Connect UNO R3 to Wemos D1 R!


I have been trying to connect my R3 with Wemos D1 R1 (ESP8266 based wifi) Board. But I am struggling to find the correct pins.

I tired looking for solutions but could not get it. The only solution was

I am using R3 because I have to get data from 3 sensors and D1R1 offers only 1 analog input.

I tired wiring as per How to connect an ESP8266 to an Arduino UNO — Teo's blog but i am getting nothing on the serial monitor.

The forum thread that you liked is for I2C communication. The “diagram” is for serial communication. Serial is probably easier for a new user.

I would use a software serial port to talk to the D1 and save the hardware serial (USB) for program upload, monitoring program flow and variable values and debugging.

Is the D1 5V tolerant? If not you will need level shifting between the D1 and 5V Uno.


I was able to do it by making R1 D1 as Master Receiver and Uno R3 as slave sender.

Used this Blog for help.