Anyone who has set up a Raspberry Pi Zero W will know it is a bit limited by IO, such is the trade off for such a small form factor. I recently went through a set up that was especially awkward as there was no WiFi available. I tried to use an Android hotspot but unfortunately the Pi could not see the Android device at all. The only option I had was to tether the Pi to the Android via USB. This worked. The Pi had access to the mobile data of the Android device however it seems that the power draw from the Android device meant there was not enough power left to power the wireless USB receiver for the keyboard and mouse combo. So I was left with mutually exclusive options of either access to the internet or the ability to use a keyboard and mouse. Luckily there is always a plan C.
You will need a mouse that can connect to the Pi either by USB or Bluetooth. The OS used was Raspbian but this solution should work with other Distros.
The Raspberry Pi Zero W also comes with Bluetooth built in so there was the option to make the Pi discoverable and connect a Bluetooth keyboard and mouse. I do not have a physical Bluetooth keyboard or mouse but thankfully there is an App for that, multiple ones actually.
The App I used was the “Serverless Bluetooth Keyboard & Mouse for PC/Phone” from Google Play, available here.
It is free (with ads) and very easy to set up. In terms of performance it provided me with a usable keyboard (like Gboard) with half of the device screen acting as a very responsive track pad. I certainly would not want to compose a thesis with this setup but for typing a few words and clicking a few links it is perfectly serviceable.
I experienced what maybe a slight bug during set up however but I resolved the problem in a minute or two.
Problem and Fix:
Firstly you will need to make the Pi discoverable via Bluetooth. This is the only time I needed to make use of a physical mouse. The option to turn on Bluetooth and make the device discoverable is to the top right of the Raspbian Home screen.
When I tried to connect the Android and Pi together through the App it would not work. The Pi was not discoverable by the App despite the functionality to discover devices being built in to the App.
To connect the devices I first had to connect the Android device and Pi together via their respective operating systems. This threw an error on the Pi but the Android device was visible to it. I then removed the Android Bluetooth connection from the Pi and again tried connecting the Pi via the App. This worked.
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2 thoughts on “How to use an Android device as a keyboard and trackpad for a Raspberry Pi”
Nice one just tried doing similar with pi400 (connected to projector so really hard to access) but no matter how ive tried still got no luck
Thanks for this post! I gave up hopes with the android app after mine showed connecting but won’t connect. Glad to read this post. Strangely enough, it started working after removing and re-pairing.