ESP8266 Community Forum

- Sun Jul 19, 2015 4:51 pm #23668 Hi guys,

I'm trying to power my esp8266 with the LM2596 (set to 3.3v), and it's working great... Now i'd like to connect a PIR Sensor. Using the 3.3v power line (as showed in the picture below).



Now, this kind of connection seems not to be working.. I mean the esp8266 responds correctly, but the PIR sensor doesn't. Why? low power?

- Sun Jul 19, 2015 9:23 pm #23683 Looking at posts like this:

https://www.adafruit.com/products/189

A PIR may be a 5V device and won't work from a 3.3V source.

Free ESP8266 book available for download here.

- Sun Jul 19, 2015 10:48 pm #23686 Some work from 3.3 but if not then use an appropriate power source for it Your buck converter needs to feed the PIR 5V but the ESP8266 3.3V. The earths must all be joined and the sense wire would need to be dropped to 3.3V if you are feeding it to the ESP8266. Resistor divider or two diodes I would suggest. So basically the PIR at 5V senses movement sending the sense wire high which is fed to the ESP8266 digital pin.

Get you modules here:

https://www.banggood.com/custlink/KvGGhGF4wG

- Mon Jul 20, 2015 6:44 am #23703 I have the same(if it's from banggood,ebay,....)
With 3.3v the sensor hasn't enough power to work correctly, with 5v everything is fine,
use a LM7805 for a powersource over 5v or a cheap step up when you are using a powersource under 5v to get 5v for your sensor.

Joshua