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Mario Vernari

Member Since 22 Jan 2011
Offline Last Active May 05 2017 11:55 AM
*****

#61931 Controlling Multiple I2C devices

Posted by Mario Vernari on 23 March 2015 - 08:05 AM

Tim, I'm 100% with you, but abstraction comes at a cost and Micro Framework tries to solve high-level problems on (relatively) very poor hardware.

Swapping the config is surely cheap in term of computation, but of course leaks in term of abstraction. However, you might think the I2Device as the "I2C logic driver", and the various configs as "instances" of this driver. Such a viewpoint comes maybe a little closer to the abstract-hardware model.

Good luck!




#61910 External switch

Posted by Mario Vernari on 20 March 2015 - 04:53 AM

I just tried for you...

 

explosion-of-fire.jpg

 

 

In theory, your circuit should work, but the problem is that the Netduino does not offer a "pull down" feature.

Simply invert the logic, and wire the button from the input to the ground, then set the "pull up". This is also the preferred way to connect a pushbutton/switch because the ground is everywhere but the +3.3V not.

 

Remember, if you try to register the button activity via interrupt or so, you may easily experience "bounces". That is, when you press the button, you'll see several unexpected "on/off" events, which are undesired. Those bounces are due to the mechanical structure of the button.

There are two ways to solve this problem:

  • add an external capacitor (e.g. 100nF or more, not critical) across the button. This is an "hardware filter".
  • do NOT use the interrupt, and implement a "digital filter" by sampling the state of the input periodically, then detect the stable state. In this case you won't need a capacitor.

Bear in mind, for a quick test on a breadboard, there's no problems at all. Once you'd create a reliable definitive circuit, I'd use both the filter ways: capacitor and sampling. Bullet-proof!

 

Good luck!




#61449 raspberry pi 2

Posted by Mario Vernari on 02 February 2015 - 01:22 PM

...just forget...

MF does have sense...if MS will *SERIOUSLY* develop it...otherwise I totally agree that PI or whatever else board will replace it.




#61448 raspberry pi 2

Posted by Mario Vernari on 02 February 2015 - 01:11 PM

RPi is a proven device, also available in an embedded format (compute board).  They probably sold more today in 11 seconds than all others combined forever. It's barely second all time to Arduino, which IS a prototype platform like the Netduino.   If the hype to open source .Net to linux et al ever happens, it's just 1 more thing on a successful product regardless, but certainly not a dependency.

 

They sold thousands of boards for true, but the quantity does not make the hardware more reliable over another one.

Again, the board ships with *no* flash, so you must connect a SD. Would you rely on a SD connector durability (dust, oxidation, etc) along 1+ years in a normal city climate?

Have a look at some comparisons between the PI1 and the BBB:

http://makezine.com/...aglebone-black/

 

I can flash an app to a Netduino/Arduino and forget it for years (possibly avoiding the pins connection as well).

 

 

When you can get a PI for $35.00 why would you spend $60.00 on a Netduino 3. Especially since Windows 10 is going to run on Pi 2.

 

https://dev.windows....Program-for-IoT

 

Again, I'd wait for "singing in the rain" until some concrete signals are coming...

I've heard the Galileo and the Edison support, but nothing concrete. There's also a Compact porting for the BBB, but without much support.

 

By the way, the current Netduino and a "bigger bro" will have several differences, that you can't wipe off with a bunch of bucks less.

Here are some:

  • power consumption
  • power-up time
  • hardware support (I mean *how* to write your own driver, *how* to port your own board, etc)
  • NVRAM support
  • software stability (I mean porting support)
  • actual processing speed (the MF is way lighter and OS-less than a regular Windows)
  • licensing price?...this is unclear.

Somebody says it's free, but WEC 2013 is also "free" unless you use for commercial applications (i.e. not hobby/prototyping)...

 

I want to see some real-life app, both headless and UI, then I'll decide whether that's a good news or not.




#61435 Things we can learn from GHI

Posted by Mario Vernari on 02 February 2015 - 07:04 AM

I'm not going to lie, GHI has a much better community. Why?

  1. Trained experts supporting new comers VERY well.
  2. A very reliable Gadgeteer production.
  3. Many members can show their custom made parts.
  4. Their "Codeshare" is a brillient place for Drivers.
  5. Though not as open source, good structure and gameplan.

