tharshan09
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How do I power Car LCD Monitor?

Wed Aug 29, 2012 6:00 pm

Hi everyone,

I have a question related to powering a 7 inch lcd monitor.
I bought this recently, because I thought it would be cheaper than buying a monitor: http://www.amazon.co.uk/gp/product/B005Q6JNV0
it came with yellow cable ( i know where that goes), but to power it it came with 3 wires, red, blue and black. On the manual sheet, one is labelled as ACC, other is DC +12V and other is Ground.

My question is, how do I go about powering this through the sockets on my wall? what adapter will i need to buy to connect the wires?

Joyden few
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Re: How do I power Car LCD Monitor?

Sun Sep 02, 2012 7:08 pm

A question how much cheaper was the screen and what size? Okay well you will need a 12v adaptor. Put the 12v DC into the positive terminal and the earth into the negative. The ACC is to stop you using the screen when the car is off so put that in with the positive. You may need same wiring and soldering experience

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MattHawkinsUK
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Re: How do I power Car LCD Monitor?

Sun Sep 02, 2012 7:36 pm

ACC tells the unit when the ignition is on so as Joyden said just connect that to 12v. All you will need is a DC power supply that can provide 12v and whatever current the screen requires.

Everyone is going to be interested in what screen you've got, how much it cost, where you got it and what the quality is like :)
My Raspberry Pi blog and home of the BerryClip Add-on board : http://www.raspberrypi-spy.co.uk/
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tharshan09
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Re: How do I power Car LCD Monitor?

Sun Sep 02, 2012 8:50 pm

Screen price is 25 pounds and its 7 inch, more details are in the amazon link on my first post. Anyways, a colleague helped me with the soldering and parts. The screen is decent I would say, I just needed something small and cheap so I can test with, I can then take it home and connect it to a TV. Here are some pictures :)
Setup: http://t.co/CY4ojJ9R
Monior: http://t.co/z3mot45S

The monitor works without the ACC connected, I guess it may not be needed after all?

More on the quality of the screen, the text is quite hard to read, for example when the Pi loads. At first I am using the Pi for a media center using raspmc. So when you look at from that perspective the resolution is not a big deal. Once I tinker with the setup a bit more, il let you know if there are any improvements.

recantha
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Re: How do I power Car LCD Monitor?

Sun Sep 02, 2012 9:10 pm

I have almost the exact same problem. I have wires, but I need to run from the mains... should be an interesting experience... or I'll electrocute myself!
My Raspberry Pi blog with all my latest projects and links to articles
http://raspberrypipod.blogspot.com. +++ Current project: PiPodTricorder - lots of sensors, lots of mini-displays, breadboarding, bit of programming.

kenco coffee bean
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Re: How do I power Car LCD Monitor?

Wed Sep 05, 2012 3:05 pm

i have seen this n eBay @ £15

http://www.ebay.co.uk/itm/3-5-Car-Rever ... 20ca96b6e2

* Power Supply: DC 12V
* Visible Area:72 x 53.56
* Power: <=3W

does anyone know if we could mod this so its powered by PI rather than separate power supply - USB provides up to 5v doesn't it? could i do it??? - shows it comes with cable to power - two wires 1 red and 1 black.

and discovered this one below! - can anyone explain this one to me - total beginner here,

http://www.ebay.co.uk/itm/STM32F103RBT6 ... 2a19a75fcf

- as it looks interesting!

recantha
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Re: How do I power Car LCD Monitor?

Wed Sep 05, 2012 3:16 pm

Just dealing with the first half of your last post...
You basically need a 12V mains adapter with the right size jack to power that display.
I have seen someone do a split adapter to power the Pi. Give me a few minutes and I'll find it ;-)
My Raspberry Pi blog with all my latest projects and links to articles
http://raspberrypipod.blogspot.com. +++ Current project: PiPodTricorder - lots of sensors, lots of mini-displays, breadboarding, bit of programming.

recantha
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Re: How do I power Car LCD Monitor?

Wed Sep 05, 2012 3:21 pm

Hmmm. Not quite what I thought I saw, but...
Take a look at:
http://www.skpang.co.uk/blog/archives/541

It deals with a display that takes in 12V but actually regulates that down to 5V, so you bypass it and feed it from a split Pi power supply cable
My Raspberry Pi blog with all my latest projects and links to articles
http://raspberrypipod.blogspot.com. +++ Current project: PiPodTricorder - lots of sensors, lots of mini-displays, breadboarding, bit of programming.

kenco coffee bean
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Re: How do I power Car LCD Monitor?

Wed Sep 05, 2012 3:22 pm

recantha - of course that would be an awesome way of doing it... didn't think about that! it was the power <=3 that threw me thinking its possible to power with 3v or less?! i did see the jack and power 12v dc but just wanted to mull over it with you guys! ]

thanks!

recantha
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Re: How do I power Car LCD Monitor?

