Miniature PIR sensors comparison
The old good HC-SR501 is just huge. It works well, and it has all "tuning" options. However, its size matters! :-)
Testbed:
Sensors are tested with ESP8266. The received digital data is sent to MQTT broker, and analyzed offline.
All sensors are powered 3.3V from the same LDO power circuit as the ESP8266.
All sensors are faced the same direction at single location. Test duration is 2 days.
Code name
HC-SR505
DWM PM-8
BR313
KeyesStudio PIR
Picture
PIR Sensor
SLA-P
???
AS312
AS312
Test result
Tested 5 sensors of this type. 3 of them stay at high all times. 1 of 2 remaining sensors triggered back and forth like mad. One sensor worked more or less stable, however was not sensitive enough. It reacted to fast and close movement only. People experiencing problems with this sensor: Report1, Report2, Report3.
It is very cheap, easy available, and not recommended.
2 sensors tested. They were very sensitive for movement, however, triggered about twice a minute when no movement. Not recommended although it has very nice feature set.
Has very simple circuit and smallest components count. Smallest size among sensors. Works solid with no tuning. Highly recommended.
Has very simple circuit and smallest components count. Reports motion when no movement once in few minutes sets high for 10-30 seconds. Then works OK. Expensive for tested range and for diluted feature set. Recommended.
Notes
Can be reduced in size by removal LDO+related circuitry. Timer can be adjusted (in theory, not trivial). Has placeholder for amplifier-transistor.
Requires resistor 20k on signal pin. Has adjustable timer and LDR-ready.
No timer, no re-trigger, no LDR ready.
No timer, no re-trigger, no LDR ready.
Hint: The Fresnel lens (white cap) of AS312 sensors is quite wide. The lens of SR505 sensor is smaller. AS312 tested with small lens of SR505 shows even better sensitivity with no adding noise or instability.
Datasheet of AS312/AM312 sensor in English (original version is in Chinese).
PIR sensors are good for standalone devices or for devices with very limited power supply. They consume usually microamperes for work.
For devices where there is no problem with power supply, the microwave motion detectors are recommended (FC1816 for instance is one of the smallest and the properly working). They consume tens of milliamperes and "see through walls".
Testbed:
Sensors are tested with ESP8266. The received digital data is sent to MQTT broker, and analyzed offline.
All sensors are powered 3.3V from the same LDO power circuit as the ESP8266.
All sensors are faced the same direction at single location. Test duration is 2 days.
Code name
HC-SR505
DWM PM-8
BR313
KeyesStudio PIR
Picture
PIR Sensor
SLA-P
???
AS312
AS312
Test result
Tested 5 sensors of this type. 3 of them stay at high all times. 1 of 2 remaining sensors triggered back and forth like mad. One sensor worked more or less stable, however was not sensitive enough. It reacted to fast and close movement only. People experiencing problems with this sensor: Report1, Report2, Report3.
It is very cheap, easy available, and not recommended.
2 sensors tested. They were very sensitive for movement, however, triggered about twice a minute when no movement. Not recommended although it has very nice feature set.
Has very simple circuit and smallest components count. Smallest size among sensors. Works solid with no tuning. Highly recommended.
Has very simple circuit and smallest components count. Reports motion when no movement once in few minutes sets high for 10-30 seconds. Then works OK. Expensive for tested range and for diluted feature set. Recommended.
Notes
Can be reduced in size by removal LDO+related circuitry. Timer can be adjusted (in theory, not trivial). Has placeholder for amplifier-transistor.
Requires resistor 20k on signal pin. Has adjustable timer and LDR-ready.
No timer, no re-trigger, no LDR ready.
No timer, no re-trigger, no LDR ready.
Hint: The Fresnel lens (white cap) of AS312 sensors is quite wide. The lens of SR505 sensor is smaller. AS312 tested with small lens of SR505 shows even better sensitivity with no adding noise or instability.
Datasheet of AS312/AM312 sensor in English (original version is in Chinese).
PIR sensors are good for standalone devices or for devices with very limited power supply. They consume usually microamperes for work.
For devices where there is no problem with power supply, the microwave motion detectors are recommended (FC1816 for instance is one of the smallest and the properly working). They consume tens of milliamperes and "see through walls".