# Overview
Send a message between 2 projects
## Group project
The common project we have is an ESP32 hooked up with an RGB LED. The ESP32 conencts to my mobile hotspot, connects to a local MQTT broker and
subscribes to an MQTT topic called `attiny1614/led`, takes that value and blinks the LED 3 times with that particular interval.
Below is a diagram of the ESP32 we are using.
Below is the physical wiring diagram:
- ESP32 GPIO19 -- B channel of RGB LED
- ESP32 GPIO23 -- G channel of RGB LED
- ESP32 GPIO18 -- R channel of RGB LED
- ESP32 GND -- GND pin of RGB LED
Below is a video of the ESP32 subscribing to the MQTT topic `atting1614/led`.
## Integration with Bryan's project
Bryan: From my fabricated ESP01 board, I am waiting for messages from Serial port. When I receive the message, I publish it to the MQTT topic `attiny1614/led`,
which then makes the LED blink 3 times. For demo purposes, I've sent the same exact 3 messages from ESP01 to the ESP32.
Some screenshots are added below as the video might be too blurry. The images are purposely left big to be easier to see the values (and potentially refer the video).
First information sent: 1234