I am trying to make a AC Dimmer control

Hello !

I am trying to make a AC Dimmer control just like in this link provided. While doing so i faced few issues and came up with few ideas, but i am having the following doubts before that.

  1. Can i use ESP8266 12-E because it has more GPIO’s available.
  2. Instead of Arduino pro micro can i use arduino uno ? (i will be using only the chip later standalone).
  3. What should be flashed to the ESP module before continuing any further ? Any particular firmware ?
  4. Not Blynk related… I was never able to send AT command from Serial monitor. And even i dont get the BLYNK connected on the serial monitor… What is the issue ? i tried with all the latest and few beta as well as older version of Arduino IDE but no luck.


In the project you’re referring to, the ESP-01 is simply used as a Wi-Fi modem. None of the ESP-01’s GPIO pins are available for use in the project, the only pins that are used are Rx and Tx.

I’m not familiar with the differences between the Pro Micro and the Uno, but the code seems to be using two serial interfaces without the use of softwareserial, which I don’t think is possible with an Uno.

Probably the latest AT firmware.

I think you need to expand on this quite a bit before anyone can provide a sensible answer.


i am talking about the wifi module that sits on the nodemcu.

The UNO too uses software serial to communicate on pin 3 and 2.
but will it work ? I tried this and couldnt get the device online.

Yes, i already did that using a software “ESP8266Flasher” Also called NODEMCU FIRMWARE PROGRAMMER. “https://github.com/nodemcu/nodemcu-flasher” . This is the link where i found the flasher… And flashed the NODEMCU. Does this flash the latest firmware available or should i provide any file to it ?

Ex. When the nodemcu connects to the wifi and comes alive and when we open the the serial monitor in the IDE it should show BLYNK connected , version, IP address, ping ms…, connecting to 192.xxx.x…x.
But in my case i am not getting any output on the serial monitor. But the nodemcu connects to the wifi and works fine. I checked with the baud rate as well. And just like this i cannot send AT commands to check the firmware version. When i type in AT or AT+GMR and hit send,i get nothing but a black serial monitor.
I know this is not a Blynk related problem. But i hope i can get some solution here.

Yes, I’m aware of that. You asked if you can use an ESP8266 12E because it has more GPIOs. Yes, you can, but those extra GPIO pins will be of no use to you, because you’re using the device as a Wi-Fi modem to allow your Arduino, which has no internet connectivity, to become internet enabled. You aren’t utilising any of the GPIO pins, except Rx and Tx, with any of these devices when they are used as a modem.

If you read my comment properly, you’ll see that I was saying that the sketch you link to DINDN’T use SoftwareSerial, but that it would probably be needed if you used an Uno, so the code would need to be adapted.

What baud rate are you using for that?
The default for most NodeMCU boards is 74890 or 115200.

Personally, I’d forget the Arduino altogether and use the NodeMCU as your processor. You may need to do some level shifting with the rest of the circuit - either using a voltage divider or a level shifting board, and change the PWM values from 0-254 to 0-1023.

All of this assumes that you’re comfortable/knowledgeable when working with mains voltages of course. If you aren’t then this project isn’t for you.


Ho yeah !! My bad i did even think about that. No use of the extra GPIO’s …

YESS YESS i said i am trying something like that. Not exactly that. Because hardware to Hardware things changes a bit…

Tried with starting from 9600 to 115200 and on 74890 it gives an error saying something like cause boot (2,3 ) i dont exactly remember what it was. But the nodemcu connects to the project and runs just fine.

Thanks for the concern… I have had did this long back with uno but obviously with out wifi and Blynk. so now thought of integrating.

SO can i use the ESP 12E ?? i want to use this due its SMD package. To test my soldering skills :stuck_out_tongue_winking_eye:

I did try that. But as soon as i connect the zero crossing pin to the nodemcu it doesnt react to the inputs from the rotary encoder for adjusting the brightness values. But when i rotate the encoder at very slow movement like one step for one sec it works just fine. But when i try to turn the encoder at a faster speed say 3 steps in one go, it either stays in the same brightness level or comes down a level . But does not do what it should. As soon as i disconnect the zero crossing pin it responds very quickly, i can see this in the step widget the number changing in sync with the encoder turns/steps

So i thought of using uno for processing bit and ESP to connect to wifi.
Assuming the dimmer worked fine on uno.