help with HID braille for open source devices for people with disabilities

discapacidad5 · December 6, 2021, 4:09am

Hello, I am developing a device for people with disabilities. I need to use the HID braille protocol but I am not getting anything with HID for esp32, could you help me with a sample code of how I can implement the HID braille protocol?

here are references to braille HID

github.com

nvaccess/nvda/blob/00cd67b737bc5b23a6f5e31cf28110b64ebf2fee/devDocs/hidBrailleTechnicalNotes.md

HID Braille Developer Notes

## HID (Human Interface Device)
The HID specification standardizes the low-level communication with a USB or Bluetooth device, plus the types of input and output controls on the device.
Example devices being keyboards, mice, screens, and now Braille Displays.

### Definitions
In this document, device means a piece of hardware that connects to a computer via a connection such as USB or Bluetooth.
The device may contain one or more Controls for a human to physically communicate with the device, such as buttons or keys for input, or LEDs or cells of raised Braille pins for output.

There are also several terms in HID which may be confusing to those just beginning to familiarise themselves with this technology.
* Descriptors
* Usage pages
* Usages
* Reports
* Collections
* Caps (Capabilities)

These terms are described in the subsections below.

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my repository is the following

htibosch · December 6, 2021, 5:37am

Hello @discapacidad5, I hope for you that there is a Braille HID expert among the readers of this post.

If not, you might want to find a different forum or users group. This forum is about FreeRTOS and related subjects.

I only have experience with HID: I use it in a raw mode in which I can send packets of 64 bytes to my embedded device and vv. Very nice because it doesn’t need a driver on the host side.

I am sure that there will be open-source USB/HID drivers for the ESP32. I guess that the Braille driver sits on top of it?

Good luck!

benedekkupper · December 7, 2021, 9:13pm

You should be able to find an HID project for ESP32, I haven’t worked with that platform yet. Then you can replace the HID report descriptor to something similar to this: Support Braille displays that conform to the HID Braille standard by michaelDCurran · Pull Request #12523 · nvaccess/nvda · GitHub and implement HID report receiving and transmitting based on the contents of the descriptor.

discapacidad5 · December 7, 2021, 10:48pm

Thanks for your reply
My problem is that I do not know anything about HID, I am a programming baby, there is documentation but I do not understand them. I pass a documentation reference here to see if they know how I can do it. My device has the same buttons and braille cells as the focus 40

I would like a model code that I can adapt to my needs.

The initial example can be Espressif:
github . com /espressif/esp-idf/tree/master/examples/bluetooth/bluedroid/ble/ble_hid_device_demo
In it we have everything you need to get started on a mouse / keyboard project.

Please try to compile and update the sample to ensure a successful development setup.

(introduction to ESP32: docs.espressif. com /projects/esp-idf/en/latest/esp32/get-started/index.html)

And then you need to change the HID descriptor to the HID braille documentation example.

I have created a blank repository within my project for anyone who wants to help me
github com brailletouch HID-braille-ESP32