my project is getting data from sensors on Arduino UNO and passing those to ESP8266 (which are on the same board - Arduino Uno+WiFi ATmega328P+ESP8266 32Mb | laskarduino.cz this is the one I am using) and then sending those data to my RPi via POST.
My current approach is using LowPower library on UNO (GitHub - rocketscream/Low-Power: Low Power Library for Arduino) and ESP.DeepSleep() function on the ESP. However, this approach only allows me to put the UNO to sleep for only 8 seconds and I would like to extend this by sending external interrupt to the UNO from the ESP.
I found from googling that in order to do this you have to connect GND pins of both microcontrollers. But since the ESP8266 has only one GND and I am using it for the ESP.DeepSleep() function I have no spare GND left.
My question is - do I need to connect UNO's GND and ESP's GND or they are somehow connected when installed on the same board? I am asking this because I dont have any equipment to duplicate the GND pin on ESP8266 at the moment.
Sorry if this is a dumb question, I am just starting with this whole Arduino thingy
Thank you for your responses!