PIR Motion Sensor HC-SR501
by Generic
SKU: PSA-CMP-PIR
No reviews yetTypical India street price
₹45–₹90
Detects moving humans via infrared body heat.
Interface: Digital
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Concept
Passive InfraRed: it senses change in IR, not a camera image.
A little theory
Pyroelectric element + Fresnel lens. Dual elements cancel slow ambient change; motion unbalances them. In the classroom, treat PIR Motion Sensor HC-SR501 as a beginner part using Digital. Typical India street price is about ₹45–₹90. Always verify voltage and pin labels on your exact module — silk screens vary across clones. Start with a datasheet or trusted learn guide, power the part correctly, share GND with the MCU, and test with a simple blink/read sketch before building the full project. Measure voltages with a multimeter when something fails, and keep actuator current off the MCU regulator.
How it works in a project
OUT goes HIGH for a few seconds after motion. Two pots: sensitivity and time. Jumper repeat/single trigger.
Classroom & project use
- Room occupancy
- Security lamp
- Welcome bot
Buying in India
Precautions
- Let it settle 30–60 s after power-up
- Pets and heaters can false-trigger
Specifications
| Range | 3–7 m |
| Angle | ~110° |
| Output | Digital HIGH on motion |
| Category | Sensors |
| Difficulty | Beginner |
| Voltage | 5–20V (module often 5V) |
| Interface | Digital |
Pinout
See module silkscreen: typically VCC, GND, and signal pins. Confirm labels against the seller photo — clones vary.
