A virtual bingo-blower for ambiguity and risk experiments.
https://geoffreycastillo.com/bingo-blower-js-demo/
bingo-blower.js uses matter.js and its plugin matter-attractors.
Refer to their respective pages for instructions on how to install them.
Then, download bingo-blower.js from the releases and include it:
<script src="bingo-blower.js" type="text/javascript"></script>
or use a CDN such as jsDelivr:
<script src="https://cdn.jsdelivr.net/gh/geoffreycastillo/bingo-blower-js/bingo-blower.min.js
"></script>
# html
<canvas id="world"></canvas>
<button type="button" id="draw">Draw a ball</button>
The ball drawn is: <span id="result"></span>
# js
<script src="https://cdn.jsdelivr.net/npm/[email protected]/build/matter.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/[email protected]/build/matter-attractors.min.js"></script>
<script src="https://cdn.jsdelivr.net/gh/geoffreycastillo/bingo-blower-js/bingo-blower.min.js"></script>
<script>
let blower = new BingoBlower();
blower.addBalls([1, 2, 3]);
document.getElementById('draw').addEventListener('click',
async () => {
const draw = await blower.drawBall();
document.getElementById('result').innerHTML = draw.colourHuman;
}
);
</script>
See the wiki for specific oTree advice.
Create a bingo-blower with bigger balls: let blower = new BingoBlower({'ballSize': 30}); (you will also need to increase windForce or decrease density because bigger balls are heavier!)
Add a lot of balls: blower.addBalls([10, 15, 20, 25]);
Same number of balls but base-64 encoded: blower.addBalls('WzEwLDE1LDIwLDI1XQ==');
Add balls and specify your own colours: blower.addBalls([1, 2, 3], ['MediumVioletRed', 'HotPink', 'Pink']);
See the wiki for the API documentation and for some advice when using in an experiment (e.g. in oTree).
The attractor force (the wind blowing at the bottom of the bingo-blower) depends on the screen refresh rate. We have calibrated it for the most common one: 60Hz. At lower refresh rates (e.g. 25Hz), the balls will appear to move slower, and at higher refresh rates (e.g. 120Hz), they will appear to move faster.
Also, bingo-blower.js might not work on old browsers (e.g. IE11).
If you use bingo-blower.js in an experiment, you can (and maybe should) control for these.
Head over to the wiki for advice on how to do that.
If you use bingo-blower.js, please cite our paper: Andersson, Castillo and Wengström, "Generating ambiguity with a virtual bingo blower"
Open an issue or a pull request, or email me at [email protected].
bingo-blower.js is licensed under the GNU General Public License v3.0.
Copyright (c) 2022 Geoffrey Castillo