# DHT22 AM2302 sensor doesn't work in nodered
**URL:** https://discourse.nodered.org/t/dht22-am2302-sensor-doesnt-work-in-nodered/27513
**Category:** General
**Created:** [29 May 2020 21:04 UTC](https://discourse.nodered.org/t/dht22-am2302-sensor-doesnt-work-in-nodered/27513 "2020-05-29T21:04:06Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@Mario-1977](https://discourse.nodered.org/u/Mario-1977)
#### Post date: [29 May 2020 21:04 UTC](https://discourse.nodered.org/t/dht22-am2302-sensor-doesnt-work-in-nodered/27513/1 "2020-05-29T21:04:06Z")
Platform: pi 3 model B+ rev.1.3
OS: Rasbian
Node-RED: 1.0.5
Node.js: v12.17.0
problem node: node-red-contrib-dht-sensor v1.0.4
bcm2385 revision. a020d3
DHT22 sensor: AM2302
Hello I'm new in using Nodered but I found it perfect for my home automation project.
I bought 2 sensors DHT22 instead of the DHT11.
I used succesfully the DHT11 sensor connected to GPIO23 (physical pin 16) recieveing temperature and humidity values.
I changed the DHT11 with the DHT22 sensor connected to the same GPIO23 and changing the sensor model into the node-red-contrib to DHT22
and I recived wrong values as output:
{"\_msgid":"99d420d7.3025b","topic":"rpi-dht22","payload":"0.00","humidity":"0.00","isValid":false,"errors":4,"location":"Test\_T&H","sensorid":"dht22"}
I tried the same sensor with the same connection with Adafruit library and it works properly
I don't know how to solve it. But for me it's necessary to find a solution because I want to continue to work with nodered.
Can someone help me?
Thank you
Regards
---
### Author:  [@gerry](https://discourse.nodered.org/u/gerry)
#### Post date: [29 May 2020 22:17 UTC](https://discourse.nodered.org/t/dht22-am2302-sensor-doesnt-work-in-nodered/27513/2 "2020-05-29T22:17:24Z")
I had the same thing happen when I switched from a dht11 to dht22. What finally fixed mine was changing the pin numbering from physical pins to bcm. Sounds dumb but it worked.
---
### Author:  [@Mario-1977](https://discourse.nodered.org/u/Mario-1977)
#### Post date: [31 May 2020 10:24 UTC](https://discourse.nodered.org/t/dht22-am2302-sensor-doesnt-work-in-nodered/27513/3 "2020-05-31T10:24:37Z")
> [@gerry](#):
>
> Sounds dumb but it worked.
Thanks gerry for your suggestion but in my case it doesn't work. I changed from Physical pins (rev.2) to
BCM gpio
following my wiring connection
but I always received wrong values:
{"\_msgid":"e68c589b.d4d8f8","topic":"rpi-dht22\_test","payload":"0.00","humidity":"0.00","isValid":false,"errors":4,"location":"Test\_T&H","sensorid":"dht22"}
I tried also to change the connection pin to other pins but nothing happened.
I thought the possible problem could be the correlation between the pins in the list node-red-contrib-dht-sensor and the real pins so I changed (and tested) all the proposed pin numbers into the node-red-contrib-dht-sensor list, but nothing.
Following my wiring pin table:
Could the problem be a no compatibility of the sensor DHT22 AM2302 with the node-red-contrib-dht-sensor? Or does it depend from my hardware configuration?
Does anyone know if there is an alternative palette to node-red-contrib-dht-sensor to control a DHT22 sensor into nodered?
---
### Author:  [@zenofmud](https://discourse.nodered.org/u/zenofmud)
#### Post date: [31 May 2020 10:53 UTC](https://discourse.nodered.org/t/dht22-am2302-sensor-doesnt-work-in-nodered/27513/4 "2020-05-31T10:53:35Z")
Just to verify, did you install the BCM2835 library and node-dht-sensor as it says in the [pre-req's](https://flows.nodered.org/node/node-red-contrib-dht-sensor)?
---
### Author:  [@Mario-1977](https://discourse.nodered.org/u/Mario-1977)
#### Post date: [31 May 2020 12:34 UTC](https://discourse.nodered.org/t/dht22-am2302-sensor-doesnt-work-in-nodered/27513/5 "2020-05-31T12:34:34Z")
No I didn't install the BMC libraries as told in the pre-req's.
But I just do it and update the BMC to the version 1.65:
Then I followed the other 2 steps in pre-req's and I re-installed the node-dht-sensor dependency and the node-red-contrib-dht-sensor node.
And I updated npm to the latest version (patch) 6.14.5 and Node-js to version 12.17.0
The output values coming from node-red-contrib-dht-sensor are still wrong with both BCM GPIO (in my case 23) or Physical pin rev.2 (in my case 16).
---
### Author:  [@zenofmud](https://discourse.nodered.org/u/zenofmud)
#### Post date: [31 May 2020 15:05 UTC](https://discourse.nodered.org/t/dht22-am2302-sensor-doesnt-work-in-nodered/27513/6 "2020-05-31T15:05:43Z")
Are you sure you have the pins connected properly? Is it possible the dht22 pin outs on the board are different than the dht11?
---
### Author:  [@zenofmud](https://discourse.nodered.org/u/zenofmud)
#### Post date: [31 May 2020 15:34 UTC](https://discourse.nodered.org/t/dht22-am2302-sensor-doesnt-work-in-nodered/27513/7 "2020-05-31T15:34:25Z")
After installing the BMC v1.65 library, node-dth-sensor and then the node-red-contrib-dht-sensor, I wired up a dht22 using:
Pin 1 (3.3v) to pin 1 of the dht22
Pin 6 (Gnd) to pin 4 of the dht22
Pin 16 (BCM 23) to pin 2 of the dht22
and a 10K resistor between pins 1 and 2 of the dht22
the node is reporting fine.
```auto
{"_msgid":"591e2642.bdc308",
"topic":"rpi-dht22",
"payload":"23.20",
"humidity":"34.60",
"isValid":true,"errors":1,
"sensorid":"dht22"}
```
I would uninstall/install node-red-contrib-dht-sensor and try again. If that doesn't work, try another dht22.
---
### Author:  [@gerry](https://discourse.nodered.org/u/gerry)
#### Post date: [31 May 2020 15:56 UTC](https://discourse.nodered.org/t/dht22-am2302-sensor-doesnt-work-in-nodered/27513/8 "2020-05-31T15:56:00Z")
Just a note: Be careful with the resistor as many of the packaged DHT sensors have the resistor already in the circuit. I don't know if the DHT you are using has one or not but read the data sheet carefully.
---
### Author:  [@Mario-1977](https://discourse.nodered.org/u/Mario-1977)
#### Post date: [19 June 2020 17:27 UTC](https://discourse.nodered.org/t/dht22-am2302-sensor-doesnt-work-in-nodered/27513/9 "2020-06-19T17:27:52Z")
Hello I bought and tested a new sensor DHT22 (a branded one) and now it works fine. So my problem was the sensor.
I suggest to buy brended sensors and not generic unbrended sensors and of course to use the good node-red-contrib-dht-sensor.
Thanks to **gerry** and **zenofmud** for your suggestions
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [3 July 2020 17:27 UTC](https://discourse.nodered.org/t/dht22-am2302-sensor-doesnt-work-in-nodered/27513/10 "2020-07-03T17:27:53Z")
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