Not having fun/luck with ESP-8266 12E

[DJDJDJDJ]

Hi,

I am trying to configure an ESP-8366 12E to trigger a relay. I have no clue what I am doing wrong but I simply cannot make it fire one of the pins as intended.

Here is my simple code:

Code: [Select]




const int relay1Pin = 3;
const int relay2Pin = 4;
const int ledPin = 2;


void setup() {
  // initialize digital pin ledPin as an output.
  pinMode(ledPin, OUTPUT);
  pinMode(relay1Pin, OUTPUT);
  pinMode(relay2Pin, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(ledPin, HIGH);   
  delay(100);                       
  digitalWrite(ledPin, LOW);   
  delay(100);                       
  digitalWrite(ledPin, HIGH); 
  delay(100);                       
  digitalWrite(ledPin, LOW);   
  delay(100);                       
  digitalWrite(ledPin, HIGH); 
  delay(100);                       
  digitalWrite(ledPin, LOW);   
  delay(100);                       
  digitalWrite(ledPin, HIGH); 
  delay(100);                       

  digitalWrite(relay1Pin, HIGH);   
  delay(500);                       
  digitalWrite(relay2Pin, HIGH);   
  delay(1000);                       

  digitalWrite(ledPin, LOW);   
  delay(500);                       
  digitalWrite(relay1Pin, LOW); 
  delay(500);                       
  digitalWrite(relay2Pin, LOW); 
  delay(1000);                       
 
}



It is a very simple code to make the LED blink a few times and then trigger relays. I am using 2-relay module for this setup.

When I run this same code on Arduino Nano (changed led pin to 13), it works fine. LED flashed a few times and then both relays are triggered.

When I load it onto ESP, LED and Relay one trigger at the same time (same frequency). Relay 1 is not triggered at its intended frequency and Relay 2 does not trigger at all.

My hardware setup is pretty simple as well. It is simply to trigger the relays with nothing attached. I have attached images.

ESP unit itself seems to be working fine because if I load a wifi sketch, it will connect and acquire IP address. Just won't fire pins. I have been at this for a couple of weeks now. :-(

Thank you.

[DJDJDJDJ]

Here is the hardware setup

[Danois90]

What type of relays are you using? Arduino uses 5V logic and the ESP uses 3.3V - if the relays need 5V to activate that may be your problem.

I've inlined your images here:

[Deva_Rishi]

On an ESP (nodeMCU as you have) the GPIO pin nrs are there ones declared in the sketch, but they are not the same as the numbers printed on the board. Check the pinout You have connected the Relay to pins D3 & D4 those are GPIO0 & GPIO2 so either change that in you sketch or change the way you connect the relay (a bit of both would actually be best, i would not want to use GPIO3 because it is the RX pin and  GPIO0 is a pin that can not be pulled low during startup or the unit will go into FlashMode

[Danois90]

On an ESP (nodeMCU as you have) the GPIO pin nrs are there ones declared in the sketch, but they are not the same as the numbers printed on the board. Check the pinout

Yes, using the constants D2, D3 and D4 would eliminate this "issue".

[alex_fagard]

I'm finding it hard to follow all of your wires.

It seems like you need the following:

Breadboard power adapter 5V -> VIN/VCC on relay and to VIN/VCC on esp (assuming your esp module has a built in 3v reg !important).

Breadboard negative -> GND on esp and relay.

Now your relay is probably 5v, so you can't just connect it to a digital pin on your esp as those are all rated at 3.3v. This means, you'll probably have to trigger it via a transistor.

Something like:



If you don't have a npn transistor you can also use a mosfet.

Whether or not you've hurt your pins by feeding it too high of a voltage is another thing.

Please take what I've said with a grain of salt. I might not be entirely correct. If I am wrong, anyone can feel free to correct me.

[PerryBebbington]

Have you tried a multimeter on pin 4 to confirm it changes from 0 to 1 (0V to 3V3)? Better still an oscilloscope. A resistor in series with an LED to ground would be good too.

