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MicroBlocks

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Joined: 12/05/2012
Location: Thailand
Posts: 2209

Posted: 02:46am 21 Jun 2013

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I am finishing my version of a CMM clone and want to request experiences with the original Color Maximite.
I would like to replace the diodes and jumper/switch that protect parts of the circuit depending if it is powered through an external power supply or by a usb connection.
The reason is that a diode will have a voltage drop that can cause the 5v line to be lower then expected.
Was the voltage drop a problem in your experiments or projects?
Did you ever had problems using it while powered through the USB or when using the external power?
Is the amperage enough to power other circuitry that you connect to it.

Would like like to see this part of the (color maximite) improved?
Like more amperage, short circuit protection or maybe other voltages?

Would being able to power from a Li-ion or other type of battery pack be of interest?

Is separating the power supply from the rest of the circuit a better solution?
You would then have a 5v,3.3v and gnd connecter to a power supply of your choice.

Any other suggestion?

Microblocks. Build with logic.

djuqa

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Joined: 23/11/2011
Location: Australia
Posts: 447

Posted: 11:43am 21 Jun 2013

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Download the schematics of the duinomite standard or mega and see how olimex does it.
their P/s section is brilliant.
Ability to power unit from usb/external power/LIPO batterry

VK4MU MicroController Units

Grogster

Admin Group

Joined: 31/12/2012
Location: New Zealand
Posts: 9308

Posted: 01:43pm 21 Jun 2013

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If you are using a standard diode, voltage drop is 0.6v, but if you use a power Schottky diode, the voltage drop is only 0.1v - that may well be a simple option, depending on what you already have. If on the 5v rail, a Schottky will only drop the voltage to 4.9v, which is well within spec.

Smoke makes things work. When the smoke gets out, it stops!

panky

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Joined: 02/10/2012
Location: Australia
Posts: 1101

Posted: 01:44pm 21 Jun 2013

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TZ, I have a CGCMM1 and have used it extensively with power from the usb without any problems. I also have a Duinomite Mega and echo djuqas comment.
My own preference would be for a wide range single voltage, ac or dc with all necessary voltages plus options like rechargeable lipo on board. I realise that this is also the most expensive option and possibly overkill for many projects so maybe a minimal power solution on board with an optional full servive off board module?

Cheers, Doug.

PS. Can't wait for your CMM - will purchase one when available. . D.

... almost all of the Maximites, the MicromMites, the MM Extremes, the ArmMites, the PicoMite and loving it!

bigmik

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Joined: 20/06/2011
Location: Australia
Posts: 2914

Posted: 02:25pm 21 Jun 2013

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Hi TZ,

I also dont like the Diodes in series with the 5V supply and I have had some issues with drive capability running a MM off USB power. I prefer link or mini switch options myself.

If I run off USB I have a short (30cm) USB lead that is quite thick and that seems to always work ok...

Regards,

Mick

Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<<

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