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Mikumiku747
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Joined: Fri Nov 01, 2013 10:54 am
Location: Sydney Australia

Portable R-Pi: Powering a screen

Fri Nov 01, 2013 11:09 am

Hi, I'm thinking of purchasing a 4.3" TFT off of adafruit and I was wondering iv I could power it using the 5V and Ground GPIO pins. also, I was thinking of including a small extension port for the HDMI lead, in case I want to use it with my portable pi. Will using a HDMI extension cable make the Pi think that HDMI is plugged in, rendering composite useless, or is this just a thought of mine. Included is a picture of my planned case in MS paint to help understand. Please keep in mind that suggestions should be budget friendly, and the entire thing should be self sufficient, apart from occasional charging. The power supply is a 5V 4A battery that powers the micro B port on the pi.

Diagram of the case:
case diagram.png
The diagram of the case
case diagram.png (12.27 KiB) Viewed 2739 times

texy
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Re: Portable R-Pi: Powering a screen

Fri Nov 01, 2013 11:31 am

Hi,
depends on the power requirements of the TFT, but probably it will be no problem to power it. Is the screen hdmi or composite?
I,m not sure why you need to 'fool' the pi into thinking it has an hmdi device connected, but just fitting a cable wont do it.

Rgds,
Texy
Various male/female 40- and 26-way GPIO header for sale here ( IDEAL FOR YOUR PiZero ):
https://www.raspberrypi.org/forums/viewtopic.php?f=93&t=147682#p971555

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misho.petrov
Posts: 48
Joined: Mon Oct 21, 2013 8:52 pm

Re: Portable R-Pi: Powering a screen

Fri Nov 01, 2013 1:05 pm

I have just added a 4,3" display to the upper side of my case (I'll post a picture soon) and I'm draining the power directly after the SW1, so the display will be powered only if the Pi is switched on.
1. RPi B 512 MB + Sandisk 2GB c4, vesa mount;
2. RPi B 512 MB + Hama 16GB c10, heat sinks, micro fan, built-in lead-acid battery, duplicated factory plugs, 4,3" TFT, usb mini wireless keyboard, TDA2822 and speakers;
3. RPi 2 + Maxell 16GB c10.

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Mikumiku747
Posts: 17
Joined: Fri Nov 01, 2013 10:54 am
Location: Sydney Australia

Re: Portable R-Pi: Powering a screen

Sat Nov 02, 2013 5:04 am

texy wrote:Hi,
depends on the power requirements of the TFT, but probably it will be no problem to power it. Is the screen hdmi or composite?
I,m not sure why you need to 'fool' the pi into thinking it has an hmdi device connected, but just fitting a cable wont do it.

Rgds,
Texy
Thanks Texy :)
The screen is composite, and I just wanted to make sure it ISN'T fooled into thinking HDMI is plugged in. Thanks for the response, You've answered all of the questions I was asking. :D

Thanks for the reply,
Mikumiku747
Thanks,
Mikumiku747 :)


Have a look at my portable pi:
http://www.raspberrypi.org/phpBB3/viewtopic.php?f=40&t=59903&p=447601#p447601

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Mikumiku747
Posts: 17
Joined: Fri Nov 01, 2013 10:54 am
Location: Sydney Australia

Re: Portable R-Pi: Powering a screen

Sat Nov 02, 2013 5:10 am

misho.petrov wrote:I have just added a 4,3" display to the upper side of my case (I'll post a picture soon) and I'm draining the power directly after the SW1, so the display will be powered only if the Pi is switched on.
Hi petrov,
Thanks for the response, your case is similar to what I am trying to make, except mine is waaay bulkier :(, but hopefully its still as cool as yours :). Mine will be powered off of the 5V GPIO pin on the Pi, but Texy told me it works. Yours looks awesome, Can't wait to see it with a screen. I'm getting the one from adafruit, along with almost all the rest of my parts.

Thanks for the reply,
Mikumiku747

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