In this project you’ll learn:
A variometer (or vario for short) is a flight instrument. They are pretty complicated and expensive. You can learn a little bit about them here if you are interested.
Varios are used by all sorts of pilots. We’ll be building a very simple vario that would be suitable for use by noob paragliders without any money.
The main function of the vario is to make different beeping noises depending on if the pilot is accelerating upwards or downwards. This is useful because the pilot will often be quite high up so there isn’t an easy way for them to just sense if they are accelerating upwards or downwards, they don’t have a frame of reverence. The vario’s beeping aims to give the pilot a 6th sense about their vertical acceleration.
This is useful because the paragliding pilot needs to be able to find air that’s rising so that they can catch some lift and stay airborne for longer. If a pilot cant find any lift then they have to land.
Please create a vario that does the following:
One of the really cool things about Expo is that it supports many device apis. All the crazy stuff mentioned above can be accessed using regular JavaScript.
You’ll need to make use of the following:
Take a look here:
https://freesound.org/search/?q=beep
Find two different sounds you like and download them. You can just make a free account. If you want to get your noises from somewhere else then that’s totally fine as well.
This is going to take a bit of experimentation to get right. It would be useful to work on one thing at a time. And then once you have figured out each piece, bring it all together.
First, get the sounds to work. It might be useful to make two buttons, clicking the first button should make the “up” noise, and clicking the second button should play the “down” noise. Make sure that you can play the up noise multiple times by clicking the up button multiple times.
Once you have the sounds down then start figuring out the accelerometer. To do this you’ll need to make use of the expo-go app on your phone.
When you start your app withyarn start then you will see a QR code come up in your terminal. Make sure that your phone and computer are connected to the same wifi network and then scan the QR code with your expo-go app. When you do this then expo will open a page in your web browser, you can use this page to control the app that is running on your phone.
Open up the devtools (F12 in chrome) and make sur you can see the console.
Now update your code so that whenever you get a reading from the accelerator, you console log it. You’ll be able to wave your phone around and see how the acceleration data changes by watching the console.
Once you understand how acceleration works, you’ll just need to trigger your noises at the right time. That’s it.