Driving Multiple LCD displays Using Android Tablet

SteelTherapy

Member
Oct 12, 2011
4
0
I want to drive three separate 7" color LCD displays using an Android Tablet. The displays will be simple but dynamic. My intention is to use them to replace the instrument cluster on a vehicle. The android tablet will receive the vehicle sensor information (speed, rpm, temp, etc) via a USB Analog to Digital Converter. I'm not too concerned about writing this portion of the app for the vehicle. The part that I have no idea about is how to drive the multiple displays. Can an HDMI output be split by addressing it using a type of addressing? Can the LCD displays be driven as a USB device using a USB hub?

Any suggestions?
 

SteelTherapy

Member
Oct 12, 2011
4
0
Ok, how about a different way. How about using 3 Android Tablets as slave displays for a single master Tablet. Communications through Wi-fi or bluetooth?
 

skoster

Member
Apr 1, 2011
44
9
Probably find more info in a carputer forum.

I do wonder, however, why you want an android tablet to drive this all, why you want the tablets to interface if they'll each show different instruments, and why you think android is the route to get where you're going.

Personally I'd probably buy/build a little linux box and use that to drive the displays if I really thought I needed the full on computer experience. That way I'd have a robust, well developed OS which has in place everything I need. I would expect it to cost about half as much and I'd know that the components I specified were rated for the duty (have you ever felt behind the dash of a running car? it's VERY hot, dusty and vibrating).

However, I'd probably skip the full computer thing altogether and use PICs and display drivers for less than 1/10 of the price and a huge increase in reliability.
 

SteelTherapy

Member
Oct 12, 2011
4
0
Very good questions. Thank you for your input. To answer a little bit. I want to be able to use the android tablet to control what information shows up on the 3 LCD displays. It may not always be gauges. If I was using the tablet as a GPS I would want to display the map/directions on one of the 3 displays. I have other functions that would take place of the various instruments as selected by the "master" tablet that would be mounted in a central console. The android touch screen makes for a nice interface to start thing off.
 

skoster

Member
Apr 1, 2011
44
9
Well, I wasn't able to find an API for it, so you'd probably have to hack the functionality. Perhaps write a program which sends info out to a microcontroller which cycles through the monitors and connects the HDMI port to the monitor it needs to go to just before data is written out to it, then goes to the next one. You'll probably need to either live with a lot of flickering or run a high refresh rate since it will be divided between four monitors. In any case you'd need something with a LOT of video memory.

Honestly, it would be HUGELY easier to just use an appropriate OS which already has truly robust solutions for this, and write a custom overlay for it. But don't let me dissuade you, it would be really cool if you got it to work your way.
 
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