HC-SR501 ( motion sensor )on nodeMCU, is my sensor broken ?

Posted on Sat 9th, September 2017

• #1

Antoine
Hi everyone, I'm trying to read a HC-SR501 with my nodeMCU but I struggle a bit :(

Wiring :

VCC to vin (5V)
OUT to A0
GDN to GDN

I tried :
```
setWatch(function() {
  console.log("Movement detected");
}, NodeMCU.A0, {repeat:true, edge:"rising"});
```
Never got any detection

I tried
```
setInterval( () =>{

   console.log( analogRead(NodeMCU.A0) );
  // print 0.00097751710 all the time

},1000);
```
I swapped the sensor for a water level sensor and console.log( analogRead(NodeMCU.A0) ); and the water level is detected normally.

Did I miss something ?

Thank you a lot for your help :)
• #2

MaBe

HC-SR501 datasheet describes output as "TTL output: 3.3V, 0V" so try a D pin like NodeMCU.D1
• #3

Antoine

Hi MaBe,

Thanks for the heads-up :)

I'm gonna try this.
• #4

Antoine
Issue resolved :)

I tried a digital pin without any success :(

I tried an other HC-SR501 and it worked. So my sensor was definitely broken.

here the code that's working :
```
setWatch(function() {
  console.log("Movement detected at : ", Math.floor(Date.now() / 1000) );
}, NodeMCU.D6, {repeat:true, edge:"rising"});
```

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