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Metro M4 Express compatible with Zumo robot?
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Metro M4 Express compatible with Zumo robot?

by furusato on Fri Oct 09, 2020 6:59 pm

Hi, I've got a Metro M4 Express and was wondering if it is compatible with the Zumo Robot for Arduino - v1.2, which I'm considering purchasing if it is. The M4 Express would be considerably faster than the Uno. Months ago I'd asked (I think here, but maybe directly to Pololu) about compatibility with the Arduino Yun Rev 2, which turns out to have differing power supply requirements, i.e., I'd have to unsolder or otherwise cut the power supply pin. So I'm now thinking of yet another Uno alternative (I know, I'm a lot of trouble).

The two big questions are the form factor and power supply requirements:

    It seems that the M4 Express is the same size as the Arduino Uno.
    Power supply wise, the pins seem to be in the correct place, and the Zumo has a 7.5 volt booster.

This all seems compatible, just wishing for some confirmation from those in the know.

Thanks for any assistance.

furusato
 
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Re: Metro M4 Express compatible with Zumo robot?

by dastels on Fri Oct 09, 2020 8:06 pm

The board size, shape and connections are the same, but the working voltage isn't. The Metro M4 has 3.3v GPIO while the UNO has 5v, which the Zumo will require.

Note on the Zumo product pages it does say
You can use it with genuine Arduino UNO only.


Dave

dastels
 
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Re: Metro M4 Express compatible with Zumo robot?

by furusato on Fri Oct 09, 2020 9:16 pm

Hi Dave,

Here's where my confusion came in, i.e., does the Zumo get its power from the Uno, or the Uno from the Zumo?

The Zumo is an Arduino hat, but since it's advertised as having a "7.5 V boost regulator for powering the Arduino from the Zumo’s 4 AA batteries" I'd interpreted that as meaning that so long as the M4's power requirements were within that range (they are, as its web page states "Power the METRO M4 with 7-9V polarity protected DC") that the boost regulator would be fine as a power supply.

It sounds like it's the same situation as with the Arduino Yun Rev 2, which as the Pololu tech explained to me, I'd have to cut the trace supplying power to the M4 and provide its power from a regulator.

It's all a bit confusing, and a real shame as it seems like it'd be a great processor for the Zumo. They sound so close to being compatible...

In any case, thanks for the clarification.

furusato
 
Posts: 31
Joined: Tue Nov 05, 2019 7:42 pm

Re: Metro M4 Express compatible with Zumo robot?

by dastels on Fri Oct 09, 2020 11:02 pm

From looking at the Zumo schematic, it appears that the Zumo provides ~7.5v to the Arduino (via the Arduino's Vin pin) and gets 5v and 3.3v back.

But power isn't the issue, it's the logic levels.

I agree, an M4 board is a great robot controller.

Dave

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Re: Metro M4 Express compatible with Zumo robot?

by furusato on Sat Oct 10, 2020 1:09 am

Hi Dave,

Ahhh. Thank you. I hadn't cottoned on for some reason to "The Metro M4 has 3.3v GPIO while the UNO has 5v" but now I get it.

I'd kinda thought a long time about the Zumo, but using a 16MHz Arduino on a very limited hardware platform that doesn't support motor encoders is I'm sure fun for its intended purpose, but maybe I'll just focus on making my own robot: a four-micro-metal-gear-motor-with-encoders-mechanum-wheel-robot project that I have almost all the parts for but haven't started yet. For the CPU I'll either use a Pi Zero W, the Arduino Yun Rev 2, or the Metro M4 Express (or maybe experiment with all three!). I've got a pair of 4Tronix PiconZero controllers if I go with the Pi Zero W, just have to figure out four appropriate motor controllers (or two pairs) for the Arduino compatibles...

Thanks much for your help!

furusato
 
Posts: 31
Joined: Tue Nov 05, 2019 7:42 pm

Re: Metro M4 Express compatible with Zumo robot?

by dastels on Sat Oct 10, 2020 2:17 pm

I have a similar project waiting for some 3D design work to be done.

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