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#1 MrSmoofy

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Posted 16 August 2010 - 07:28 PM

Since I'm new to hardware like this I've been wondering a few things. We will start with the USB connection, I know it powers the board and allows the transfer of data to it for programming purposes but can it be used with say a keyboard, mouse, both, anything use USB? Also is it oneway can only be used as an input or could you connect a usb hub to it? Next is power. What are the different ways to power the board. I know via the USB is one, but I think I saw a power plug as well (does it come with the wall whort?) What about batteries, what kind of battery power are we talking about, or even a switch as well to turn it on and off or a way for it to self power off. Thanks for the help.

#2 Omar (OZ)

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Posted 16 August 2010 - 07:56 PM

Since I'm new to hardware like this I've been wondering a few things.

We will start with the USB connection, I know it powers the board and allows the transfer of data to it for programming purposes but can it be used with say a keyboard, mouse, both, anything use USB? Also is it oneway can only be used as an input or could you connect a usb hub to it?

Next is power. What are the different ways to power the board. I know via the USB is one, but I think I saw a power plug as well (does it come with the wall whort?) What about batteries, what kind of battery power are we talking about, or even a switch as well to turn it on and off or a way for it to self power off.

Thanks for the help.


You can use the Netduino like any other USB device, if you use the serial development firmware. It will turn the Netduino to a custom USB device.

Power:
●input: 7.5 - 12.0 VDC or USB powered
●output: 5 VDC and 3.3 VDC regulated
●analog reference: 2.6 - 3.3 V DC only required when using ADC features
●max current: 8 mA per pin
digital pins 2, 3, 7: 16 mA per pin
analog pins 0-3: 2 mA per pin
microcontroller max current: 200 mA total
●digital i/o are 3.3 V--but 5 V tolerant

There are plenty of things that use these DC wall converters From Airsoft gun battery chargers to variable one like the ones keyboards [piano keyboards] use. Just read the label and make sure the voltage is between 7.5V to 12V AND under 200mA. As far as battery power a 9V battery can do something like this: 9V Battery Clip to Plug
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#3 Chris Walker

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Posted 16 August 2010 - 08:15 PM

There are plenty of things that use these DC wall converters From Airsoft gun battery chargers to variable one like the ones keyboards use. Just read the label and make sure the voltage is between 7.5V to 12V AND under 200mA. As far as battery power a 9V battery can do something like this: 9V Battery Clip to Plug


To follow up on what OZ said, you'll actually want an AC power adapter that provides MORE power than 200mA. I'd recommend 500-700mA. The Netduino will only draw what it needs and what is used via the 3V3/5V/GPIO pins. USB is good for projects which don't require much power, and for really high power apps you'll want to provide separate power to the connected components directly.

As far as USB, the USB port on the Netduino is "USB device." You can make the Netduino into a keyboard/mouse if you'd like, but to plug a keyboard/mouse into the Netduino you'll need "USB host." There are some shields out there which do this, and either we or a community member could write drivers to support USB host shields and various connected USB devices...

Chris

#4 MrSmoofy

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Posted 16 August 2010 - 08:44 PM

Thanks for the feedback guys. Hopefully I'll learn more about the hardware end of things. I'm application developer by trade so writing drivers would be a bit out of my realm but I have all these ideas running around in my head on what the possiblitys are (so far seem endless) on what I might do with something like this. Again thanks for the help.

#5 Omar (OZ)

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Posted 18 August 2010 - 05:10 PM

To follow up on what OZ said, you'll actually want an AC power adapter that provides MORE power than 200mA. I'd recommend 500-700mA. The Netduino will only draw what it needs and what is used via the 3V3/5V/GPIO pins. USB is good for projects which don't require much power, and for really high power apps you'll want to provide separate power to the connected components directly.

As far as USB, the USB port on the Netduino is "USB device." You can make the Netduino into a keyboard/mouse if you'd like, but to plug a keyboard/mouse into the Netduino you'll need "USB host." There are some shields out there which do this, and either we or a community member could write drivers to support USB host shields and various connected USB devices...

Chris


I got a DC Converter that has settings for 7.5, 9, and 12 volts. The current is 600mA, do you think this is save with the netduino? I know you said 500 to 700 mA but is it 100% save?
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#6 Chris Walker

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Posted 18 August 2010 - 05:41 PM

I got a DC Converter that has settings for 7.5, 9, and 12 volts. The current is 600mA, do you think this is save with the netduino? I know you said 500 to 700 mA but is it 100% save?


Yes, it'll perfectly within spec. If you need more power, you can always go a bit bigger.

Chris

#7 CW2

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Posted 18 August 2010 - 06:07 PM

I got a DC Converter that has settings for 7.5, 9, and 12 volts. The current is 600mA, do you think this is save with the netduino? I know you said 500 to 700 mA but is it 100% save?

Yes, it is safe. Netduino on-board regulator has maximum input voltage 20 V. It also has drop-out voltage 1.0-1.1 V, so you need at least ~6 V (7.5 V recommended) on input to get stable voltage for Netduino. You don't need to worry about the power supply current as long as it is higher than minimum value required by Netduino, it draws what it needs. Power supply cannot damage a device by "pushing" higher current, but the device can damage the power supply (if not protected by a fuse) by sucking higher current than it can provide.

