morphious6
Posts: 17
Joined: Thu Sep 17, 2015 8:21 pm

Power display from Pi 2 ?

Fri Sep 18, 2015 11:59 pm

Hello, I have a shield on my Pi 2 that supplies power to the Pi 2. Is there I way that I can use power from the Pi 2 to power the display so I will not have to have a separate power supply? I've tried USB out from Pi 2 to the power in on the display board with no results.

The power coming into the top level shield is 24V 3A, and most of that us used to power 5V via RJ45 too 3 motors. So there should be enough power available to power the display as well.

Any ideas would be highly appreciated.

-D

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DougieLawson
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Re: Power display from Pi 2 ?

Sat Sep 19, 2015 7:20 am

If the pi is powered with a beefy supply then you can use one of the four USB sockets to power any peripheral device.
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morphious6
Posts: 17
Joined: Thu Sep 17, 2015 8:21 pm

Re: Power display from Pi 2 ?

Tue Sep 22, 2015 12:07 am

Hello I tried to use the USB, but could not get it to power up from any USB port. Is there a way to chekc in the OS that power is on to the port? I am using DietPi OS. Could that be off by default?

skpang
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Location: Essex, UK
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Re: Power display from Pi 2 ?

Tue Sep 22, 2015 10:51 am

I've also tried to power the display from the Pi and also couldn't get it to work. I think the reason is that there is a power up delay on the USB port on the Pi. By the time the USB port is powered up the Pi has already tried to initialise display but it is not ready. You almost like to need to power up the display first.

BMS Doug
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Re: Power display from Pi 2 ?

Tue Sep 22, 2015 11:13 am

A potential method would be to use the GPIO Jumpers (scroll down to powering the display #3).

Your top board may not leave any GPIO exposed, if there is anywhere that gives you an output 5V you should be able to connect it to the Jumper pins of the display board.

If that doesn't work then solder a micro-USB connector onto the ends of the 5V output cable and connect that to the displays 5V input.
Doug.
Building Management Systems Engineer.

morphious6
Posts: 17
Joined: Thu Sep 17, 2015 8:21 pm

Re: Power display from Pi 2 ?

Thu Sep 24, 2015 12:39 pm

Powering the screen from the 3rd party Hat board that has 5v power to the displays daughter board worked perfect. Thank you for your help!

BMS Doug
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Re: Power display from Pi 2 ?

Thu Sep 24, 2015 12:43 pm

morphious6 wrote:Powering the screen from the 3rd party Hat board that has 5v power to the displays daughter board worked perfect. Thank you for your help!
I'm glad to have been of assistance.
Doug.
Building Management Systems Engineer.

gadgetoid
Posts: 152
Joined: Wed Mar 07, 2012 9:58 pm

Re: Power display from Pi 2 ?

Thu Sep 24, 2015 12:59 pm

Just a quick note to say I tried a similar set up- powering the display from the Pi- and found that it would not work. I'm pretty sure any setup where the display isn't powered up before ( or at the same instant as ) the Pi will not work due to whatever display initialization sequence there is at boot.

morphious6
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Re: Power display from Pi 2 ?

Thu Sep 24, 2015 8:37 pm

That makes sense. I just checked and the 5V is immediately available. Mine is being powered by an always on 5v source from a board on top of the Pi 2.

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