?
A: In H mode (repeatable trigger), the output stays high as long as motion is detected. In L mode (non-repeatable), the output goes high once and waits for the delay time to finish before sensing again.
Q: Can this sensor detect motion through glass?
A: No, PIR sensors cannot detect infrared radiation through glass as glass blocks IR waves. The sensor needs a direct line of sight or an open window.
Q: How do I adjust the detection distance?
A: There is a potentiometer labeled 'Distance' on the board. Turn it clockwise to increase sensitivity and range, or counter-clockwise to decrease it.
Q: Is it compatible with Raspberry Pi GPIO pins?
A: Yes, it is compatible. Since the output is 3.3V high, it can be connected directly to a Raspberry Pi GPIO input pin without needing a level shifter.