I found the pin out of the ESP8266s I have (different to yours) confusing. Maybe the outputs are not on the pins you think they are.

[anthonyHope]

I found the pin out of the ESP8266s I have (different to yours) confusing.

My nodeMCU is one of those early ones that's exactly the same width as a breadboard (is that v0.9 maybe,not sure), that is to say 2 pins too wide to be able to use it. So seeing as I had to mount it on 2x mini breadboards, I then stuck those on a bit of hardboard and glued the pin diagram to the back of that: it's the only way I can ever fathom out how to connect the bloody thing.

[DJDJDJDJ]

Hi all,

Thank you for your replies and suggestions. Here are a few of the answers to the questions raised.

My MCU and Relays are 5v. I was not aware that MCU gives out 3.3v on the pins. This could be one of my issues for sure. I have never worked with mofset or npn resisters so need to look these up and figure out which one I need ad ebay shows a boat load of different ones.

Another issue I see if probably the pin numbers as suggested above. Since I have worked with arduinos only and pin numbering on the board has not been an issue, I thought this would be same for MCU as well. I will check the  image mentioned above and also see if I can check it with multi-meter. I, unfortunately, do not have an oscilloscope. Yes, I have LEDs and resisters that I could use to test this as well. Thanks for the suggestion.

Hardware-setup wise it is pretty simple. Since MSU to as wide as the middle pins of the breadboard, I am using two breadboards. This fits perfectly and leaves me with enough room to attach wires. Breadboard rails are fed through power supply set to 5v.

I will come back with my findings.

[Danois90]

In order to fix the pin numbering issues, try this:

Code: [Select]

const int relay1Pin = D3;
const int relay2Pin = D4;
const int ledPin = D2;

A nice, cheap allround NPN transistor could be a BC337. The transistor needs to be in a "common emitter" (+5V switch) setup and not the "common collector" (GND switch) as the diagram in #5 shows. Alternatively you could look for a "logic level shifter" which will convert 3.3V logic to 5V and vice versa.

[PerryBebbington]

Unfortunately, do not have an oscilloscope

If you are serious about electronics as a hobby buy an oscilloscope. If you don't have a clue what to buy then either search these forums for advice (the subject has been discussed) or buy a cheap one. A cheap one will teach you 2 things: It will teach you how useful they are and it will teach you what features you need on a decent on. Then buy a more expensive one. Mine cost me about £250 for a duel input. 4 input would have been worth the extra cost however.

[DJDJDJDJ]

In order to fix the pin numbering issues, try this:

Code: [Select]

const int relay1Pin = D3;
const int relay2Pin = D4;
const int ledPin = D2;

A nice, cheap allround NPN transistor could be a BC337. The transistor needs to be in a "common emitter" (+5V switch) setup and not the "common collector" (GND switch) as the diagram in #5 shows. Alternatively you could look for a "logic level shifter" which will convert 3.3V logic to 5V and vice versa.

Thank you for the quick fix. I shall try it. I saw it in a couple of place but thought it was in error as we are defining the const as an int but assigning a string value. I am extremely new to electronics so don't even know what logic level shifter is. I will, however, check it out and order some BC337s as well. Thanks.

If you are serious about electronics as a hobby buy an oscilloscope. If you don't have a clue what to buy then either search these forums for advice (the subject has been discussed) or buy a cheap one. A cheap one will teach you 2 things: It will teach you how useful they are and it will teach you what features you need on a decent on. Then buy a more expensive one. Mine cost me about £250 for a duel input. 4 input would have been worth the extra cost however.

Thank you Perry. I will check it out. Since I am very new to this hobby, I am still collecting tools and equipment. I will look into getting one of these as well. Thank you.

[Deva_Rishi]

If your Relay board is of the type that i suspect it is (the type that includes an optocoupler) you can also modify it to take a 3.3v logic level by bypassing 1 of the 2 resistors (per channel) but to guide you with this you'll need a multimeter and we need a good close-up picture of the relay board (without the wires connected, they're obstructing the view)  Either way GPIO 0 is only usable as an output if the output is active-high which this relay board probably isn't.