willcoq
Posts: 3
Joined: Tue Feb 12, 2013 5:22 pm

How to power 7" touchscreen LCD? And USB hub question.

Tue Feb 12, 2013 6:19 pm

My Pi will arrive next week, and I've also ordered a "HDMI+VGA+2AV Driver board+7inch 800*480 AT070TN92 V.5 Lcd with touch panel" from eBay after reading Andrei Istodorescu's blog post here:http://engineering-diy.blogspot.com/201 ... creen.html.

This is what I bought on eBay: http://www.ebay.com/itm/HDMI-VGA-2AV-Dr ... 27ccad6b46

I'm a super beginner at this whole Raspberry Pi thing. I may want to mount the RPi w/ screen in my car or make a portable SNES system out of it. I'm not sure yet, as I have a lot of learning to do.

But first - how do I power the LCD/touch panel? The eBay seller describes the power supply as needing 5~24V. That seems like a pretty large range. Later in the description, he says "Please connected ACC to 12V." Does the touch panel get power by being plugged into an RPi USB port? Can the LCD receive power the same way?

On that note, if I need to plug the touch panel into a USB port, and I will also need RPi USB ports for a bluetooth dongle, wifi dongle, and keyboard, then I will need a powered USB hub. Can this be powered by plugging it into both USB ports like some external hard drives do? Obviously, I want this to be as compact as possible. What do you recommend for a low cost, low profile USB hub?

P.S. I ordered and received a Raspberry Pi enclosure, but I have nothing for the LCD or LCD controller board. What would you recommend for that? I live in Oakland and work in San Francisco, so I have access to places like Noisebridge.net and Techshop.ws, but I'm a complete newb (read: no experience whatsoever) when it comes to 3D printing, creating plastic stuff, and dremeling. I do have limited soldering experience (just enough to know how to do it).

jadonv
Posts: 2
Joined: Sat Dec 01, 2012 3:54 pm

Re: How to power 7" touchscreen LCD? And USB hub question.

Fri Feb 22, 2013 12:06 am

the board that comes with your 7 inch has a power input. so it will not need power from the raspberry pi itself

willcoq
Posts: 3
Joined: Tue Feb 12, 2013 5:22 pm

Re: How to power 7" touchscreen LCD? And USB hub question.

Fri Feb 22, 2013 12:24 am

Thank you. I left a comment on the blog post asking for help as well. I'm pretty sure I know what I need now - mostly. I need a 12v AC adapter with a plug that fits into the power port on the video controller. The only question I have about it now is whether the amps of the AC adapter matter and whether the LCD will work with this battery http://www.amazon.com/Anker%C2%AE-Astro ... 005NGKR54/

bboyandru
Posts: 24
Joined: Thu Feb 14, 2013 7:34 am
Contact: Website Yahoo Messenger

Re: How to power 7" touchscreen LCD? And USB hub question.

Tue Feb 26, 2013 11:16 am

Hi!

I have succeeded in adding touch screen support for eGalax in XBMC 12.
Please take a look:
http://www.engineering-diy.blogspot.ro/ ... lax-7.html

Andrei
http://www.engineering-diy.blogspot.com

girishsan
Posts: 2
Joined: Tue Jun 04, 2013 5:55 pm

Re: How to power 7" touchscreen LCD? And USB hub question.

Mon Jun 10, 2013 7:13 pm

Hi willcoq, Andrei,

Did you figure out the power requirements for the control pannel and display? I have recently acquired "HDMI+VGA+2AV Driver board+7inch 800*480 AT070TN94 Lcd with touch panel". I see that in Andrei's blocg he has used saperate power to led-backlit display. Is that right?. When I geve a test run to the control board + display I found that display screen was flickering (narrow horizontal stripe appearing for fraction of sec every 2-3 seconds). One of my good friend suf=ggesting this may be because of power supply tripping.

