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#21 Websteria

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Posted 10 September 2010 - 04:04 PM

Interesting read - thanks...

My initial thought was "Cool, something I can write simple C# in".
I have a Netduino and am busy rebuilding a balance 'bot with it (currently runs on Arduino)

Overall I think it's a cool piece of kit with the biggest bonuses being the IDE used.

I would say, the biggest downer I have with the Netduino is the low sink / source capability of the pins. 8mA per pin IIRC. For all things digital, that's fine but I've used them for other things like the simple LED and using digital pins to power sensors (I can turn them on and off that way).
Oh, and it locked up on me the first day I had it. (Don't think it was my fault) but did the age old MS fix: Have you rebooted yet?

Some things that would make it great(er): (I know they will come with time)
- A "mega" but the inner pins have the same layout as the standard one. This will allow me to use normal shields but still have a mega
- Higher current capacity on the pins.
- Smaller boards. (My balance 'bot could do with less board and more battery ;) )

Other than that, I do like. :)

Oh, and "threading" ability is the best. I can [some would say be lazy and] just do things in different threads.

Cheers,
Crispin


My solution to that has been to use an NPN transistor and allow the "low source" signal to act as the switch to open the power to the higher voltage device. I used this (minus a netduino but same idea) to make a buzzer buzz (which requires 1.5-3v) when triggered by a motion sensor (enough output to light an LED, but not to buzz).

Jeff

#22 Crispin

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Posted 10 September 2010 - 07:28 PM

Well, most of the questions have been answered then. It's by no means a deal breaker. It just means that you have to do things differently. Using a transistor or Darlington array to do the switching will work just fine, as mentioned. @Websteria - Neither platform will allow a buzzer to buzz. They are microprocessors and as such, pretty low current devices. Anything more than an LED and you should use something else to switch it. What I was talking about is driving sensors off digital pins. This allowed me to turn them on and off when I wanted which saves battery. Still doable now but I need an extra component. Like I said, not a biggie. ;) As an aside, if you do use something like a buzzer, please please please use a diode across it to stop any back EMF.
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#23 Websteria

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Posted 10 September 2010 - 07:50 PM

Well, most of the questions have been answered then.

It's by no means a deal breaker. It just means that you have to do things differently. Using a transistor or Darlington array to do the switching will work just fine, as mentioned.

@Websteria -
Neither platform will allow a buzzer to buzz. They are microprocessors and as such, pretty low current devices. Anything more than an LED and you should use something else to switch it.

What I was talking about is driving sensors off digital pins. This allowed me to turn them on and off when I wanted which saves battery. Still doable now but I need an extra component. Like I said, not a biggie. ;)

As an aside, if you do use something like a buzzer, please please please use a diode across it to stop any back EMF.


Even with something as low voltage as 1.5/3v? It seems the transistor should be able to stave off the EMF, if it were a relay then yes a diode is necessary... :-) Maybe I'm wrong.




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