Using Android tablet as RISC OS display

I’m going on holiday to France, and I’d like to have my RISC OS RPi with me for various reasons. Not a problem if there’s a TV with a HDMI input.

But one of my rented locations doesn’t have a TV at all. No bother, because I wouldn’t want to watch French TV, but how can I use my RPi?

I don’t want to take a monitor with me, not even a tiny one which I’d have to buy, but I shall be taking my 10" Android tablet with me anyway. How nice would it be to be able to use that as a display!

After all, I’ll be able to use it over the Internet to see who’s at my front door (Ring doorbell) and to control my central heating, so surely I should be able to see my RPi output?

There should be a gizmo of some sort! Well, apparently, “gamers” and video enthusiasts use something called a “video capture card”, and these devices exist with a HDMI input and a USB output.

Now the micro USB charger input on the tablet doubles as a general USB port, and, for example, USB memory sticks are recognised with a suitable USB to micro-USB adapter cable.

But how, why would a video USB input be recognised by Android? Well, the tablet already has 2 cameras, and if an external USB webcam could be recognised, why shouldn’t one of these devices?

So the generic capability already exists bus-wise.

If it works we’ll find out tomorrow, as I’ve ordered one! A tenner. Cheapest one with next day delivery (Amazon).

Tomorrow is today; I plug it in and nothing happens.

Perhaps the OS only recognises its own cameras. Are there any apps for external USB cameras? There are!

Load-up the first one I find on PlayStore, and the RISC OS desktop appears as if by magic on my tablet screen!

I’m sure many of you already knew that, but equally many will not, so I’m sharing it here.

Out of interest, I have a Logitech K400+ wireless USB keyboard which does work, if a little clumsily, with RISC OS using WinMenu.

;) Killing us all with the suspense.

Load-up the first one I find on PlayStore, and the RISC OS desktop appears as if by magic on my tablet screen!

Sounds like a novel solution, RVnc viewer, would have been my first thought.

What’s the App name? USB-C?

Enjoy your getaway, John. Aaah, the smell of sweet coffee, croissants and wine. ;)

[Updated]

Have to thank John here. It never occurred to me to try plugging a video device into my portable.

I did, installed a USB video app, and now I can see the photo negatives on the screen. Much less bother than using the PC and VLC to do it.

Translating negative to positive just means flipping the curve in Snapseed, but it’s a hassle to do over and over. I’ll probably write some code for RISC OS to load the JPEGs and invert, plus fiddle a little for the inherent colour oddities of 35mm film.

Ironically, the built in camera does not work. ;)

Perhaps the OS only recognises its own cameras.

The reason why I didn’t think of it is because of drivers. I’ve been using Android since v1.2 (or was it 2.1?) and at that time Bluetooth was for headsets. It took ages until keyboard support turned up (and it’s still half-arsed). Also, in the early days simply sending a file between two devices was hit and miss.

My more recent phones support OTG, so some devices can be plugged in. Mouse, yes. Graphics tablet, didn’t want to know.
The portable (which is seriously hindered by using Android without a touch screen!) is the first Android device with actual USB ports. I guess I should have tried plugging things in, but didn’t get any further than my (piano) keyboard (which doesn’t work with my phone!).

Anyway, thanks again for giving me the push to actually try this.

BTW, it is a generic USB video device with a resolution something like 1380×944 at 15fps. Apart from the difference in frame size, it’s pretty much the same generic video class as endoscopes, TV capture devices, etc.

Anybody fancy making a RISC OS driver for these things? ;)

What’s the App name? USB-C?

If it’s not called USB-See, someone missed a chance.

If it works we’ll find out tomorrow, as I’ve ordered one! A tenner. Cheapest one with next day delivery (Amazon).

Pray tell. What is the device? Maybe a link?

Load-up the first one I find on PlayStore, and the RISC OS desktop appears as if by magic on my tablet screen!

Again, what’s the app? Come on, fess up, John?

I did something a few years ago. Amazon Kindle 6 off the top of my head. That does have OTG and usb keyboard and mouse worked perfectly with my hub purchased for the job. So I could use my tablet in a web browser to do some course work on a night shift in between mopping kitchen floor. The missing link was the camera app which I never considered opening. Suppliers could laser cut a laptop case so Android tablet slides out. Usb c provides ability to charge least powerful device so raspberry pi zero? Linux via touch screen and riscos integration without rdp/vnc via mouse and keyboard? Must try and find my kindle, wonder which box that’s in.

