Ask HN: How would you go about making a mobile device single-purposed? | Hacker News Reader

Ask HN: How would you go about making a mobile device single-purposed?

13 pointsthinkloop9 comments

I would like to flash a mobile device with just enough software to run a single app. The app would load automatically in full screen when the phone boots, and the only functionality available on the device. No browsers, dialers, networking, stores, etc.

What kind of "app" needs to be built for this? Is core android the best starting point? Ecosystem compatibility has little importance here, perhaps something more suitable?

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Do you want to market such a device, or do you just need the ability to limit any device to a single app? If the latter, look into iOS Guided Access:

https://support.apple.com/en-us/HT202612

This. I have used simple HTML5 web applications with the meta tags to allow running in 'app mode' (no browser chrome etc) and then enabling guided access mode on iPads (mounted in display stands, mostly) many times, and find it works suitably well to lock the device to a single purpose. You need to consider a few edge-cases (for example not allowing text selection and long-press, which allows the user to access the 'look up' function, and making sure there are no links to any external URLs etc, but once you've covered off those things, it works as a fairly effective way to provide a 'kiosk' style interface.

> which allows the user to access the 'look up' function

Actually, the moment you enable Guided Access in Safari, it shows you a list of options specific to Safari, which includes disabling Dictionary Lookup!

It also allows you to disable hardware features like specific buttons, motion control, and even lets you draw on the screen to mark areas to disable touch input in.

Maybe it wasn't lookup, perhaps it was one of the share features, I don't remember exactly, just that it was possie to semi 'break out' by selecting some text and long-pressing to reach the context menu, even with all of the options disabled in guided access mode.

Interesting option! However I do need a wider selection of possible hardware than just iphone/ipad. Additionally, it is a security-related app, so part of being single purpose is not only for UX, but to remove as many vectors of attack as possible outside the minimum needed.

The Lifewatch MCT 1 Patch (https://www.lifewatch.com/Healthcare-Professionals/Mobile-Ca...) comes with a Kyocera Android (v5.1.1) phone that does exactly what you're describing.

Any reason you need it locked up so much? Can you just use vanilla AOSP and something to autolaunch your app?

It's a security related app, so the less unnecessary software the better, but that can be improved over time.

If I do use AOSP would the "app" be a real app, or would it be a custom "launcher" that replaces the desktop and app navigation screens (are those two things different or is the launcher just an app)?

I'm fairly certain the launcher is an app itself.

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