Wed Sep 05, 2012 3:27 pm

I would personally LOVE to power a screen off the GPIO pins... that would be sweet... and would save a lot of space. You should see my 7" set-up at the moment. SO MUCH CABLE!!!!!
My Raspberry Pi blog with all my latest projects and links to articles
http://raspberrypipod.blogspot.com. +++ Current project: PiPodTricorder - lots of sensors, lots of mini-displays, breadboarding, bit of programming.

kenco coffee bean
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Re: How do I power Car LCD Monitor?

Wed Sep 05, 2012 3:33 pm

i like it, think that's even the same one i found on ebay!

on the "Modifying the LCD Monitor" that white plug at the top right of the image - think he says he removed the red wire from there and shows it's soldered on to that 2nd cap is that right?!!!

then all we have to do it tap into a 5v power supply - i.e mains charger? or battery pack like him,,, but cant we pull 5v from usb or the GPIO pins?! im happy seriously modding the screen - thinking of removing the housing for the screen anyway as mines all going to be mounted into a picture frame. ( a project people will see when complete!)

thanks for all your help anyway!

Chris

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Montala
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Re: How do I power Car LCD Monitor?

Wed Sep 05, 2012 3:40 pm

tharshan09 wrote: More on the quality of the screen, the text is quite hard to read, for example when the Pi loads. At first I am using the Pi for a media center using raspmc. So when you look at from that perspective the resolution is not a big deal. Once I tinker with the setup a bit more, il let you know if there are any improvements.
Looking at the specification quoted on Amazon, it would appear to be 480x x 234 so I don't know if this is a 'native' resolution you could set in your config.txt file, and whether or not that would actually improve the image , or not.

Others will know more about this sort of thing than me though, I am sure!

recantha
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Re: How do I power Car LCD Monitor?

Wed Sep 05, 2012 3:52 pm

Resolution and clarity on one of those monitors is a pain in the proverbial. I'm struggling getting my 7" screen looking decent... I know it _can_, but...
My Raspberry Pi blog with all my latest projects and links to articles
http://raspberrypipod.blogspot.com. +++ Current project: PiPodTricorder - lots of sensors, lots of mini-displays, breadboarding, bit of programming.

kenco coffee bean
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Re: How do I power Car LCD Monitor?

Wed Sep 05, 2012 3:59 pm

recantha wrote:I would personally LOVE to power a screen off the GPIO pins... that would be sweet... and would save a lot of space. You should see my 7" set-up at the moment. SO MUCH CABLE!!!!!
do you thinks it is possiible to power up off the GPIO pins then?!!! especially with that mod on the 5v line - capacitor?!!!

or has anyone else any input on this haha :D

recantha
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Re: How do I power Car LCD Monitor?

Wed Sep 05, 2012 4:10 pm

Anyone else? Please? GPIO is not something I've messed with so far. (Tho the breadboard is on it's way!)
My Raspberry Pi blog with all my latest projects and links to articles
http://raspberrypipod.blogspot.com. +++ Current project: PiPodTricorder - lots of sensors, lots of mini-displays, breadboarding, bit of programming.

kenco coffee bean
Posts: 20
Joined: Tue Sep 04, 2012 2:53 pm

Re: How do I power Car LCD Monitor?

Wed Sep 05, 2012 5:04 pm

recantha wrote:Anyone else? Please? GPIO is not something I've messed with so far. (Tho the breadboard is on it's way!)
http://elinux.org/RPi_Low-level_peripherals


http://elinux.org/File:GPIOs.png

shows 5v power pin and ground - surely this would work then?!! :?

breadboard ordered and on it way too!!! - wouldn't we just need to hook up to the right pins purely for power?!!

whats everyone else think?!

kenco coffee bean
Posts: 20
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Re: How do I power Car LCD Monitor?

Wed Sep 05, 2012 5:25 pm

Using these soldered to the wire and the other end which is the DC jack to the screen

http://www.ebay.co.uk/itm/100PCS-Dupont ... 3cca647724

That means it connects to GPIO 5V and Negative pins - supplying power - after modding the screen - as per http://www.skpang.co.uk/blog/archives/541

im dying to know if this will work!!!!!

F1p
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Re: How do I power Car LCD Monitor?

Fri Sep 07, 2012 8:57 am

Going a bit off topic here?


I have the exact same monitor:

Image

Red: +12V
Black: 0V
You can see mine is running off my Model Railway's Power supply, conveniently a stable 12V supply.



You need a power supply to reduce the voltage from the mains to 12V DC.
The Pi does not have the power to run the monitor. You will need a PSU.


The cheapest way i can think of is get a 12V wall adapter: http://www.ebay.co.uk/itm/Netgear-AC-DC ... 500wt_1183

Cut the head off the output jack to expose the wires, test with a multi-meter to determine which one is Positive and solider to your screen's cables. Then tape up the connection then power up. £2.50ish.

