ESP8266 Community Forum

- Wed Mar 01, 2017 3:18 am #63168 Hello.
I want to connect my Wemos D1 with this relay board (4 channel type)
http://www.icstation.com/icstation-micr ... -4012.html
I power the Wemos with a 9V external input and the board with an USB adapter.
To prevent voltage problems I use a voltage level shifter module.
the connections are as follow:
Wemos <--> Level shifter
GND -> GND
3.3 -> LV
RX -> L1
TX -> L2

Relay board <-> Level shifter
GND -> GND
5V -> HV
RX -> H2
TX -> H1

Now I want to use SoftwareSerial to avoid conflicts with the serial interface for debugging purpose

Code: Select allport=new SoftwareSerial(serialin, serialout);
pinMode(serialin, INPUT);
pinMode(serialout, OUTPUT);
port->begin(9600);
port->write(0x50);
port->write(0x51);
// turn relay on
port->write(0x00);


The relay module works well with a python script from the PC.
Any clues?

thank you for your time!

- Thu Mar 02, 2017 6:53 am #63227 Without more information, my only suggestion is to check that you crossed your RX & TX lines.

- Thu Mar 02, 2017 10:33 am #63235 Yes, I crossed RX and Tx,
as in my previous post

RX -> L1
TX -> L2
RX -> H2
TX -> H1

I can provide more information, what do you need?

- Fri Mar 03, 2017 6:58 am #63287 I don't believe that sketch will work with the current SoftwareSerial library. Check out this reference: https://www.arduino.cc/en/Reference/softwareSerial for the example code. I don't think you should set the pinMode after setting up the softwareSerial.