You download and launch Obtanium. You tap on ‘Add App’. You copy/paste https://voiceinput.futo.org/ into the ‘App Source URL’ field and click on ‘Add’. Now, this might take some time, maybe a few minutes. Then you should be able to install the app. Obtanium will notify you whenever an update is released, and it will also allow you to download and install the new version.
I would like to see an F-Droid release as well, but in the mean time you can use Obtanium to pull the APK right from the Futo website.
They have their own F-Droid repo listed on their website (https://voiceinput.futo.org):
https://app.futo.org/fdroid/repo?fingerprint=39D47869D29CBFCE4691D9F7E6946A7B6D7E6FF4883497E6E675744ECDFA6D6D
How? I couldn’t get it to work.
You download and launch Obtanium. You tap on ‘Add App’. You copy/paste https://voiceinput.futo.org/ into the ‘App Source URL’ field and click on ‘Add’. Now, this might take some time, maybe a few minutes. Then you should be able to install the app. Obtanium will notify you whenever an update is released, and it will also allow you to download and install the new version.