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Oscillation Values ESP+DHT11 Lua

PostPosted: Tue Sep 15, 2015 4:39 pm
by gordonpt
Hi every one,

I'm follow this tutorial:
http://www.labviewarduino.in/2015/05/ex ... speak.html

Everything work, but I have stupid values, specially in temperature, some time the temperatures falls 10ÂșC
I'm powering it with my FTDI cable, I thought that could be weak, but I've already put also my arduino powering it, with an extra 3,3v power source. and I've the same values.

I've also tried power the sensor with 5v (it says 3,5v to 5.5v) but without success.

see my values bellow, in the picture.

thanks in advance,
BR

Re: Oscillation Values ESP+DHT11 Lua

PostPosted: Wed Sep 16, 2015 3:59 am
by jankop
I had the same problem. This is probably the interference with WiFi from esp8266-01. I was unable to solve it. Finally, I bought a more expensive sensor HTU21. It is stable now.

Re: Oscillation Values ESP+DHT11 Lua

PostPosted: Wed Sep 16, 2015 9:09 am
by martinayotte
It could be that the power supply of the sensors is unstable due to surges of power requested by ESP.
Try adding a diode and capacitor to supply the sensors.

Re: Oscillation Values ESP+DHT11 Lua

PostPosted: Sat Sep 19, 2015 7:16 am
by seaspac
I have the same problem and using the same code, I wasted one complete day and thought my DHT11 sensors are bad, then I put my DHT11 sensor to and arduino uno to confirm, it works very good and stable with arduino, so the problem is in the code code or esp. I am using an ESP12E. I am also looking at checksum values which never match. I removed the things speak code and only seeing the code on serial monitor in ESPlorer, and there is no wifi activity to be sure to have no interference from radio. I am also using a seperate 3.3V power supply. I think the code is not robust. I have tried other code based on NodeMCU firmware repository in the modules there is dht library and example code. https://github.com/nodemcu/nodemcu-firm ... es/dht_lib this is also not working giving me very wrong readings humidity always 0% and some - number for temperature.

now I think I should create a new code from dht11 datasheet or use adafruit dht library to create code for lua.

any one has tried?