Note: For a power supply with variable voltage, the value expressed in W (Watts) or VA (Volt-Ampere) is more useful, because it says what current the power supply can provide at what voltage: Power [W or VA] = Current [A] * Voltage [V]. Thus, if your power supply can provide 600 mA at 12 V, it has power 12*0.6 = 7.2 W, which means it can provide almost 1 Ampere at 7.5 V (7.2 W/7.5 V = 0.96 A).

#8 Omar (OZ)

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Posted 18 August 2010 - 06:45 PM

Yes, it is safe. Netduino on-board regulator has maximum input voltage 20 V. It also has drop-out voltage 1.0-1.1 V, so you need at least ~6 V (7.5 V recommended) on input to get stable voltage for Netduino. You don't need to worry about the power supply current as long as it is higher than minimum value required by Netduino, it draws what it needs. Power supply cannot damage a device by "pushing" higher current, but the device can damage the power supply (if not protected by a fuse) by sucking higher current than it can provide.

Note: For a power supply with variable voltage, the value expressed in W (Watts) or VA (Volt-Ampere) is more useful, because it says what current the power supply can provide at what voltage: Power [W or VA] = Current [A] * Voltage [V]. Thus, if your power supply can provide 600 mA at 12 V, it has power 12*0.6 = 7.2 W, which means it can provide almost 1 Ampere at 7.5 V (7.2 W/7.5 V = 0.96 A).


Ah, very informative! Thank you, I like the middle so I set it to 9V and it works wonderfully!.
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#9 Chris Walker

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Posted 18 August 2010 - 08:25 PM

Yes, it is safe. Netduino on-board regulator has maximum input voltage 20 V.


CW2, thank you for the very thorough explanation. And for noticing our 20V max input on the low-drop-out power regulator (which we officially spec at 12V).

#10 CW2

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Posted 18 August 2010 - 09:04 PM

CW2, thank you for the very thorough explanation.

No problem Posted Image

And for noticing our 20V max input on the low-drop-out power regulator (which we officially spec at 12V).

20 V is absolute maximum rating, could not resist Posted Image

#11 everette

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Posted 11 February 2012 - 02:11 PM

Apologies for bumping an old thread, but I couldn't find a newer thread dealing specifically with Netduino current draw. How did you come by the 200-700 milliamp range? I don't see it listed on the data sheet nor do I see an input wattage from which I could calculate the current based on the voltage. Is that range implicitly defined by the input voltage range for DC voltage?

#12 Chris Walker

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Posted 11 February 2012 - 02:46 PM

Hi everette,

Apologies for bumping an old thread, but I couldn't find a newer thread dealing specifically with Netduino current draw. How did you come by the 200-700 milliamp range? I don't see it listed on the data sheet nor do I see an input wattage from which I could calculate the current based on the voltage. Is that range implicitly defined by the input voltage range for DC voltage?

The power regulators on the Netduino and Netduino Plus are rated for a maximum of 800mA. We don't recommend going that high (energy loss will turn into heat); most users usually stay within ~250mA current draw total.

Chris

#13 Nutz95

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Posted 10 May 2013 - 03:29 PM

Hello, i notices in the Netduino Plus 2 specs that the input voltage is now down to 7.5 - 9.0 VDC

.

I also checked the voltage regulator is a  MC33269DT-5.0G which can handle up to 20v as you mentioned earlier.

So i would like to know if the page http://netduino.com/...plus2/specs.htm is up to date ?

 

why is there a difference between the netduino plus and netduino plus 2 input voltage? is it on purpose?

Can i still plug a 12v power supply on the netduino plus 2?



#14 nakchak

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Posted 10 May 2013 - 04:08 PM

Hello, i notices in the Netduino Plus 2 specs that the input voltage is now down to 7.5 - 9.0 VDC

.

I also checked the voltage regulator is a  MC33269DT-5.0G which can handle up to 20v as you mentioned earlier.

So i would like to know if the page http://netduino.com/...plus2/specs.htm is up to date ?

 

why is there a difference between the netduino plus and netduino plus 2 input voltage? is it on purpose?

Can i still plug a 12v power supply on the netduino plus 2?

 

My understanding is that the change of MCU (from an Atmel to a ST device) required a change in the psu characteristics, and a lower voltage will less stress the regulators etc.  as a stock ND does not have any heatsinks attached to the devices and instead relies upon the PCB to dissipate heat.

 

That said you could probably get away with 12v but you will probably find that the ND runs noticeably hotter than at the recommended voltage and potentially shorten the life of your ND, so i would say stick to powering your ND within the published spec, and if you decide to try a higher voltage you do so at your own risk of magic smoke escaping from the ND

 

Nak.



#15 Nutz95

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Posted 05 June 2013 - 11:33 AM

In that case i just hope Netduino Plus V1 will still be in production and available somehow in the near future.






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