I hope we can all learn from this.

 

What should we learn?

It seems to me that, especially on the "hot" Netduino era, this forum was plenty of enthusiast people. Also many of them were experiencing the Netduino forum as a "big family", full of warmful users.

 

Gadgeteer, in my mind, is a flop. Nothing more than a flop.

My philosophy endorses the KISS principle: http://en.wikipedia..../KISS_principle

The Arduino board boomed because its simplicity, as the same was for Netduino...

 

Many projects created on Netduino are still alive and used even on other platforms: why do you say the users "didn't show their parts"?

If you mean about hardware, I may agree, but it's not because the forum, but because the users. Honestly speaking I often see users refusing to learn a bit of electronics...what else?

 

The problem isn't Netduino, but MS which almost dropped the MF project. That's a big blame, at least in my opinion.




#61397 Microsoft Azure IoT Contest

Posted by Mario Vernari on 28 January 2015 - 04:55 AM

Create a Microsoft Azure application that unlocks the true power behind embedded and connected devices: the web services and applications that actually connect those devices.

Sponsored By
MicrosoftLogo_60x74_.jpg

You could use Azure and the CodeProject API to create a mobile web app to keep track of your CodeProject rep points from your phone, or build a webservice that allows a LED on your Netduino board to blink when you get a new message. What about constructing an IoT-powered robotautomating your home or creating a dashboard that connects to your Fitbit to track your fitness? The sky's the limit - suprise and impress us!

Submit an article outlining how you built your Azure IoT app (with code snippets and screenshots) and complete tasks and missions for your chance at loads of cash prizes.

 

Read here:

http://www.codeproje...oT-Contest.aspx

 

Good luck to everyone!

 

Please Chris, make this post as sticky.

 




#60666 Azure Veneziano

Posted by Mario Vernari on 09 November 2014 - 08:05 AM

After a long silence due to business tasks, here begins the story of "Azure Veneziano": a hobby/tutorial telemetry control Azure-based, and using a Netduino Plus 2.

 

Enjoy the part #1...

http://highfieldtale...neziano-part-1/

 

Here is the part #2...

http://highfieldtale...neziano-part-2/

 

...then part #3...

https://highfieldtal...neziano-part-3/

 

...then the same as part #1, but using the Seeedstudio LinkIt ONE board (awesome, but still love Netduino)

https://highfieldtal...ano-linkit-one/




#58488 Netduino and FTDI EVE Board

Posted by Mario Vernari on 31 May 2014 - 10:27 AM

Finally, the repository is up.

https://cetmicrowpf.codeplex.com/

Have fun!




#58061 how to set external REF voltage for ADC & REF voltage min and max values

Posted by Mario Vernari on 12 May 2014 - 03:36 AM

Mario, thank you very much for your reply. But, I will not use Netduino for ADC reading. 

 

Instead of using op-amp (which means a lot of noise or a lot sampling for me & I need 3 opamps, because I need 3 different readings) I'm planning to use x3 ADS7822 with 400mV vref supplied by LT6650. I'll have 400mV/4096 resolution and noise reduction with relatively less cost. 

 

ciao from Trieste!

 

many thanks, 

Mirac

 

That's a good decision!

 

Trieste? Will you join the incoming mini-Maker Faire, next Saturday?

http://www.makerfair...t/index_en.html

I believe to be there on the afternoon!

Ciao




#57747 Capacitive Touch Sensing

Posted by Mario Vernari on 25 April 2014 - 04:06 AM

Martin, the idea is really valuable, but I'd warn about the hardware section before someone damage its board.

Touching an open (i.e. floating) pin is one of the easiest way to burn the input stage, because even a weak electrostatic charge can be disruptive.

 

I see you're in Germany, so I believe there is not so much different than here in Italy. When I wear rubber shoes and some wool short, I notice that my body charges a lot of electrostatic energy, then often it's discharged toward some grounded shield. When I see a 1cm-spark it means that's a roughly 2000V-spark!

 

My suggestion is to add an high value resistor in series to the pin. Try with 1Meg or even higher.

Also, more important, a couple of diodes (e.g. 1N4148) from the pin to the ground and +3.3V, respectively. Their aim is to short any too-high or too-low voltage to the positive and negative rail, respectively.