Any ideas on:
1> what is the power requirement for the control board AT070TN94 ?
2> what power connectors to be used (does it need power supply on more than one location)?

Cheers,
GT

willcoq
Posts: 3
Joined: Tue Feb 12, 2013 5:22 pm

Re: How to power 7" touchscreen LCD? And USB hub question.

Mon Jun 10, 2013 10:59 pm

girishsan wrote:Hi willcoq, Andrei,

Did you figure out the power requirements for the control pannel and display? I have recently acquired "HDMI+VGA+2AV Driver board+7inch 800*480 AT070TN94 Lcd with touch panel". I see that in Andrei's blocg he has used saperate power to led-backlit display. Is that right?. When I geve a test run to the control board + display I found that display screen was flickering (narrow horizontal stripe appearing for fraction of sec every 2-3 seconds). One of my good friend suf=ggesting this may be because of power supply tripping.

Any ideas on:
1> what is the power requirement for the control board AT070TN94 ?
2> what power connectors to be used (does it need power supply on more than one location)?

Cheers,
GT
Hi Girishsan - I ended up taking the LCD and driver board into Radioshack to see if they knew how I could power it. I spent about $24 on a white AC adapter with a removable connector so you can use it for a number of different port sizes. I also bought the right connector type for the driver board. The screen works fine now! There is probably a cheaper solution though.

I'm not at home right now so I don't know what I bought, but I'll check. As for the touch screen, I can get it to detect input, but I can't get it calibrated properly. I'm in no rush though. I've put this project on hold for a few months in hopes that there will be more Google results on the subject later this year ;)

EDIT: I bought an Enercell 12VDC 500mA AC-to-DC Power Adapter. It came in a green and black box.

fdufnews
Posts: 289
Joined: Fri Oct 07, 2011 5:37 pm

Re: How to power 7" touchscreen LCD? And USB hub question.

Tue Jun 11, 2013 6:32 am

I have made some measurement on this screen. Results are here http://www.raspberrypi.org/phpBB3/viewt ... 62#p366062
As the screen works well with 5V, for my personnal use I power the screen and the Pi from a powered hub with no problem.

girishsan
Posts: 2
Joined: Tue Jun 04, 2013 5:55 pm

Re: How to power 7" touchscreen LCD? And USB hub question.

Tue Jun 11, 2013 3:50 pm

Got it to work,
Manufacturer does not provide much information for this board or the display. One key piece of information provided though was, voltage range from 5-12 is supported. I got 12 V and 2.5 Amp power supply and used only connector 1( black one, bottom left in the image). Power connector 1 and 9 (backlight LED) are interconnected hence did not give separate power for backlight.
Attachments
driver_board.JPG
driver_board.JPG (57.31 KiB) Viewed 14566 times

smuggly
Posts: 112
Joined: Fri Feb 03, 2012 6:09 pm
Contact: Website

Re: How to power 7" touchscreen LCD? And USB hub question.

Sat Oct 05, 2013 4:23 pm

I Just Bought The AT070TN94+Touch Screen Obn Ebay Planing A Car Project With XBMC & OE Or Xbian. I Will Post Back W/ Progress As It Goes.

IntelliTom
Posts: 3
Joined: Tue Nov 05, 2013 10:50 pm

Re: How to power 7" touchscreen LCD? And USB hub question.

Tue Nov 05, 2013 10:53 pm

How are you guys connecting these screens to the Pi? I've been looking at one of these for a while, but concerned about how well they connect up to an RPi? Do you have to go through a VGA converter? Are there driver issues?


alteredHalfling
Posts: 3
Joined: Thu Jan 18, 2018 11:43 am

Re: How to power 7" touchscreen LCD? And USB hub question.

Fri Jan 11, 2019 1:27 pm

I have the sainsmart version of the lcd and controller and would like to make it in to a retropie project but i dont know and having trouble finding out if the lcd controllor will need any mods to run at 5v, i think the lcd will run at 3v-5v-12v from research online

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