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

You need emscripten and cmake installed and in your path -- it will try to use emcmake to set up the build directory

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/.