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MattHawkinsUK
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Re: How do I power Car LCD Monitor?

Fri Sep 07, 2012 9:52 am

Just to clarify, the "<=3" refers to the power in Watts NOT the voltage.

The monitor states 12V <=3W which would suggest a current requirement of 250mA. The Pi can potentially provide this through the GPIO pins but only at 5V.

The only way to power that screen is with 12V. As stated before you could use the same supply to also provide 5V to the Pi.
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Montala
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Re: How do I power Car LCD Monitor?

Fri Sep 07, 2012 10:56 am

@F1p

Looking at the screen image, that actually looks to be quite readable.

Have you added any special lines in your config.txt file to achieve this?

willnue
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Re: How do I power Car LCD Monitor?

Sun Sep 09, 2012 4:53 am

FYI - Sparkfun sells a power supply with both 12v and 5v, which is perfect for using with these screens. The power supply connecter is a standard Molex 4 pin, which you can scavange out of any old PC you have laying around.

Power Supply - 12V/5V (2A)
[url]https://www.sparkfun.com/products/11296[/url]

I also have this same 7" LCD TV screen as well as the 3.5" version ([url]http://www.amazon.com/3-5-Inch-TFT-Moni ... B0045IIZKU[/url]). I can tell you that the readabilty of the 7" is actually worse than the 3.5" and the 7" also has a lot of overscan. As far as the resolution goes I don't belive you can set the actual resolution on composite output, just the type of signal ie.

[code]sdtv_mode=0 Normal NTSC
sdtv_mode=1 Japanese version of NTSC – no pedestal
sdtv_mode=2 Normal PAL
sdtv_mode=3 Brazilian version of PAL – 525/60 rather than 625/50, different subcarrier[/code]

More info: [url]http://elinux.org/RPi_config.txt [/url]

willnue

willnue
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Re: How do I power Car LCD Monitor?

Sun Sep 09, 2012 5:06 am

FYI - Sparkfun sells a power supply with both 12v and 5v, which is perfect for using with these screens. The power supply connecter is a standard Molex 4 pin, which you can scavenge out of any old PC you have laying around.

Power Supply - 12V/5V (2A)
https://www.sparkfun.com/products/11296

I also have this same 7" LCD TV screen as well as the 3.5" version (http://www.amazon.com/3-5-Inch-TFT-Moni ... B0045IIZKU). I can tell you that the readability of the 7" is actually worse than the 3.5" and the 7" also has a lot of overscan. As far as the resolution goes I don't believe you can set the actual resolution on composite output, just the type of signal ie.

Code: Select all

sdtv_mode=0    Normal NTSC
sdtv_mode=1    Japanese version of NTSC – no pedestal
sdtv_mode=2    Normal PAL
sdtv_mode=3    Brazilian version of PAL – 525/60 rather than 625/50, different subcarrier
More info: http://elinux.org/RPi_config.txt

willnue

Krebsy
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Joined: Thu Sep 20, 2012 2:55 pm

Re: How do I power Car LCD Monitor?

Thu Sep 20, 2012 3:38 pm

I do have a potentially spare 5v to 12v dc-dc converter I was going to use to take the 5v power from my 2A Ipad charger to run both the Pi and the in-car screen (or off the "Emergency" mobile battery pack). I think I'll hack the screen though as AndyA suggests and rip out the 12v to 5v regulator instead...

K.

F1p
Posts: 20
Joined: Mon Aug 20, 2012 8:09 am

Re: How do I power Car LCD Monitor?

Thu Sep 27, 2012 6:09 pm

Montala wrote:@F1p

Looking at the screen image, that actually looks to be quite readable.

Have you added any special lines in your config.txt file to achieve this?

No special lines, although the resolution was set correctly in the config.txt file.

the_dude
Posts: 14
Joined: Sun Mar 04, 2012 12:01 am

Re: How do I power Car LCD Monitor?

Fri Sep 28, 2012 9:10 pm

hi, seems like I have been playing with the same screen too...

I decided to see if I could loose a few wires and keep it neater, I put my pi in an old tape backup box - great fit - then cut open the back of the case to fit said case. advantage being it keeps the pi accesable and isolates the base from the back of the screen assembly, plus lets me cut easier access points where I needed them.

Long story short, now have a PiPad - ok, with external keyboard for the mo...but have been eyeing up touch panels recently - screen is powered by 12v adapter - must check out battery packs too - Pi is powered from same supply via a disasembled car usb charger squeezed into the case with power leads going into the GPIO 5v and ground pins. sd card is accessible, as is top usb socked for random stuff (at the mo a wifi dongle.)

will try to post a pic now...wish me luck

[img]/media/xp/Documents%20and%20Settings/Rob%20Cartlidge.DELL-D600-XP/My%20Documents/My%20Pictures/From%20the%20dudes%20phone/Camera%20roll/WP_000023.jpg[/img]

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