I have two perfectly working phones (old Samsungs, one S9+ and another one I forgot the model).
I would like to turn them into mini dashboards.
Is there specialized/minimal firmware that would provide strictly the needed OS and browser (or kit) that would allow to plug in a URL and go from there?
What do you use on these mini-dashboards?
I have 2 old androids that I use around the house. I just stripped them of any app I could and removed all account info that I could find, install companion app, create an HA user for that device to log in with, and set up a dashboard that’s sensible for that screen size and the area it lives in. I’ve also set them up with assist for voice control. This works great for me.
Thank you. Have you used some special browser or just Chrome/FF? How do you make the display on/off?
I use kiosk-satellite. It’s really great for displaying a dashboard and having a voice assistant.
You can configure quite a few things, including entity filtering; that way, if your phone is a bit older, it will handle your dashboards better.
On the browser question: you don’t need a special browser so much as something that stays put. Chrome or Firefox render a dashboard fine, but a stray tap wanders off it, and neither gives you any say over the screen. That’s why people here end up on the HA companion app in kiosk mode, on kiosk-satellite as stban1983 suggested, or on a dedicated kiosk app.
The display on/off half is the harder one, and the constraint is worth knowing up front: without device-admin privileges an Android app can’t truly power the panel off. What it can do is hold the screen on and take the brightness to zero. On your S9+ that is a better outcome than it sounds, because it’s OLED — black pixels at zero brightness are genuinely off, so the panel draws almost nothing and a static dashboard can’t burn in. On an LCD phone you get the look but the backlight stays lit. The companion app also exposes screen commands on Android; worth reading its docs for what they do on the Android version each phone is actually running, because that has moved around over the years.
So the pattern that works is: keep the screen on permanently, and let HA decide when it shows the dashboard and when it shows black, driven off a motion or occupancy sensor.
Disclosure: I’m the developer of HAkiosk (Android and iOS, commercial — not free, not open source), so weigh this accordingly. It’s the piece of your question I actually built, so here’s the concrete version: it subscribes to an MQTT command topic and accepts {“action”:“screensaver”} and {“action”:“wake”}, plus {“action”:“url”,“url”:“…”} to swap the dashboard, and publishes its current settings back to a retained state topic. One HA automation on a hallway motion sensor blanks the S9+ when the room empties and wakes it when you walk up. It also wakes on the proximity sensor, which on a phone you already have — useful on a small panel where you don’t want to add a separate motion sensor for it.
Both of your phones will run it either way; it needs Android 8.1 or newer.
One unrelated thing worth sorting before you mount them: a phone left on continuous charge will swell its battery eventually. A smart plug that HA cuts around 80% is the low-effort fix, and much cheaper than finding out behind a wall bracket.
A good modern phone will detect when its been on charge for a certain period of time then auto limit the charge to 80%, my samsung phone does this, but yes it’s a good safety install to have a smart plug for battery operated devices to limit the charge when they don’t have the built in limiter.
Yes, I’m using Redmi Pad Pro 12" on my wall with that setting, but I think this feature came with Android 15 at some point. I have it always on on my own Pixel 10 and my wife Pixel 9 as well, saves the battery lifespan 