Hi Mikeo2721,

I wear out a USB port on my computers just about every year. They're rated for thousands of insertion cycles--but it's amazing how many times I unplug/plug things around here testing engineering samples, etc.

Anyway, let's make sure we get you up and running...

Chris

Chris, If you wear out a USB port on a motherboard that can be an expensive fix ;-)

Have you considered using a USB extension cable (male on one end, female on the other) and leaving it plugged into the PC continuously? That way it would be the extension cable that would wear out, not the socket on the PC.

The code is far from 'perfect' but seems to work OK. There is one known issue. On rare occasions, the message string sent to the Netduino for setting the PWM has missing data. The Netduino will return a message informing you of the problem. To be blunt, I have no idea why, but at least it does not happen very often. I live near the BIG Chicago airport and I have issues with electronic items in the home at times. I 'think' it is from aircraft transmissions of some sort. Anyway, a plane is usually flying over and then have strange thing happen around here. Like hear voices on the TV and FM radio.

The usual way to handle situations like this, (namely sending data over noisy communications channels where the message can be garbled) is to include a checksum ( http://en.wikipedia.org/wiki/Checksum) with the message.

Basicly the sender computes the checksum and includes it with the message. The receiver then gets the message and re-computes the checksum to confirm that the computed value matches the checkum received. If they do not then the receiver knows the message has been corrupted and treats it accordingly. (One standard practice is to simply ask the sender to re-send the message).

This may or may not be overkill for your purposes.

A power sub-station with voltages measured in kilovolts and 1000s of Amps is really a special case where safety is paramount. As suggested in another response only properly designed industrial equipment tested and certified for such an environment should be used.

For others who might be considering measuring voltages in a residential location such as 120V or 240V (still lethal) there is a good "general" model to follow.

A Netduino (or any other micro-controller) is generally designed to operate on 5V or less (3.3V in the case of a Netduino). It is not designed to survive the application of high voltages (think of it this way, if it would kill you, it will kill a Netduino).

The best approach is to keep the high voltage (or current) on a separate board from the Netduino,

There are many Digital Multi-Meters (DMMs) out there which will output their readings on a serial port. The DMMs are designed and tested to be safe and reliable for measuring voltages and currents within their design specification. You can connect such a DMM to a Netduino via the serial interface (you may or may not need a level shifter such as a MAX232 but that is another issue).

Here is a post where someone used a DMM from Radio Shack in conjunction with a computer: http://www.linuxtoys.org/dvm/dvm.html The price they paid for the DMM seems high (old post perhaps?), I know I bought one on sale (different model) for about $30.

Perhaps there is some confusion about "localhost". It refers to the current computer, so if you use localhost on your PC, it refers to the PC. If however you use localhost in your Netduino program it would refer to the Netduino, not the PC. If you want to have the Netduino talk to the PC use the ip address of the PC, not localhost.

Hello Mozsi and welcome to the wonderful world on Netduino!

I am not a Mac person, but I can tell you that having simple routines that allow reliable communication between a microcomputer and a desktop (e.g PC or Mac) is something that virtually everyone struggles with. The key hangup is reliability.

To be useful in the real world communication needs to be resilient; automatically recovering from such things as power failures, cables being unplugged and being plugged in again etc. If that is something you can workout it will be a great service to us all.

I don't know if this helps, but here is a project someone is doing for the Arduino: http://robotgrrl.com...no/matatino.php

IBM has contributed an open source implementation of the Paho, a simple protocol for sensor and machine to machine communication via the internet.

See:
http://www.adafruit....hings-protocol/

&

http://www.pcworld.c...ed_devices.html

This looks like a good way to get Netduinos communicating, has anyone used this Paho protocol?

I too have the HelloPachube example running on a Netendo Plus powered by a wall-wart. It has been running continuously for a couple of weeks now. It runs fine and I can see the data on Pachube. I have definately had a few network hickups as well as outages lasting several minutes. The Netduino has not locked up once. As they say, your mileage may vary ..... Also a big thank you for your great book, I highly recommend it!

Need a project (c#), in breadboard form to include the following:
2 Temperature/Humidity sensors.
1 RFID reader
1 Wifi
1 GPS
1-2 button(s)
1 display 16 x 2

We would all be glad to help you if you re-phrase your question, For example if you stated "I want to use a Netduino and would like to know what GPS, WiFi and Display shields work well with it?" I am sure you would get several well informed answers. As you probably know, shields simply plug into the Netduino (or Arduino for that matter) and generally are able to be stacked on upon another - no breadboard required.

