XINGYHENG 5Pcs HC-SR505 Micro Body Sensing Module PIR Motion Detector Switch Module High Power High Efficiency Digital Measurement for Electronic Practice DIY

Received today and did tests. Be careful if you have short times to consider. When first powered up there is a lengthy(what I would call warm up) time for it to settle down. I did ty testing with a stable lab power supply of 5VDC. After it settled down the signal lead was in LOW condition. when I moved my hand in front of senior it quickly went high. Now the problem for some people.... the output remains HIGH for aprox 10 seconds. That would be ok for some things. Like most items on Amazon there is very little information. You need reviews or already know the item. If counting people or like items it is way to slow for accurate counting. Easily 10 people could go by in 10 seconds counting as one. One second would be better. For sensing the existence of some one present with no need for counting it works ok. Just wanting another buyer to know some info about it. It was indicated there was 25 reviews but only about 4 showed up in the list. We'll see if mine does. It is a nice size to add to my projects.

A good little unit. I use it for detecting the presence of people. I find that a PIR loses track of a stationary person...so I pair it with an Ultrasonic sensor. The resulting combination senses human presence well (for me) and turns my automaton on and off reliably.

Used to set alarm on stairs when kid gets close they work great pretty well built also

Good product!

I found that several of this batch of sensors are not functioning correctly. They tend to send a High even when the sensor is covered up. They were cheap but it might be worth paying more and sourcing from one of the famous component suppliers.

Petit et de faible consommation. Mais ces modules ne détectent qu'à moins d'un mètre. 60 cm au plus. Je suis un peu déçu. La sortie est à 3.8 volts peu importe la tension d'entrée assez pour une détection TTL.À vrai dire, ces trucs ne servent pratiquement à rien.heureusement, ça n'a pas couté une fortune.

Didn't work properly.

Fonctionne bien!