Author Topic: Powering PiCap  (Read 1973 times)

Offline jem5136

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Powering PiCap
« on: January 11, 2018, 09:03:49 AM »
So this is a very basic question, but one that I've had for awhile now. But is it possible to power the PiCap and the Pi with the same power supply powering the lights? This past year I used a micro USB to power the Pi and then added the power from the 12V power supplies (which obviously powered the lights), but I never had a chance to see if I could power everything with just the 12V power supplies. It would save me the hassle of running extra power cables to the enclosures and make a slightly cleaner setup if I could just have 1 plug supplying power for the lights and the Pi/PiCap.

Offline jnealand

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Re: Powering PiCap
« Reply #1 on: January 11, 2018, 09:41:19 AM »
I have two of them running that way.
Jim Nealand
Kennesaw, GA all Falcon controllers, all 12v Master Remote Multisync with Pi and BBB P10 and P5

Offline jem5136

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Re: Powering PiCap
« Reply #2 on: January 12, 2018, 06:17:00 AM »
Awesome! That makes my life so much easier lol I wish I would have known that before setup this past season.

Offline jhoybs

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Re: Powering PiCap
« Reply #3 on: January 12, 2018, 07:53:38 AM »
I actually have one PiCap running on 24V for my floods - there is a voltage regulator in the cap that drives the Pi.
Jim H - Muskego, WI
Falcon F16v3, PiCap, FPPs. Lynx Expresses, xLights

Offline algerdes

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Re: Powering PiCap
« Reply #4 on: January 12, 2018, 12:52:22 PM »
I actually have one PiCap running on 24V for my floods - there is a voltage regulator in the cap that drives the Pi.


Please forgive the side channel information request:
 
@24 volt, is there any heating issues with the regulator.
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Offline jhoybs

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Re: Powering PiCap
« Reply #5 on: January 12, 2018, 02:22:01 PM »
I have not tested heating of the regulator.  The input voltage specs for the PiCap is "5 or 7-24V".

Offline 1983ss454

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Re: Powering PiCap
« Reply #6 on: January 19, 2018, 04:33:08 PM »
I have not tested heating of the regulator.  The input voltage specs for the PiCap is "5 or 7-24V".

I havent seen a manual for the cap, but I have been powering mine with the micro usb, and then powering the lights from the board. How do you setup tells cap to power the pi from the cap?


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Offline AAH

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Re: Powering PiCap
« Reply #7 on: January 19, 2018, 10:00:41 PM »
I actually have one PiCap running on 24V for my floods - there is a voltage regulator in the cap that drives the Pi.


Please forgive the side channel information request:
 
@24 volt, is there any heating issues with the regulator.

It's a switchmode regulator and there will be no heating issue. It's quite likely that it will run cooler at 24V than 12V.

Offline TeaCup

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Re: Powering PiCap
« Reply #8 on: January 21, 2018, 05:59:06 PM »
I discovered this feature by accident. I had 12v connected to the PiCap for the pixels - and when I turned on the 12v power supply, the Pi booted.

I was like ... "that's cool" and never looked back - the 12v power supply I have connected powers the Pi "automatically" as well as the pixels - I did nothing special to make this happen.

Offline jhoybs

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Re: Powering PiCap
« Reply #9 on: January 24, 2018, 08:37:53 AM »
I have not tested heating of the regulator.  The input voltage specs for the PiCap is "5 or 7-24V".

I havent seen a manual for the cap, but I have been powering mine with the micro usb, and then powering the lights from the board. How do you setup tells cap to power the pi from the cap?


Sent from my iPhone using Tapatalk
Looking at the PiCap with the pixel connectors pointing down, the leftmost, topmost jumper controls how the Pi is powered. If the jumper is in place, the PiCap will power the Pi. The 3 jumpers below that one are numbered and control the PiCap's voltage input level.

