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Questions on Matrix Portal Power Hookup ...
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Questions on Matrix Portal Power Hookup ...

by sealyon on Wed Nov 11, 2020 2:13 pm

I have a few questions about how to hookup power my Matrix Portal (#4745). I've reviewed the Learn Guide but I'm still a little confused. I have the 64x32 4mm RGB matrix display and it comes with the power connecter that has the spade connector that connect to the standoffs on the Portal. But where does the Portal power itself get connected? Do you bring external 5V 10A power to the standoffs as well? I'll need enough power for the Matrix and for the Portal. Would be nice if the Learn guide provided a hook-up diagram showing the exact method for providing power for the whole system. Appreciate any help. Thanks.

sealyon
 
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Re: Questions on Matrix Portal Power Hookup ...

by dastels on Wed Nov 11, 2020 2:19 pm

The portal is powered via the USB-C connector.

Dave

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Re: Questions on Matrix Portal Power Hookup ...

by sealyon on Wed Nov 11, 2020 2:49 pm

Well, my project won't have a USB connection in its final form. So, will I have to power this with a USB power adapter? And I obviously need more power to power the matrix, so I wouldn't use the Portal's standoffs and wire the power directly to the spade connectors on the connector for the matrix power? Again, I think this should be discussed in the Learn guide.

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Re: Questions on Matrix Portal Power Hookup ...

by dastels on Wed Nov 11, 2020 3:47 pm

Yes, you could use a USB-C powerbank, or wire an external 5v supply to where the matrix power is connected to.

Dave

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Re: Questions on Matrix Portal Power Hookup ...

by sealyon on Wed Nov 11, 2020 4:13 pm

Ok, I just want to verify. For powering the Portal, I would use a USB-C power adapter, maybe something like the Raspberry Pi power adapter (#4298)? I'm guessing I don't need 3A, what's the min current required? And there's no way to power the Portal from the 5V standoffs? That would be so much easier since you have to power the matrix anyway. And I would have to tie these grounds together, is the standoff GND tied to the logic ground directly? Or do I have to grab the ground from the GND pin on the bottom of the board? Something just seems odd with this or I'm just missing something.

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Re: Questions on Matrix Portal Power Hookup ...

by sealyon on Wed Nov 11, 2020 4:17 pm

And then I would use the power connector included with the RGB matrix but not connect the pins to the standoffs on the Portal. I would connect these directly to my 5V 10A supply for the matrix. And tie the ground on my supply to the Portal. Correct?

sealyon
 
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Re: Questions on Matrix Portal Power Hookup ...

by dastels on Wed Nov 11, 2020 4:30 pm

You could do that. But why not just power from a single supply? If you are going to power the MatrixPortal from the matrix power connectors, you'll want to use a diode (cathode on the portal) to avoid issues when you connect the USB for programming.

Dave

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Re: Questions on Matrix Portal Power Hookup ...

by sealyon on Wed Nov 11, 2020 4:47 pm

Well, the only issue would be finding a USB-C supply that could give me 10A or something close. I want the ability to fully illuminate the matrix if needed. Are you aware of any? And does is wiring on the Portal able to pass that much current from the USB-C connector to the standoff connections?

What type of diode would you recommend?

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Re: Questions on Matrix Portal Power Hookup ...

by dastels on Wed Nov 11, 2020 4:53 pm

Good point about power pass-through. That much would be a problem. A 1N4001 would be more than enough.

Dave

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Re: Questions on Matrix Portal Power Hookup ...

by sealyon on Wed Nov 11, 2020 4:56 pm

Just a note, this is for the same project I've been talking with you about. I was originally going to use the Grand Central to control the matrix but figured it would be easier to use the Portal and I'd also get WiFi capability which I didn't have. I will still keep the Grand Central in, just use it for other control needs. I also will need to use the 4 GPIO pins to add my IR send/receive capabilities to the Portal so it can communicate with the STM32F405 and the Grand Central.

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Re: Questions on Matrix Portal Power Hookup ...

by sealyon on Wed Nov 11, 2020 9:25 pm

If I don't use the standoffs on the Portal for connecting power to the Matrix, which is what I described, then there is no need for diode protection on the power line, right? My thought is I'd connect the spade connectors from the matrix power plug directly to my 5V 10A supply (bypassing the positive standoff). You didn't say whether the negative standoff is connected to the logic ground for the rest of the Portal. If it is, then I would connect my negative 5V supply rail to that so I'd have a common ground but the positive should be isolated without the need for a diode. Correct? And if it's not, then I'd need to use the GND pin on the bottom of the board to get a common ground. Just want to be sure I've got this before I proceed. Thanks.

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Re: Questions on Matrix Portal Power Hookup ...

by dastels on Wed Nov 11, 2020 9:56 pm

- You'd just need a diode on the 5v line to avoid conflicts between 5v sources. You don't need it on ground.

- yes, the negative standoff is connected to the MatrixPortal's ground.

- grounds MUST be connected as all signal levels are relative to ground, so a common ground measn all the circuits have the same idea of what voltages mean (i.e. 5v vs. 3v vs 0v)

- you're understanding seems to be spot-on

Dave

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Re: Questions on Matrix Portal Power Hookup ...

by sealyon on Thu Nov 12, 2020 4:35 pm

Yes, of course, I know the diode would only need to go on the + line.

But, again, I would not be connecting the 5V line to the standoffs, so I don't believe any diode would be needed, since there wouldn't be any shared voltage.

Here are images of how I'm thinking of making this connection. As you can see, the USB connection will be for Portal power only and the Matrix power will go to my 5V 10A power supply. The ground from my external power supply will also go to the GND standoff. But since there is no 5V standoff connection, no diode should be needed. Does this make sense? Thanks.

Matrix 2 - resize.jpg
Matrix 2 - resize.jpg (167.84 KiB) Viewed 319 times

Matrix 1 - resize.jpg
Matrix 1 - resize.jpg (170.17 KiB) Viewed 319 times

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Re: Questions on Matrix Portal Power Hookup ...

by dastels on Thu Nov 12, 2020 4:43 pm

Yes, that all makes sense.

Dave

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Re: Questions on Matrix Portal Power Hookup ...

by sealyon on Thu Nov 12, 2020 4:53 pm

Ok, thanks.

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