stephe
Posts: 4
Joined: Wed Apr 03, 2013 10:38 am

3x 3.5 touchscreen setup with Pi4 and 2 Zeros

Thu May 06, 2021 8:32 am

Hello!

For a new project I need to run a Pi 4 with 2 Pi Zeros, each of the 3 having a standard GPIO-based 3.5 touch screen.
As far as I understood, the Zeros can be powered and ethernet-connected via USB ("gadget"). But will the "master" Pi4 be capable of powering also the displays of the 2 zeros? Provided of course, that enough juice is coming to the Pi4.

If not, how should I distribute power?

imgamingbear
Posts: 14
Joined: Mon Apr 19, 2021 2:59 am
Location: NY

Possible Solution(?)

Fri May 07, 2021 12:31 am

After a bit of research, I don't think you could power both of the Zeros from the 4 since the 4B takes in 5.1V and the Zeros take in 3.3V. I haven't tried this myself but I do have a Pi Zero and a Pi 4 to test this on.

Anyways my suggestions are that if you need it to be portable then you can try a power bank or something with 3 output slots and have each individual cable. If it's going to be plugged into the wall or USB I suggest looking for some sort of USB A or C to 3x USB C cable and use an adapter on 2 of them. (Something like this: https://www.amazon.com/Adapter-Convert- ... 0402&psc=1) And if it's going to be plugged into the wall, use a higher watt adapter or something and that should help if you need it all in one cable.

Hope this helped, bye!
I am literally so uncool that it’s almost as if it were cool.

Well no... not really.

drgeoff
Posts: 11947
Joined: Wed Jan 25, 2012 6:39 pm

Re: Possible Solution(?)

Fri May 07, 2021 7:23 am

imgamingbear wrote:
Fri May 07, 2021 12:31 am
.... the 4B takes in 5.1V and the Zeros take in 3.3V.
Balderdash.
Quis custodiet ipsos custodes?

fruitoftheloom
Posts: 26880
Joined: Tue Mar 25, 2014 12:40 pm
Location: Delightful Dorset

Re: 3x 3.5 touchscreen setup with Pi4 and 2 Zeros

Fri May 07, 2021 7:28 am

stephe wrote:
Thu May 06, 2021 8:32 am
Hello!

For a new project I need to run a Pi 4 with 2 Pi Zeros, each of the 3 having a standard GPIO-based 3.5 touch screen.
As far as I understood, the Zeros can be powered and ethernet-connected via USB ("gadget"). But will the "master" Pi4 be capable of powering also the displays of the 2 zeros? Provided of course, that enough juice is coming to the Pi4.

If not, how should I distribute power?

https://www.raspberrypi.org/documentati ... ower-specs

You have a total of 1200mA, not per port, from USB on the RPi 4B, what is the current draw from the Zero with the Touch Screens attached ??
The information is out there....you just have to let it in.

My other Linux machines: ChromeBox
https://www.aliexpress.com/item/32966393971.html
& Stone Desktop Intel CoreDuo circa 2010

imgamingbear
Posts: 14
Joined: Mon Apr 19, 2021 2:59 am
Location: NY

Re: Possible Solution(?)

Fri May 07, 2021 11:34 am

drgeoff wrote:
Fri May 07, 2021 7:23 am
imgamingbear wrote:
Fri May 07, 2021 12:31 am
.... the 4B takes in 5.1V and the Zeros take in 3.3V.
Balderdash.
I had a quick panic attack so can you please tell me how much each take in combined? Is it more or less? Just curious.
I am literally so uncool that it’s almost as if it were cool.

Well no... not really.

fruitoftheloom
Posts: 26880
Joined: Tue Mar 25, 2014 12:40 pm
Location: Delightful Dorset

Re: Possible Solution(?)

Fri May 07, 2021 11:41 am

imgamingbear wrote:
Fri May 07, 2021 11:34 am
drgeoff wrote:
Fri May 07, 2021 7:23 am
imgamingbear wrote:
Fri May 07, 2021 12:31 am
.... the 4B takes in 5.1V and the Zeros take in 3.3V.
Balderdash.
I had a quick panic attack so can you please tell me how much each take in combined? Is it more or less? Just curious.

The device needs to be powered with a 5V power supply with a USB connector; USB-C for the Raspberry Pi 4, and micro USB for all other models.

https://www.raspberrypi.org/documentati ... ower-specs
The information is out there....you just have to let it in.

My other Linux machines: ChromeBox
https://www.aliexpress.com/item/32966393971.html
& Stone Desktop Intel CoreDuo circa 2010

drgeoff
Posts: 11947
Joined: Wed Jan 25, 2012 6:39 pm

Re: Possible Solution(?)

Fri May 07, 2021 3:44 pm

imgamingbear wrote:
Fri May 07, 2021 11:34 am
drgeoff wrote:
Fri May 07, 2021 7:23 am
imgamingbear wrote:
Fri May 07, 2021 12:31 am
.... the 4B takes in 5.1V and the Zeros take in 3.3V.
Balderdash.
I had a quick panic attack so can you please tell me how much each take in combined? Is it more or less? Just curious.
5.0 volts is the design figure at the USB power input socket (whatever type) on all RPis. PSUs are sometimes nominally 5.1 volts to provide some allowance for voltage drop on the wires between the PSU's voltage sensing point (inside the PSU) and the RPi.
Quis custodiet ipsos custodes?

Return to “Advanced users”