Raspberry Pi LCD screen compatibility


3 posts
by john_fiction » Wed Apr 18, 2012 2:21 pm
Hi,

I'm planning on buying a Raspberry Pi and powering it off a capacitor, which in turn is connected to multiple solar panels. The reason I'm doing this is obviously for portability. To take portability even a step further I was thinking of buying a small (low wattage) 'raw' LCD panel which has an HDMI input.

My question to you is: are such screens compatible with the Raspberry Pi?

I figured HDMI = HDMI, it shouldn't matter whether you connect the Pi to a desktop screen or a screen which I described above. Please correct me if I'm wrong.

Thanks very much,

John
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by mikezs » Thu Apr 19, 2012 1:44 pm
The R Pi actually has a connector on it to use a small LCD screen (like one from a mobile phone) so you'd be better off using that instead I bet.

No opinion about using capacitors to power the board though, I'd expect a LiPo battery would be much more suited to that though.
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by john_wage » Thu Apr 19, 2012 4:25 pm
Like MikeyB suggests, you'll most certainly need a battery as bridge between the panels and the RPi, most of the time the panels will only prolong the battery life, I don't think the panels alone will supply enough current for display, RPi, + computing, + your connected hardware. Unless you have pretty big panels and during solstace under a clear sky.

There is no reason the HDMI display shouldn't work really, assuming that the RPi has a fully functional HDMI connection (some pins are designated external power rails and in theory they could be left out since they're not being used when you plug in to just a generic HDMI device with it's own PSU).

@What MikeyB said:

The DSI connector on the RPi for LCD modules is still kind of a mystery (no documentation released on it yet to my knowledge at least) and the disadvantage with that, should you get a LCD module with the correct size DSI connector and data interface, in 95% of the cases those modules need 12V LED backlighting, now you will have to build your own DC-DC step-up converter, or buy one.. The HDMI "plug and play" option is already starting to look quite attractive.

Have you found such a monitor that can be used with only HDMI input? It would be nice to share.

Also from a bit of personal experience, if you are going to use a desktop environment you might want to get a big enough monitor, 640x480 would be the absolute minimum usable in my opinion, I've used 800x480 and a lot of desktop applications are not resizeable small enough to fit completely vertically (480 pixels is the let-downer) but it's just about enough.
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