matt@shagshaw.com
Posts: 38
Joined: Thu May 31, 2012 8:04 pm

Powering the Pi and touchscreen

Mon May 13, 2019 2:46 pm

So I have my pi and official touchscreen in the car, running the awesome Crankshaft NG for Android Auto !!!! Check it out, it's ace !!!! getcrankshaft.com

The only issue I am having is powering it, the connection is awkward connecting into the Raspi micro usb connector, and I would prefer to connect on the gpio to power up the pi, but the tpuchscreen also gets its power from there!!!!

So I am really confusing myself here. i can plug the power into either the screen micro usb connection, or the pi, and they both power up......so how ????

It would be ideal if I could provide power to the pi on the GPIO, just confusing myself about how they are both getting power....is the GPIO connections to the screen providing power to the screen ??????? Is the Pi gpio putting out 5v on pin 2 or receiving ????

Matt

aamir24
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Joined: Thu Jan 11, 2018 7:58 pm

Re: Powering the Pi and touchscreen

Mon May 13, 2019 11:33 pm

Try a computer 4 in one USB HUB , plug it on Car charging port. Now you have 4 USB ports. Now Get two micro USB to USB cables and plug those to USB hub. Now you have two micro USB with 5v , plug one in to the screen and 2nd to the Raspberry Pi :)

Andyroo
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Re: Powering the Pi and touchscreen

Mon May 13, 2019 11:46 pm

aamir24 wrote:
Mon May 13, 2019 11:33 pm
Try a computer 4 in one USB HUB , plug it on Car charging port. Now you have 4 USB ports. Now Get two micro USB to USB cables and plug those to USB hub. Now you have two micro USB with 5v , plug one in to the screen and 2nd to the Raspberry Pi :)
No way :lol: bar from a voltage vs current supply issue a lot of car charging ports go on and off as the ignition is turned on and off.

I would take to the folk at https://mausberry-circuits.myshopify.com/
Need Pi spray - these things are breeding in my house...

matt@shagshaw.com
Posts: 38
Joined: Thu May 31, 2012 8:04 pm

Re: Powering the Pi and touchscreen

Tue May 14, 2019 3:15 pm

No, the best connection would be for me to go onto the GPIO, which is currently used by the screen connections.

All I was asking I guess was that can I double connect the power to the GPIO pins 1 & 6 or 2 & 6 to provide power for both the Pi and screen ????????

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Burngate
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Re: Powering the Pi and touchscreen

Tue May 14, 2019 3:56 pm

If that's best for you, then Yes.

Pins 2 or 4 for 5v (note my edit - see Imperf3kt below) and pin 6 for ground can work in either direction - they're just bits of metal - so feeding power into those pins will provide power to both screen and Pi, as long as you can physically mount everything one on top of the other.

There's just one caveat - doing it that way bypasses the protection of the polyfuse.
But on the other hand, for some people it has reduced the possibilty of under-voltage lightning bolts caused by the excessive path-length between PSU and Pi.
Last edited by Burngate on Wed May 15, 2019 8:43 am, edited 1 time in total.

matt@shagshaw.com
Posts: 38
Joined: Thu May 31, 2012 8:04 pm

Re: Powering the Pi and touchscreen

Tue May 14, 2019 7:10 pm

@Burngate Thanks for your help

So pin 2 & 6 are connected to the touchscreen, so I guess I can connect + to pin 1, and use a different ground, either pin 9 or 14 ????

Andyroo
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Re: Powering the Pi and touchscreen

Tue May 14, 2019 7:48 pm

If you have room, you could fit one of these https://shop.pimoroni.com/products/pico-hat-hacker

Just be careful on how much solder you use - if you run it up the pins there is a risk the hat does not sit correctly :lol:

Edit:
matt@shagshaw.com wrote:
Tue May 14, 2019 7:10 pm
@Burngate Thanks for your help

So pin 2 & 6 are connected to the touchscreen, so I guess I can connect + to pin 1, and use a different ground, either pin 9 or 14 ????
All the grounds are connected so any is fine to use
Need Pi spray - these things are breeding in my house...

matt@shagshaw.com
Posts: 38
Joined: Thu May 31, 2012 8:04 pm

Re: Powering the Pi and touchscreen

Tue May 14, 2019 8:47 pm

Excellent.

Thanks to Andyroo and Burngate. Will just modify my USB cable and add the header things so I can plug directly on to the gpio.....

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Imperf3kt
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Re: Powering the Pi and touchscreen

Wed May 15, 2019 12:18 am

Burngate wrote:
Tue May 14, 2019 3:56 pm
If that's best for you, then Yes.

Pins 1 or 2 for 5v and pin 6 for ground can work in either direction -
I think you mean pins 2 and 4. Pin 1 is 3v3 and placing 5v on that will instantly and permanently destroy a Pi.
55:55:44:44:4C
52:4C:52:42:41

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Gavinmc42
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Re: Powering the Pi and touchscreen

Wed May 15, 2019 12:50 am

I have been powering Pi's from the headers since they came out.
Mostly in embedded applications where I design the power supplies too.
Er, GPIO pins stop working if you put 12V on them :oops:
So don't do that :D
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges

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Burngate
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Re: Powering the Pi and touchscreen

Wed May 15, 2019 8:49 am

Imperf3kt wrote:
Wed May 15, 2019 12:18 am
Burngate wrote:
Tue May 14, 2019 3:56 pm
If that's best for you, then Yes.

Pins 1 or 2 for 5v and pin 6 for ground can work in either direction -
I think you mean pins 2 and 4. Pin 1 is 3v3 and placing 5v on that will instantly and permanently destroy a Pi.
Thankyou; I've corrected it, above.

And ... don't put 5v on pin 1 ... using either of 2 or 4, which ever the screen isn't connected to, would be good enough ...
I'm in danger of confusing everything if I keep going, so I'll shut up now.

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Imperf3kt
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Re: Powering the Pi and touchscreen

Wed May 15, 2019 9:45 pm

This may help
Image
The top of the image would be closest to the microSD card slot.
55:55:44:44:4C
52:4C:52:42:41

matt@shagshaw.com
Posts: 38
Joined: Thu May 31, 2012 8:04 pm

Re: Powering the Pi and touchscreen

Wed May 15, 2019 10:07 pm

Ok, making up a lead at work tomorrow to plug into pins 2 and 9, thanks for your excellent help......

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