ESP8266 Community Forum

- Thu Jan 01, 2015 4:47 pm #6090 viewtopic.php?f=6&t=929
Here. I saw in source code.

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- Fri Jan 02, 2015 8:42 pm #6157 I'm beginning to wonder if this is possible at all using lua.

For the life of me I can't get the chip to correctly control the gpio pins. With the DHT22 connected it is always set as high, calling gpio.write(pin, gpio.LOW) does nothing .

If anyone else has any luck feel free to post it .

Regards

Cdr

- Sat Jan 03, 2015 1:04 am #6163

I'm beginning to wonder if this is possible at all using lua.

For the life of me I can't get the chip to correctly control the gpio pins. With the DHT22 connected it is always set as high, calling gpio.write(pin, gpio.LOW) does nothing .

If anyone else has any luck feel free to post it .

Regards

Cdr

Which version of ESP do you have? The very first ESP-01 did not have GPIO pins connected to the output pins of the board - therefore doing anything with the code would result in absolutely nothing.
And, also, please check the version of nodeMCU - the mapping of pins to GPIO changed twice and therefore output something to pin 8 might no longer work as it is now different I/O pin...
I would suggest to get the latest nodeMCU firmware, set the GPIO2 (pin 4) to low and high and connect, let's say, LED with 330 ohm resistor to check the functionality.

- Sat Jan 03, 2015 1:24 am #6164 When I take this from your code and put it on a ESP-07/12 module:

Code: Select allpin  = 4;
-- Initiliase bit data array
bitData = {}
gpio.mode(pin, gpio.OUTPUT)
gpio.write(pin, gpio.LOW)
tmr.delay(20000)
gpio.write(pin, 1)
gpio.mode(pin, gpio.INPUT)


I get this from a DHT11:

Zoom of reply section:

In the case of both DHT11/22 I see varying advice on the start pulse length. I went with 18ms+ based on some random data sheet. I have it on Pin 4 (GPIO2) with a 4.7k pullup. You have numerous cases of humidity spelling errors, so variables are not working correctly. Even after fixing that I can't get the checksum to work. At the beginning of your code during the start pulse, the Print functions were preventing the lines from changing levels. When removed I saw the proper pulsing of GPIO2. Can't explain that, just is my observation.

Edit: I want to point out that you have a good start with your code. I will continue messing with it as well as I'd like to see my DHT11's working.