mt63_wasm

This is very much a work in progress; the idea is to compile a mt63 library to wasm using emscripten to allow encoding MT63 messages and "sending" them from an HTML5 audio web application; this could be used to reliably transmit data from a smartphone app across Amateur Radio FM signals on VHF/UHF.

Release notes

• 1.5.0 - Add support for downsampling in WASM code
• 1.4.0 - Rebuild using a newer more optimized version of emscripten
• 1.3.3 - Misc updates to allow customization of the emscripten load Module
• 1.2.2 - Fixed broken wasm binary on iOS

Preparing to build

Currently we have it set up to build on linux or macOS.

First you need to have cmake installed. Next, check to see what versions :

cd emsdk_portable
./emsdk list

Install the correct sdk version for your platform. We're building on macOS successfully using:

./emsdk install sdk-1.38.4-64bit

Note that we've had issues with iOS on later builds

Building

Once that's done, building is a simple two-step process:

./prepemscripten.sh
cmake --build build/

You should now have a build/ directory. Copy index.html into the build/ directory and run some sort of static web server there. I use node-static: npm install -g node-static. If you have node-static installed you can start a server like so:

cd build/
static .

Open http://localhost:8080 in your browser, open a console, and run sendMessage("This is a test message"); You should hear the mt63 come through.

Status

This is being used by the Runner-tracker app. To use, do something like this:

/// <reference types="webassembly-js-api" />
// The above is to get types for WebAssembly -- fix this however works for you

// tslint:disable:no-var-imports
// tslint:disable:no-var-requires

import {
    setFileLocation,
    initialize,
    MT63Client,
} from 'mt63-wasm';

import {
    wasmModule,
} from 'mt63-wasm/dist/wasmModule';

const wasmFile = require("mt63-wasm/dist/mt63Wasm.wasm");

setFileLocation("mt63Wasm.wasm", wasmFile);
export const readyDfd = initialize();

export {MT63Client, wasmModule};

You may need to update your webpack config to override the type for the webassembly file to "javascript/auto" and use "file-loader" to load it to make this work. Our vue.config.js file looks like this:

module.exports = {
    publicPath: process.env.GITLAB_CI ? '/runner-tracker/' : '/',
    chainWebpack: config => {
        config.module
            .rule('wasm')
            .test(/\.wasm$/)
            .type("javascript/auto")
            .use('file-loader')
                .loader('file-loader');
    }
};

Shameless plugs

This project relies heavily on the fldigi MT63 code and was put together by Richard Bateman, founder of HamStudy.org. To support our efforts, check out https://signalstuff.com/antennas (our main source of funding) and https://hamstudy.org/appstore for well engineered study apps for only $3.99. HamStudy.org is sponsored by Icom, which means that in a round-about sort of way Icom also sponsors this project =] They really do a lot to build the ham radio community in the US so support them in whatever ways you can!

License

mt63-wasm is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

mt63-wasm is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this project. If not, see http://www.gnu.org/licenses/.