This project is based on my old 2D-LoRa-Pager idea:
LoRa did not worked out in combination with the TFT screen. So i used Bluetooth as a fallback solution.

2D Pager upgrade - New: a receiver indicator. Get noticed if someone is drawing something to you:

With Bluetooth Sync:

Without Bluetooth Sync:

The ESP32 dose has Bluetooth it self, but i was going a way i already had gone before, so i used the BT-module. With that decision i also can use one code for both devices. That made thing more simple.

Halloween special: 

The case is 3D-printed. I used a scaled up .stl from Dustin Watts ESP32 Touchdown files. I used a scale factor of 110% in x- & y- and 100% in z-direction. But better check yourself for an exact fit of the 4" TFT.

To pre-pair the HC-05 modules i was following this tutorial: 
Keep in mind the Rx Pin of the module is 3,3V tolerant. I also set the baud-rate to 115200.

It seems that when i transmit from the BT-module Slave to Master the draw line are appearing instantly. The other way around its lagging about 200 ms behind.