Well the app is called “USB camera”, and there are loads of them, so just look at the stars and take pot luck.

The device doesn’t seem to be linkable from the Amazon page, but can be found on Google by searching “digitnow video capture” – last time I looked it was the 2nd picture result. I’ve also seen a similar one at Temu for £4.88 and have ordered a second with a “C” USB output for my newer device(s) at less than £7.

The first experimental one had the advantage of “next day delivery”, but prices can be astronomical, so shop around!

However, this is a first solution – perhaps RDP/VNC could be made to work as Andrew McCarthy suggested earlier, and there may yet be further ideas to come!

EDIT

And I see I wasn’t wrong from the post immediately preceding this! This is probably where I bow out.

Designing laptops is well-above my competence level!

This one is currently £3 with some sort of weird 50% offer that it automatically applied: https://amzn.eu/d/1rigA4F

No guarantees it’ll work though, but it’s the price of an overpriced coffee, so..

I think I was saying albeit not very well John that you essentially seem to have already invented a potential new laptop by getting a screen working in the form of a tablet. It’s your idea I was just saying yeah the bit I did mouse, keyboard etc just worked and combining your idea….I think it’s just a matter of putting the bits together. There will be tablet docks a plenty so laser cutting probably isn’t needed to knock something up. Just like what you’ve already done.

So to explain better, i.e. a usb c on a modern tablet can charge an iphone or the tablet itself from the iphone depending on which has least power in battery? So theoretically you could power a pi zero? The mini hub with display would be interesting to spec up. I did try a ten pound capture card but the ro desktop did not look right. Fantastic idea perfect solution for me and probably others.

This one is currently £3 with some sort of weird 50% offer

I’d give it a try for the price of a coffee, but it’s €16,99 here!

This looks interesting as well, but a bit more expensive. Assuming one can cast to the tablet, the RPi could be by the router and me with my tablet and wireless kbd could be comfy close by unencumbered with any wires!

https://www.temu.com/uk/mirascreen-hd-4k-wireless-same-screen-device-g10-5g-dual-band-projector-hdmi-compatible-dongle-tv-stick-miracast-airplay-g-601099517471755.html

perhaps RDP/VNC could be made to work as Andrew McCarthy suggested earlier

It can indeed. From time to time I use RVNC on my Android phone to check something on my 4té2, thus avoiding to climb two stairs. It even makes RISC OS touch screen aware!

From time to time I use RVNC on my Android phone to check something …

So is that RealVNC, the app you have to register for?

I had a go at that, but gave up.

Yes, that’s RealVNC, and I may have had to register for it, I don’t remember. But it works flawlessly. Your solution however is much more attractive.

Remote Ripple Pro – from the guys that do TightVNC. Small, no registration required.
Works with my PC (uses TightVNC server), haven’t tried it with RISC OS.

Works with RISC OS too. Took me a while to figure out that ‘mouse’ image on screen and that you needed to press it to turn it into a mouse!

Not helped by the fact that I’ve used what is now rVNC for years…

Yes, that’s RealVNC

I’ve now tried this and it works fine, even giving a Menu “key”. It is very comprehensive even giving access to function keys on its keyboard, but I found it a bit slow and over-complicated for my needs (see initial posting).

I used Jeffrey’s RDP server from phlamethrower for the RO side.

Therefore I think I will take a real wireless kbd and mouse – the Logitech K400+ is a bit “clunky” to use for RO – and display using a simpler RDP client for the screen sending, with the reserve option of the video capture to USB device if RDP proves too slow in practice.

The standard wireless kbd & mouse will sit nicely with my tablet display, and using RDP for the display will work wherever the router and RISC OS RPI are situated!

So I think I’m “sorted” for my hols!

This has been a very interesting “journey” for me, and I’m very pleased it has been useful to others as well.

Think kindly of me as you slog away at home!

Interesting – any pictures of the results?

Enjoy your trip – you might be able to exchange some bakebeans for towels :-)

I used Jeffrey’s RDP server from phlamethrower for the RO side.

I think you mean VNC server? An RDP Server would be fantastic, but alas there isn’t one. An updated RDP Client would also be a real boon…

I seem to evangelise about this quite a bit, but I highly recommend Steve Potts’ VNCSvr app to make the server module MUCH more user friendly and add a few additional features.

you might be able to exchange some bakebeans for towels.

😂🤣😂

I think you meant VNC …

Of course I did! So intent on giving the URL …

😂🤣😂

Smiley face? I see:

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