send values from arduino uno to wemos d1 r1 I have a weather project in which I have to measure the temperature and humidity ( dht22 sensor ), the pressure and other things and then show them in a local web page ( usings wemos d1 r1 ) in either my phone or pc ( I have both Arduino uno and Wemos d1 r1 for this project )
I wanted to use only wemos d1 r1 since it works the same as arduino uno except it has an esp8266 Wi-Fi built-in while arduino uno doesn't have ,but as you may know it only has 1 analog pin while I need at least 3 or 4 analog pin so in my case i should connect the sensors with the arduino uno and measure the temperature, humidity etc .. and then send those values to the wemos d1 r1 which will show the results itself in a web page as I said eariler
It seems that there is a way to do that using I2C connection but I have read many articles talking about connecting arduino to another arduino using I2C connection but I don't know how to do that in my case ( Arduino uno and Wemos d1 r1 ) and if there is another way to send values please tell me
As I see it, the most straight-forward way to connect 2 Arduinos is using their built-in UART (aka Serial port, TX/RX pins) communication.
There are many tutorials on this on Google, and a similar explanation can be found in this question:
Serial communication arduino mega and D1 Wemos Mini
However, there is a slight difference.
Arduino Mega has built in more than 1 hardware serial ports (I can't recall now if it's full 3 ports, or just 2), what leave one port for debug purposes, and the other - for your communication.
In your case (Arduino Uno) - you have only one serial port, that if will be used for the inter-Arduinos communication - will not be available for debug/console messages.
The solution for this is adding a Software Serial port, also highly available in tutorials over the net, here is one example:
softwareserial between arduino uno and esp8266
Enjoy your project!