small portable display for RPi

Hello to all,
I'm looking for a small portable display which can be used in
combination with almost any RPi (model B/B+/2/3).
Most important: The display should be powered by its own battery (no
external power source except for charging the battery) and it should be
as small as possible. The resolution can be quite low as long as a
standard console font can be read, and the display does not need to
have features like a touchscreen or something like that. The battery
does not have to last for a long time either, one hour would be way
enough. A straight-forward plug'n'play minimal display would be great..
The main purpose will be to plug it in and get the console
displayed (no graphical interface required, just simple shell
environment), mostly on headless Raspberries for troubleshooting issues.
I don't care about HDMI or the composite-AV-Port as long as the
text output can be read.
Does anyone have some hints for me?
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Reply to
Stephan Elinghaus
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find an old netbook or similar and i9nstall a basic linux on it and network in to the pi.
Honestly, it will be cheaper than some kind of tiny hdmi or so on monitor
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Reply to
The Natural Philosopher
Look for things like Car Reversing monitors. You'll need to hook up a 12v battery but most of them seem take composite video in.
Gordon
Reply to
Gordon Henderson
Or without wireless, some PDAs & mobile phones that connect to desktop computers over a USB cable are able to use that computer's network connection.
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Maybe can do same with r-Pi?
The host linux driver is usbnet
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(above is theoretical, I haven't it linux)
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Adrian C
Reply to
Adrian Caspersz
Agreed. The OP is overthinking this. Any decent console app on a smart device or laptop will serve this purpose.
--
If you're not part of the solution, you're part of the precipitate.
Reply to
Jamie Kahn Genet
I will have to disagree. I have been a few decades in the field with such systems (OK, they were physically a lot larger 30 years ago).
In around a third of cases you need good, old console access. The PIs are not the exception here.
For the PI this means a) a serial cable to the serial console b) a USB keyboard/mouse combo and a portable HDMI screen. I use the ones from hardkernel.com (click on displays on the left hand side). I love the old vu8 (discontinued, replaced by vu8c). I also use the small 3.3V console thingies from this site, but I have to crimp new molex connectors on them.
I have a small 12V battery with a 12V/5V regulator for power to the screen. A 6Ah battery lasts nearly two hours.
-- mrr
Reply to
Morten Reistad
Am 2017-02-03 hat The Natural Philosopher geschrieben:
Thanks for your answer, but this won't work for me. All my Pis are running headless. The main purpose for the display is troubleshooting issues. If the pi doesn't even come up the (not working) network access is quite useless then. I think the mentioned car monitor will be the best for me.
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Reply to
Stephan Elinghaus
Am 2017-02-03 hat Stephan Elinghaus geschrieben:
Thanks for all the answers. I think I'll give the car monitor a try, seems to be the best solution for my purposes.
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Reply to
Stephan Elinghaus
Ah. OK.
The same reason we used to have reverse terminal servers on remote serves. To watch the bios and boot messages.
Probably
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Reply to
The Natural Philosopher
A mate has a small battery powered monitor, bought from eBay that has all sorts of inputs that I believe was 'designed' for CCTV field use?
I've used it with him both on CCTV (Composite) and a PC (VGA) and it worked well for both. I *think* it also had an HDMI port.
If it didn't and you can find a battery powered PC (VGA) monitor, I have used an HDMI to VGA dongle with no issue on my RPi's.
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The only requirement is that it has to be powered on *before* you power on (or boot possibly) the Pi but I think that's because it (Linux?) defaults to the CV port otherwise (and may not switch back to the HDMI dynamically). I think you can set it to the HDMI (raspi-config?).
I just use a twin output USB PSU, one uUSB lead straight to the dongle and another uUSB power lead to the Pi has a power switch on it (easier than trying to plug the uUSB connector in poor lighting or access conditions).
Cheers, T i m
Reply to
T i m
Forcing the RPi to use HDMI is done by setting "hdmi_force_hotplug=1" in /boot/config.txt and rebooting. Also see other related HDMI-settings:
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Reply to
A. Dumas
I use the serial port for this. You can get a USB-serial adapter which works with the Pi's 3.3V serial port directly from Adafruit, and it's very cheap. Use it with a laptop/netbook/whatever with a serial port. Can probably even use a smartphone with a terminal app.
--
Andrew Gabriel 
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Reply to
Andrew Gabriel
A laptop/netbook/whatever with a *USB* port: the adapter cable with embedded convertor chip is from GPIO pins on the RPi side to USB plug on the other. So you also need appropriate drivers for this particular serial-USB chip (there are 2 older and 1 current version from Adafruit). And beforehand you need to enable the UART serial function of those GPIO pins, which on the RPi3 requires you to disable bluetooth, I think.
Or if you *do* want to use a serial port on the second device, I guess you need another adapter RS232->USB. I think with phones you may end up in adapter hell: microUSB->RS232->USBfemaleUSBmale
Reply to
A. Dumas
Ah ok. Checking here it was possibly 'Overscan' I was thinking of (that presumably also modifies config.txt).
Cheers.
So, I guess it would make sense to always set the output to HDMI if you never use the composite video output?
Cheers, T i m
Reply to
T i m
Yeah maybe, but I never needed to!
Reply to
A. Dumas
1) If you boot a Pi / Raspbian headless and then plug in a real HDMI TV / Monitor, does it always output video to the HDMI port?
2) When I have tried to retrospectively plug in an HDMI > VGA adaptor I don't think it's detected it and had to reboot to ensure that it did.
Hence why I was wondering if it might be a 'good idea' to make it a default (and am not sure why it isn't in the first place. I mean, now many people use composite video (fir it to be the default)? I know it might be the lowest common denominator etc but ...
Cheers, T i m
Reply to
T i m
[...]
People down-thread suggested small laptop / netbook. If that's the way you want to go a pocketCHIP may be suitable:
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CHIP ($9 computer) + snap on shell with touch screen, keyboard, battery, and some breakout connectors for $69 total.
I'm curious if there is anything off-the-shelf in a similar price range for pi. I have a pi, with one of those Motorola phone docks and I have a pocketCHIP. The phone dock set-up has a beautiful screen and a decent keyboard. The pocketCHIP has a tiny screen and a shitty keyboard. But the phone dock thing is a mess of wires and pocketCHIP is just fun.
Elijah ------ has been considering a second pocketCHIP
Reply to
Eli the Bearded
These are not off-the-shelf products at present.
A closer look at the website's Store page shows that everything except the uncased development kit is out of stock and on back order. The estimated shipping date was January 2017.
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martin@   | Martin Gregorie 
gregorie. | Essex, UK 
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Reply to
Martin Gregorie
I didn't say "pocketCHIP" was "off-the-shelf". I asked "Is there an off-the-shelf pi product like pocketCHIP (in price and function)?"
They have had trouble keeping up with demand. That doesn't mean the product is not available, just that lead time is longer. I've been using mine since September last year as my alarm clock, and I had it in my hands more than a month before I did that.
Elijah ------ but believes Next Thing when they say "Q1 2017" shipping
Reply to
Eli the Bearded
if you put: hdmi_force_hotplug=1 in config.txt then yes.
Bye Jack
Reply to
jack4747

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