 

Again, it's NOT a critic to your project! It's just to avoid some dirty effect and a Netduino (or Arduino) to throw away.

Good luck!




#57190 What current does a netduino plus 2 use?

Posted by Mario Vernari on 28 March 2014 - 05:11 PM

I own a Netduino Plus 2 and I can sure you that a 300mA PSU is far enough for the board itself. Consider that when you plug the board via USB, the current can't be more than 500mA.

That's for the board itself, though. If you need some other device to power with the same PSU, it depends on what's the total load.

Have fun!




#57161 Modbus-TCP library

Posted by Mario Vernari on 27 March 2014 - 04:24 AM

I neet to setup Modbus TCP beetween some Netduino 2 Plus boards for a Project and so i found an downloaded this library. My Problem is that i couldnt find any Examples how to include this Library to my programm and i am pretty new at working with Visual C#.

 

Has anyone an Example or link for me?

 

Thank you very much!

 

Hello.

If you have no-at-all or even few experience with C# and Netduino, I'd suggest to begin with something easier. The library is not particularly complex, but it assumes that the developer *knows* how to deal with the framework, the language and the hardware.

Also consider to take practice just without the Netduino first. Try to create some small programs for PC with the Visual Studio Express.

http://www.visualstu...udio-express-vs

 

The repository does include several examples. If you need to deal just with Netduino, here is the sample program where are all-six the different ways to use the library.

http://cetdevelop.co...s_MF/Program.cs

 

That is, if you compile the source as-is, you'll have a TCP-Master Netduino. To create the TCP-Slave counterpart, just un/comment the proper "#define" at the top of the module.

 

What else do you need?




#56640 Micro-JSON for Netduino (and PC)

Posted by Mario Vernari on 05 March 2014 - 12:36 PM

In case you need a lightweight and simple JSON parser and serializer...

http://highfieldtale...etduino-and-pc/

Good luck!




#56160 Extending Analog Input using 4017 and 4066

Posted by Mario Vernari on 18 February 2014 - 04:36 AM

The idea is great, also because many users are asking for that.

Just two considerations, though...

 

First off, if you use plain "old" 4017/4066 (CMOS logic) instead of the more modern 74HC4017/74HC4066, I'd connect their supply to +3.3V rather to +5v. That's because their logic thresholds are less incline to be used in mixed voltages circuits.

(NOTE: I'd just wonder where were you able to find such a 30+ years old chips!)

 

Secondly, why didn't you choose a simple de/multiplexer such the 74HC4052? A couple of those chips yield you 16-to-4 analogs inputs. And they are explicitly addressable, without any needing of pulsing the 4017's clock.

http://www.nxp.com/d...4HC_HCT4052.pdf

 

Good luck!




#55788 AnalogInput - options when I need more than six?

Posted by Mario Vernari on 01 February 2014 - 06:55 PM

As stated in my previous post, the HC4067 is also suitable.

Sparkfun offers this chip as well, which looks even better than the HC4052:

https://www.sparkfun.../products/10652

 

From my perspective, being both the chips SMD, they would be a nightmare to sold manually: I'd choose a DIP.

Apart this personal consideration, the comparison is between the HC4067 and the TS3A5017. They both act as a "switch" with a small resistance.

 

== HC4067

Pros: a single 24-pins chip offers a 16 channels expansion; good price;

Cons: the resistance of the selected route isn't very low (about 70 Ohms);

 

It needs just one analog and four outputs.

The software would look as follows:

 

for (int i=0; i<16; i++)

{

  a.Write( ... );

  b.Write( ... );

  c.Write( ... );

  d.Write( ... );

  adc.Read();

}

 

 

== TS3A5017

Pros: very low resistance (10 Ohms)

Cons: you need two 16-pins chips; the price is 3x; can't work with voltages greater than 3.3V (that's the same limit of the Netduino, however).

It needs 4 analogs and two outputs.

The software would look as follows:

 

for (int i=0; i<4; i++)

{

  a.Write( ... );

  b.Write( ... );

  adc0.Read();

  adc1.Read();

  adc2.Read();

  adc3.Read();

}
 
 
I think that you should say what's better. I'd like more the second chip, but if you don't have performance yet accuracy problems, the first chip is good as well.
To sum everything up, the HC4067 is an average quality chip, while the TS3A5017 is a good quality one.
Ciao.





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