Plasma Ball as a Touch Sensor
A plasma ball (also called plasma lamp, globe, sphere) is a clear glass container filled with a mixture of various noble gases with a high-voltage electrode in the center of the container. It was invented by Nikola Tesla and was quite popular in the 1980s. It was often a standalone exhibition in a science museum.
However, now in 2019, we have a different way to use it. As the title suggests, we use it as a touch sensor to create interactive objects.
How it works
When you touch a plasma ball, the plasma filaments will be more brighter and be attracted by your hand. If you use an ammeter to measure the current of the plasma ball, you will find that the current is higher than normal when the plasma ball is touched. So we can measure the current to detect if the plasma ball is being touched or not.
Hardware Requirements
We build a prototype extension board for the Pitaya Go, and then turn a Plasa ball +a Pitaya Go + an extension board into a touch sensor. It works quite well.
As the Pitaya Go supports USB, BLE and Wi-Fi, it is very convenient to connect the touch sensor with other objects.
The first thing in mind is to turn it into a USB or BLE one-key keyboard, so you can easily use it with your computer or even your phone. You can also connect it to the Internet with Wi-Fi, and use with IFTTT.
First thing first~ Writing code to turn Pitaya Go into a USB Keyboard. The source is at https://github.com/xiongyihui/plasma_ball_touch_sensor. It is based Zephyr RTOS.
Use it as a USB one-key keyboard to Play Floppy Bird
It would be cool to use the plasma ball with games and musics. The first try is to play floppy bird with it. I programmed the Pitaya Go as a space key. When the plasma ball is touched, it will send a space to the computer. Here we go.
Floppy Bird
- js version: https://github.com/nebez/floppybird
- python version: https://github.com/404-Program-not-found/Flappy-bird
Play Chrome Dinosaur Game with it
When you are using Chrome but are offline, you will see the dinosaur game. You can also enter the URL chrome://dino/ to play it without going offline. It is a perfect game to play with the plasma ball!
Next step
So what’s next? If you are interested, I can write a step by step guide to setup hardware and software to get it work, or build another demo with the Plasma Ball Touch Sensor, for example, a divination magic ball with voice interaction.
What do you think?
