This repo allows you to make a Pi Zero W (2) appear as a USB media remote control. It can then be plugged into devices like an Android TV or Fire TV and used to control it over the network.
- A Rasberry Pi Zero W or Rasberry Pi Zero W 2 (it may also work with a Pi 4 but I've not tested this)
- A way to connect the Pi Zero to the device to be controlled.
- For Fire TV I used this cable: FireTv OTG Cable
- For Google Ghromecast with Android TV I use this adapter: Chromecast with Google TV OTG Cable. This also allows you to use Wired Ethernet
First install a minimal Linux OS on the Raspberry Pi Zero - I use DietPi with no extra software installed and connect it to your WiFi.
ssh to your pi and clone the repo
cd ~
sudo apt-get install git
git clone https://github.com/foxy82/pi-usb-gadget-controller.git
Setup the pi so that it will behave as a USB Gadget.
cd ~/pi-usb-gadget-controller
./install_usb_gadget.sh
Get the required packages first
sudo apt-get install python3 python3-pip
sudo pip3 install pi_usb_gadget_controller
cd ~/pi-usb-gadget-controller
sudo pip3 install .
The above will install anm executable called UsbGadgetController. Running this will start a server on the default settings - you will need to run as sudo to access the USB gadget device or setup permissions to access it as a regular user.
$ sudo UsbGadgetController
There are some options that can be set
$ UsbGadgetController -h
usage: UsbGadgetController [-h] [--device DEVICE] [--web_port WEB_PORT] [--socket_port SOCKET_PORT]
[--logging {DEBUG,INFO,WARNING,ERROR}]
Send commands to a USB Gadget
optional arguments:
-h, --help show this help message and exit
--device DEVICE The USB Gadget device. DEFAULTS to /dev/hidg0
--web_port WEB_PORT The port to start the web_port on. DEFAULTS to 8080. NOTE if you specify a port here you also need
to spcify a --socket_port otherwise the socket port won't be opened
--socket_port SOCKET_PORT
The port to start the socket server on. DEFAULTS to 8888. NOTE if you specify a port here you also
need to spcify a --web_port otherwise the web port won't be opened
--logging {DEBUG,INFO,WARNING,ERROR}
The logging level to use. DEFAULTS to INFO
You can install the server as a service to run on start up:
cd ~/pi-usb-gadget-controller
sudo ./install_service.sh
This will use the default options. To change the options edit ~/pi-usb-gadget-controller/usb_gadget_controller.service and edit the ExecStart line then run ./install_service.sh (first install) or ./update_service.sh (updating)
Shutdown the pi and then connect it to the device to be controlled using a data usb cable and using the data usb port on the Pi Zero (the one nearest the HDMI port on Zero W and Zero W2)
This app provides several ways to receive commands and currently supports the following:
- UP
- DOWN
- LEFT
- RIGHT
- SELECT
- HOME
- BACK
- PLAY
- MUTE
A socket interface is provided on port 8888 (by default).
It will accept commands in the format:
<key_state>|<key>\n
Where key_state is one of:
down- Key has been pressed downup- Key has been releasedhold- Key is being heldpress- Key was pressed and released
key is one of the commands listed under Usage above.
e.g. example commands.
down|SELECT\n
up|SELECT\n
press|HOME\n
A websocket interface is provided at http://ip:8080/ws it will take the commands in uppercase e.g. UP, DOWN
A REST API is provided by doing a GET at http://ip:8080/rest/ where command is the key to send e.g. UP, DOWN
You can also do plain GET requests to http://ip:8080/get/ where command is the key to send e.g. UP, DOWN. This call will provide a redirect to a web page (see below)
The app also provides 3 web pages with remote buttons to click and send commands:
- http://ip:8080 - is a web page using web socket for communication - it should be the fastest to use
- http://ip:8080/js - is a web page that uses JavaScript to make REST calls in the background - I have sometimes seen Chrome take up to 1+ seconds to actually send the command so WebSocket is prefered if you can use that.
- http://ip:8080/get - Sends GET requests and reloads the page on every click. Likely to be slow but will work if you don't want to use JavaScript or WebSockets.
This is a work in progress so there might be times when updating is more complex. However you can try running ./update.sh from the root of the git repo.
The best bet is to just write a brand new OS onto the SD card however if you do need to remove...
cd ~/pi-usb-gadget-controller
sudo ./uninstall_service.sh # Only if you installed this as a service
sudo ./uninstall_usb_gadget.sh # Follow the additional instructions
sudo pip uninstall pi_usb_gadget_controller
Things i'm working on for this:
V2 of the API to allow pressing and holding(in v 0.3.0)- V3 of the API to allow keyboard keys to be sent.
- V4 of the API to allow mouse events (possibility if I decide I need this)
- A seperate app which will take input from a 2.4 GHz USB remote and transmit it to this app(in progress)
- Using a Pulse Eight USB CEC Adapter to take CEC commands and send it to this app.
- Use protobuffers to make it even more responsive (not needed at the moment)
- Moon shot - can we add a way for a mic to send us audio data so that we could do a voice search?
Links that helped me come up with this solution
- Tutorial here on how to use the pi zero as a usb gadget - [https://www.isticktoit.net/?p=1383]
- Tutorial for someone doing volume control: https://www.ekwbtblog.com/entry/2019/01/31/000000
- Two tutorials on the report descriptor: [https://notes.iopush.net/blog/2016/custom-usb-hid-device-descriptor-media-keyboard/] and [https://eleccelerator.com/tutorial-about-usb-hid-report-descriptors/]
- Tool to decode the report descriptor: [https://eleccelerator.com/usbdescreqparser/] (need to replace \x with space for the tool)
- To find keycodes: [https://www.usb.org/hid] document is titled "HID Usage Tables 1.22" we need section 15 "Consumer Control"