A toy project to drive Sense Hat's LED matrix by using Go/JS.

This project consists of 2 parts:

• A simple mobile front-end based on P5 that can modify the matrix data for 64 LEDs on Sense Hat.
• Golang based web server with REST APIs that accepts the configuration from the front-end and controls the LEDs via I2C.

An image can make more sense than the description above.

• The simple mobile web front-end has 64 dots that represent the 64 LEDs on Sense Hat.
• Users can choose which LEDs they want to control for the color with the 3 buttons such as All, Partial, and Single.
• The colors can be changed by the 3 sliders as well as the buttons below that can flip and turn the matrix.
• Lastly, there is an Apply button that sends the data to the RPI server (then the Go app takes the data and controls Sense Hat via I2C).

Here is a link to Youtube that shows its actual behavior.
https://youtu.be/xrmaou6DVRc

The readers can try this project with their RPI and Sense Hat.

To properly reproduce this project, readers should have these hardwares:

• A host PC that has software to build this project
• A Raspberry Pi with a micro SD card that has more than 8 GB to store Raspbian stretch
• A Sense Hat
• Cables for power, network, and serial terminal

The PC should have these tools:

• Go SDK (1.12 is the latest official version as of March 2019)
• VSCODE (+ Go and SFTP extensions)
• Web Browser (Chrome/Chromium)
• SSH/SFTP client
• Git client
• Should be connected to your router

The RPI should have these tools:

• OpenSSH server that has port opened as you want (not 22 though...)
• Should be connected to your router (Please note the IP address)

First, clone this repo to the host.
Typically you can use the git command in Linux/Mac.

git clone https://github.com/bus710/matrix

Open this repo with VSCODE.

code $PROJECT-ROOT/server

Assumingly the host has Go SDK and ready to build this repo.
If so, press CTRL + SHIFT + B, then VSCODE will show you a dialog to build for x64 or ARM (Please pick matrixARM).

To push the matrixARM binary and the web contents files, a file (server/.vscode/sftp.json) should be generated (CTRL+SHIFT+P) and changed to point the RPI's IP address.

{
    "name": "upload to rpi",
    "host": "192.168.1.76",
    "protocol": "sftp",
    "port": 2222,
    "username": "pi",
    "remotePath": "/home/pi/",
    "uploadOnSave": false,
    "privateKeyPath": "~/.ssh/test",
    "passive": false,
    "interactiveAuth": false,
    "syncMode": "update"
}

The host and port should be updated regarding the RPI.

The host and RPI should share a SSH key to use the SFTP extension.

ssh-keygen -t rsa -b 2048 -v
ssh-copy-id -i .ssh/test.pub [email protected] -p 2222
ssh -p 2222 [email protected]

If the key was well copied into RPI, the last command makes your terminal to log in to RPI without password.

From VSCODE,

• righ-click the matrixARM generated from the file explorer and click Upload.
• Repeat the same action for the public directory.

From RPI's terminal, run below commands:

chmod 744 matrixARM
./matrixARM

From Web browser, access to http://192.168.1.76:8080.
(Pleae note that the address should be changed as your case).

If you see a screen from your browser as same as the image example in the beginning, you are ready to play with that, enjoy!

Disclaimer

This is just a toy project that cannot be used for safety/commercial products.   
The developer doesn't take any kind of (phsical, mental, and financial) responsibility.