Anonymous
Mar 24, 2026
Rating: 5/5
Perfect for Arduino Projects
This sensor works flawlessly with my Arduino Uno. The detection range is accurate, and the adjustment pots for time and sensitivity are very responsive. Great value for hobbyists.
Description
Reviews
| Brand | - |
| Category | Robotics / STEM Teaching Tools / Sensors |
| Origin | - |
| Operating Voltage | DC 4.5V - 20V |
| Detection Distance | Up to 7 meters |
| Detection Angle | < 120 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 |
| Lens Type | Fresnel Lens included |
| Output Signal | 3.3V TTL High / Low level |
| Working Temperature | -15°C to +70°C |
Anonymous
Mar 24, 2026
Rating: 5/5
Perfect for Arduino Projects
This sensor works flawlessly with my Arduino Uno. The detection range is accurate, and the adjustment pots for time and sensitivity are very responsive. Great value for hobbyists.
Anonymous
Mar 10, 2026
Rating: 5/5
Reliable and cheap
We bought ten of these for our makerspace kits. They have held up well under constant student use. The voltage range is flexible enough for both 5V and 12V systems.
Anonymous
Mar 09, 2026
Rating: 5/5
Excellent for learning electronics
Bought this for a university project on smart lighting. The documentation online is plentiful, and the module itself is robust. The L/H trigger jumper is a nice feature for different use cases.
Anonymous
Mar 09, 2026
Rating: 4/5
Works as described
Solid little sensor. The delay time adjustment is quite wide, which is helpful. Only giving 4 stars because the pins were slightly bent upon arrival, but easy to fix.
Anonymous
Mar 02, 2026
Rating: 5/5
Great for intrusion alarms
Integrated this into a custom Raspberry Pi security system. The output signal is clean and easy to read. Detection angle covers my entire doorway perfectly.
Anonymous
Mar 01, 2026
Rating: 4/5
Good sensitivity, needs calibration
The module detects motion well, but I had to spend some time tweaking the sensitivity knob to avoid false triggers from my ceiling fan. Once calibrated, it works great for my hallway light project.
Q: What is the difference between L and H trigger modes?
A: In 'H' mode, the output stays high as long as motion is detected and resets after the delay once motion stops. In 'L' mode, the output goes high upon detection and remains high for the set delay time regardless of continued motion.
Q: Is the output compatible with 5V microcontrollers like Arduino?
A: Yes, the output is 3.3V TTL, which is recognized as a HIGH signal by most 5V microcontrollers including Arduino, ESP8266, and ESP32.
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. Test adjustments in small increments.
Q: Does this module work outdoors?
A: While the electronics function outdoors, the module is not weatherproof. You must house it in a waterproof enclosure if used outside, and ensure the lens is protected from rain and direct sunlight.
Q: Can this sensor be powered directly by a 9V battery?
A: Yes, the HC-SR501 operates on a DC voltage range of 4.5V to 20V, so a standard 9V battery is perfectly suitable.