Sent from my SM-G900V using Tapatalk


Offline TastyHamSandwich

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Re: Powering PiCap
« Reply #10 on: March 05, 2018, 10:33:15 AM »
I, too, discovered this feature by accident. I did the same thing as TeaCup, by plugging in my PiCap first off my 12v power supply and noticed the Pi began booting. I thought to myself "Gee, that potentially solves a lot of engineering problems I might have to face". But the flip side of this is something I need to know as well:

The PiCap will power the Pi via the voltage regulator in it, and apparently another user had no obvious problems with powering the Pi from it's own supply, as well as the PiCap separately. My question is this: If the Pi is receiving independent power from the PiCap, will the PiCap (or can it be jumpered thus) provide power in the event of a power loss event? This is actually something I DON'T want it to do, as I want to run a UPS for the FPP that connects to the GPIO, and has its own power input, which it uses to charge its battery and provide power to the Pi, which it can then monitor and control). If power is not being received through the UPS, it will not serve its function.

IDEALLY, I would have power through the UPS and power through the PiCap, and if power to the FPP is lost, the UPS takes over for a bit until the system gets shut down, UNLESS for some reason the 12v power is still flowing, in which case the PiCap transmits said power to the FPP for continuity. I doubt this scenario would occur often, if at all, so as long as I can get UPS functionality and power the PiCap, I'm happy.

Currently, I'm configuring an FPP with this setup to see what happens, but maybe some of you Falcon gurus can shortcut me an answer. Thanks, guys!

Offline jnealand

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Re: Powering PiCap
« Reply #11 on: March 05, 2018, 03:49:40 PM »
If the power goes off so will your lights, so why bother keeping the Pi running?  There is a work being done right now to minimize the potentail for corruption to the uSD when power goes off.  I believe those changes will be in place before show time comes around this year.  That being said.  I Have been running FPP since the very first version and have never lost a uSD to corruption.  In 2016 I ran 5 Pis in my show, in 2017 I had 10 Pis in my show.  Would seem a lot more cost effective to just have a second uSD ready to go if it is some type of insurance you are seeking.  Just my 2 cents.

Offline bpos

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Re: Powering PiCap
« Reply #12 on: March 07, 2018, 02:14:18 PM »
The only downside to powering from power supply is now there is no way to cut the power going to the pi cap directly. Looks like it back feeds from the data line side back to the Pi. I put a switch on the Power side of the PiCap but it does no good once the data line is connected to power.
I am thinking of adding a diode to the power line on the data side to see if that will limit power back feed.

I don't suppose you need to worry about back feed but I just wanted to add a switch to be able to cut power to the Pi so as to minimize SD corruption? Some times it seems like certain power supplies drain down slowly once disconnected which will drop voltage to Pi while draining.

Just some thoughts..


Offline TastyHamSandwich

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Re: Powering PiCap
« Reply #13 on: March 10, 2018, 03:05:14 PM »
For an update, guys, I got my UPS to function properly. The issue related to v1.8 and prior being based on Wheezy, while the UPS software was only built for and tested on Jessie and beyond.

And you're right, Jim, that if I lost power I'd lose my pixels too. The thing is that I would like to A) Prevent data corruption or potential damage to the Pi by allowing it to always gracefully shut down (I've had multiple issues with this already, even though many people report not), and B) Bridge short power interrupts and allow the show to continue unimpeded. During power loss, playback can be paused or suspended, or even left running if the interrupt is short enough. Once power comes back, the show is back on pretty much immediately, rather than requiring the chance of necessary user input. And nicely enough, C) It gives me a power button on the Pi itself. Hold down the touch sensor, it will boot up or shut down (gracefully).

Now that I've got the device working, I really like the thing. It is highly configurable through the CLI, and it handily exposes many registers to you, and they can be directly modified and set by the CLI, or incorporated into more complex scripts for anyone requiring some real low-level access. I just set my auto_boot_mode and auto_shutdown_timer (not the actual register names) to suit my needs and I'm good to go.

The only downside is that I now have to power it through the UPS, at 5v, rather than letting the Pi draw power from its Falcon PiCap, in order to get any benefit from the UPS software.

Offline jnealand

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Re: Powering PiCap
« Reply #14 on: March 11, 2018, 11:53:23 AM »
Sounds nice, what is the cost?

 

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