Perhaps you are looking for a solution without any circuit boards? Did you mean you want to use a Netduino mini plugged directly into a breadboard along with other components? Your request is not clear.

Finally you do not state if this is intended as a "one off" project or a pre-production prototype. The reason I ask this is you should consider that there is already a readily available device that has:

RFID reader
Wifi
GPS
button
display

it is called a smartphone. All you would need to add is the two Temperature/Humidity sensors. Are you familiar with the Android Open Accessory Development Kit?

If you would like to discuss this further please send me a private message here on the forum and we can arrange to speak on the phone if you like.

Another option is to get a good used analog oscilloscope, I picked up a used Tektronix 100 Mz dual channel unit that is absolutely top quality. If you shop around you should be able to find one for $100 or less, often much less. Look on Craigs List and E-Bay. It is best if you find one locally as they are big, heavy and easily damaged in transit if not packed properly for shipping. Plus if you buy locally you can verify that it works before handing over your cash. I have heard of many people who were poor students without much money who have asked around and gotten used scopes for free, although that route will probably take you longer. Good luck!

How do develop and deploy for the Arduino in Visual Studio:

http://www.adafruit....-visual-studio/

Anyone planning on attending the session Having fun with Netduino by Carl Bergenhem and Chris Gilmore this Saturday (29-OCT-2011) at the New England Code Camp in Waltham, Mass (USA)?

More info at: http://codecampboston.eventbrite.com/

First off, let me say how glad we all are that your son is safely home again. Also welcome to the Netduino community.

Before proceeding it is extremely important to remember the difference between a hobby project and a safety critical device involving life or death. The "gold standard" for being found in an emergency is a EPIRB (and it's little brother, the Personal EPIRB, or PLB that fits in your pocket). These are extremely rugged, waterproof, tested to the highest standards and have long life batteries. Unfortunately one needs to press a button to activate them, so this is probably a "show stopper" for your application.

Another common device with a built in GPS and communication capability is a cellphone or smart phone. In an emergency authorities can easily locate a cellphone provided it is turned on and within range of a tower. It is highly unlikely that you can engineer a solution with similar capabilities at a lower cost than a used cellphone.

As far as a hobby project is concerned, you might want to consider fox hunting, where you simply attach a small transmitter to your son that sends a radio tone for a couple of seconds every minute or two. To locate the transmitter one only needs a simple receiver and a directional antenna. This is how biologists track animals in the wild. See http://www.predatorc...diotracking.htm for details. Newer versions often include a GPS as well. Here is a link where someone did it on the cheap http://www.thefintels.com/aer/frs.htm to find model rockets.

Finally there are commercially available pet tracking devices such as the Garmin Astro.

We actually did a bunch of engineering on a SAM9G45-based open-source Gadgeteer mainboard. Basically, we offered to create a $99 open-source Gadgeteer mainboard, an open-source NETMF port for SAM9G45, and a bunch of open-source Gadgeteer accessories if MSR would open-source the Gadgeteer software. They worked hard on that and were able to open source the smaller core but unfortunately they didn't have the engineering resources to write all the Gadgeteer drivers.

So they felt that they needed to launch Gadgeteer with a closed-source partner. So we had to scrap a ridiculously awesome board.


Chris

Is/was your mainboard similar to this: http://www.armkits.c...CFdU55QodtTGCMw ?

From: http://channel9.msdn...mework-v42-RTWs

few months ago I mentioned that the next version of the .Net Micro Framework, v4.2, was in beta, Netduino is opening up to an wider audience with the .Net Micro Framework v4.2 release.

Well it's beta no more!

Version 4.2 RTM Today!! (Updated)

We are glad to announce today the RTM of the .NET Micro Framework version 4.2. You can download the SDK and PK as well as the all sources from our Codeplex project, client_v4_2 branch, at change number 13620. (We will be distributing 4.2 solely through the Codeplex site this time and not on downloads.microsoft.com)

Version 4.2 of the .NET Micro Framework Porting Kit provides the following new features:

