ESP32 BT-HID Device

[gitmh]

Is it possible to use the ESP32_BLE_Arduino library to build a HID-Keyboard to send keystrokes to another device? My goal: I would like to connect a ESP32 board to a BT device like an iPad and send a space character. I found https://github.com/asterics/esp32_mouse_keyboard but can't figure out how to this running in Arduino IDE. Any help would be appreciated - I found a lot of users asking for a similar feature for the ESP32.

[nkolban]

I'm afraid there is nothing yet in the BLE C++ classes that would make your request possible. Maybe a question posted to one of the forums here might give some positive results:

https://esp32.com/index.php

It is my loose understanding that HID support is based on Bluetooth classic (BR/EDR) as opposed to BLE and, so far, these classes only cover BLE functions.

[gitmh]

Thank you very much @nkolban. I already found a project for esp-idf for HID and BT but I was hoping for an example for the arduino IDE. I have no experience with IDF and the tool chain and how to integrate those stuff with arduino. Maybe this will come in the future.

[nkolban]

Do you have a link to the HID and BT project that uses ESP-IDF? I'd like to file that and have a look to see what it would take to eventually encapsulate that in the C++ libraries. That would be the first step towards an Arduino encapsulation.

[gitmh]

The most complete and supported solution seems to be the BTStack port for the esp32 for IDF here
https://github.com/bluekitchen/btstack/tree/master/port/esp32 within this library there are various examples for HID devices and other BT applications.

[nkolban]

OOOh thats cool. But scary as well. If I get a sense of that story, it is a replacement for the Bluetooth stack supplied by Espressif (which I believe is based on Bluedroid stack implementation).

[gitmh]

Yes so this might be a problem to have both stacks available at the same time in an Arduino library. The example under https://github.com/asterics/esp32_mouse_keyboard uses the bt.h from the regular Espressif library so (see ble_hidd_demo_main.c).

[chegewara]

New day, new lessons:

My esp32 just become HID keyboard. ANd now its HID mouse:

Of course its not real keyboard and mouse, but my windows 10 is stupid and thinks it is ;)

[gitmh]

@chegewara Have you build an Arduino project for that already? I would be interested :-)
Sending a keyboard key to any BT device like an iPAD would be a great use case for the ESP32.

[chegewara]

Oh no, just fooled my laptop by setting appearance(). The rest of code has nothing to do with hid keyboard. But i may do some research and see if this is hard to do.

[chegewara]

I have some good news and some bad news. Good news that work is in progress. Bad news is driver crash under windows with error code 0x0a(device cant start). I can say for sure what is the reason, but its a chance that hid keybord requires secure connection and we dont have implemented it yet.

My next step will be to rewrite code in esp-idf and see what happen and maybe add some security there.

EDIT more good news, my samsung s4 connects to esp32 hid keyboard, so now i have to find way to send some text

[chegewara]

I have good news. Esp32 hid keyboard is connecting with my android phone and i can send text. This mean hid keyboard works, at least software part. Still is some work to do but we know it can be done.

[gitmh]

@chegewara great work, would you share your current project to play around with it? I just need a running starting point for the Arduino IDE :-)

[chegewara]

Im not sure yet, i will provide code or share links ive been using during research. Im thinking about writing blog article about this. For now maybe this will help you a bit:
https://github.com/I0x0I/DIY-A-BLE-Keyboard

https://docs.mbed.com/docs/ble-hid/en/latest/api/md_doc_HIDService.html