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What happened to Aref and 3V3?


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#1 Omar (OZ)

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Posted 10 November 2010 - 11:12 PM

I was looking at the specs page I notice that we are missing Aref and 3V3... Does this mean that it has internal Aref... and how do I provide 3.3V to my sensors if there is no 3V3 pin?

#2 Chris Seto

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Posted 10 November 2010 - 11:20 PM

3.3V will always be present, at least if they want to keep conforming to the Arduino layout. If you didn't have a 3.3V pin, you would need a linear regulator. Basically, this: http://www.sparkfun....products_id=526

#3 Omar (OZ)

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Posted 10 November 2010 - 11:29 PM

3.3V will always be present, at least if they want to keep conforming to the Arduino layout.

If you didn't have a 3.3V pin, you would need a linear regulator. Basically, this: http://www.sparkfun....products_id=526

So if I take the netduino mini's 5V output, and supply that regulator with it... will it drop it to 3.3V? Because I got one of the 5V ones like that, and I have to give it at least 7V for it to output a constant 5V.

Also... if I were to connect that to the netduino should I use anything else along with it as far as safety measures go?

Thanks

#4 Chris Seto

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Posted 11 November 2010 - 01:37 AM

Yes, you can drop 5V to 3.3V with a regulator like that. The only rule is that you need to supply at least around 1.5V more than the output to the input side of the reg to get your desired output voltage. For example, to get 5V you need to supply a minimum of 6.5V.

3.3V + 1.5V = 4.8V < 5V, so you are fine to use that reg to drop 5V to 3.3V.

Also... if I were to connect that to the netduino should I use anything else along with it as far as safety measures go?


...Not really sure what you mean....?

#5 Omar (OZ)

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Posted 11 November 2010 - 02:12 AM

...Not really sure what you mean....?


I think I'm ok now... never mind that.. Thanks for the help :) I'll have to get some of those now.

on an unrelated note I wish you luck with your project, Still waiting for another video ;)

#6 Chris Seto

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Posted 11 November 2010 - 02:23 AM

I have another video already shot, it's just that I keep forgetting to upload it. In the mean time, I am waiting for my 4th GPS in a row. Been very unhappy with the performance of all the modules up to this point.

#7 Omar (OZ)

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Posted 11 November 2010 - 02:54 AM

I have another video already shot, it's just that I keep forgetting to upload it.

In the mean time, I am waiting for my 4th GPS in a row. Been very unhappy with the performance of all the modules up to this point.

Sorry to hear that, good luck with the 4th!

#8 Chris Walker

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Posted 11 November 2010 - 03:48 PM

I was looking at the specs page I notice that we are missing Aref and 3V3... Does this mean that it has internal Aref... and how do I provide 3.3V to my sensors if there is no 3V3 pin?


The Netduino Mini has an internal 3.3V AREF which is fed off of the internal LDO 3.3V power regulator.

To provide 3.3V to your sensors, Chris Seto is correct...you'll want to use a 3.3V linear power regulator (or similar). The LDO (low drop out) versions are especially nice, and you can feed them the 5V power output.

Chris

#9 Chris Seto

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Posted 11 November 2010 - 03:52 PM

The Netduino Mini has an internal 3.3V AREF which is fed off of the internal LDO 3.3V power regulator.

To provide 3.3V to your sensors, Chris Seto is correct...you'll want to use a 3.3V linear power regulator (or similar). The LDO (low drop out) versions are especially nice, and you can feed them the 5V power output.

Chris

According to the datasheet I read before I posted, that is an LDO reg I linked. Then again, Sparkfun apparently has two products (not LDO, LDO) under the same part number, so who knows. :)

#10 MattW

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Posted 11 November 2010 - 09:49 PM

I have another video already shot, it's just that I keep forgetting to upload it.

In the mean time, I am waiting for my 4th GPS in a row. Been very unhappy with the performance of all the modules up to this point.

Let us know which one you settle with - I'l be very interested to know.

Thanks and Cheers,
Matt.

#11 yandreev3

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Posted 30 January 2012 - 12:53 AM

Hello Everybody!

I decided to go poking around my Netduino Mini with my multimeter (Which could explain why I continually have to replace netduinos and arduinos) and found not only 3.3v but .8v as well on the netduino mini. If you decide to tap into these voltages make it so only if you cant possibly buy a voltage regulator. I should also add that i am using a $300 soldering station and a very precise multimeter, so don't try to do this if you have one of these soldering irons that have a tip bigger than my finger because you will kill your netduino. I have pointed out the locations of these voltages on a picture that can be viewed on the following link because it was too big to be attached. link: http://i1148.photobu...v3/IMG_7158.jpg

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