This app provides a VT52 compatible Telnet client using a BLE keyboard and a Waveshare 4.3" LCD display: https://www.waveshare.com/wiki/ESP32-S3-Touch-LCD-4.3

The application is built using the Arduino IDE and requires the following board and libraries:

Esp32 by Espressif V 3.1.1

Arduino GFX librarty V 1.2

NimBLE-Arduino V 2.3.0

U8g2 V 2.35.30

You may get some errors that indicate other missing libraries.

Arduino configuration:
Device: Waveshare-ESP32-S3-Touch-LCD-4.3
Config: Upload mode UART0 / Hardware CDC + USB mode Hardware CDC and JTAG + PSRAM enabled.

Change line 43 in VT_Telnet_Client.ino to match the name of your BLE keyboard.
This is not an ideal way to connect to BLE devices as they commonly do not have a name.
To check the system out I suggest you connect a terminal app to the USB port on the Waveshare board.
You should see a list of local advertising devices from which you can find the name of your keyboard if you are not too sure.
Also, you will need to set the SSID/password/DNS server for you local router in Wave_Display.ino.
With a bit of luck, the app will find your keyboard, attach to your router and connect to your host.
At this point, the login prompt will appear of the display.
CapsLock is an issue with my keyboard as I cannot control the LED. You will not that a blue square appears in the display to indicate this state.
For this build, the cursor keys are setup as for a VT52 keyboard but the keypad is fixed in numeric mode.
To change this, look at src/key_codes.h and alter the text for keys on the last 3 lines of this file.
This app was originally built to connect to a UNIX and use vi. So, these keys are not required.
These are required for TECO/KED etc. but not for EMACS and (I think) EDT.

Best of luck as this is a slightly involved app using BLE/WiFi/DMA all at once!!

Ian Schofield March 20205