Remote Firmware Update: The .NET Micro Framework SDK and PK now support updating your device firmware remotely.
Complete Cryptographic Object Model over PCKS #11: Most types and algorithms used in the desktop framework are now supported. PKCS #11 allows extensibility at the firmware level for adding new cryptographic tokens.
1-Wire, PWM and A/D object model: Support for PWM and A/D operations is now provided as a standard interface. 1-Wire is provided through a community development effort
SNTP and FTP (client and server): Support for SNTP and FTP is provided as a community development effort.
StringBuilder and Regex types: Support for StringBuilder and Regex is provided as a community development effort.
Transcendental functions for doubles in System.Math
VB.NET: The SDK now support VB.NET.
Support for Cortex M3 devices with STM32 processor family samples: The support for the STM32 family is provided as a community development effort and features two solutions for two different development boards. See the Porting Kit for details.
PKStudio: PKStudio supplements SolutionWizard to create solutions for the Porting Kit environment. See the Porting Kit distribution for details. (PKStudio code can be in the community branch under %SPOCLIENT%\CLR\Tools\PlatformDesigner\PKStudio and the binaries are instead in the %SPOCLIENT%\Tools\bin\PKStudio directory ready to use)

...

You can find white papers about crypto, firmware updates, and the Codeplex distribution in general on the documentation page of the project. You can find the general documentation on MSDN. PK documentation is in the distribution, under the documentation directory (you will find there also the full .chm help

I just did a blog post at: http://www.bitsconne...-crappy-surplus describing my experience whit the BOCS, including photos.



As a teaser, this is an image of what I added to the box.

For those of you following, I had no takers for a box opening party, but hopefully we can organize some Netduino Days at hackerspaces and other locations in the future.

The BOCS left Phillips, Maine (USA) today (Tuesday, 11-OCT-2011) on its way to David Stetz. The Post Office tells me it will take 2-3 days, so hopefully David will have it by Friday. I took photos and will post them here later today.

The BOCS arrived in Maine! The box arrived here in Phillips, Maine yesterday. Is anyone interested in having a box opening party? I know Phillips is rather remote, so I am open to traveling to Portland, Bangor or Augusta ME to meetup with anyone who would like to share in the fun. I am even open to traveling to Portsmouth, NH if that is better for people. Please respond if you are interested. I do not want to hold the BOCS up too long, so we need to do thus soon if you are interested. Today is Tuesday, 4-OCT-2011. If nobody responds by tomorrow night, I will simply open it by myself and then send it along on Thursday.

Tell us more about your sailboat,what kind, how big, do you liveon it etc.?

I have a LeComte NorthEast 38 sloop.

Many boats have expensive batteries,and monitoring them properly can make them last much longer and save a ton of money. Properly maintained (as in a data center) deep cycle batteries can last 10 years. Many boaters consider themselves lucky to get 3-4 years before replacing them.

If you want to do a really good job of battery monitoring consider using Kelvin 4-wire leads (http://en.wikipedia....erminal_sensing )

Here is a nice presentation Powering your embedded devices with C# and .NET Micro Framework in which Netduinos are featured.

If you would like to see the .Net MF runnng on a M3 take a look at:

http://blogs.msdn.co...ce-project.aspx

I just ran across this excellent, simple guide to connecting external parts to a microcontroller: http://cq.cx/interface.pl#10

It is not Netduino specific, but would work with any microcontroller.

One caution, in his examples he often shows the voltage level as 5 volts, which would be fine for an Arduino or many other microtrollers. The Netduino is a Netduino is a 3.3 volt device so just replace 5 V with 3.3V in his drawings.

He describe how to:

Light an LED from a Digital Output
Read Switch Contacts with a Digital Input
Read a Digital Signal that Goes from 0 V (LOW) to 10 V (HIGH)
Read (with Opto-Isolation) A Digital Signal
Measure a DC Voltage Between 0 V and 15 V
Measure a DC Voltage Between -15 V and 15 V
Measure a DC Voltage Between 0 V and 1.7 V
Measure the Position of a Potentiometer
Measure an Unknown Resistance
Measure a Temperature
Output Characters on an LCD
Switch a 100 mA, 10 V Load
Switch a 1 A, 10 V Load That Always Stays Connected to Ground
Switch a 10 A, 40 V Load
Switch a 120 VAC Load

You are quite correct that the hardware is quite capable of handling this frequency measurement task with ease.

The issue is the .Net Micro Framework. If you are willing to forgo .Net and program directly to the chip in C, you can get the job done.

What s not as simple or easy is to combine the use of .Net with native code and direct control of hardware interrupts etc. It may very well be possible, and I hope you succeed as we would all like this capability. You should be prepared for some setbacks along the way.

Can an Atmel AT91SAM7X512 microcontroller support the functions of the Taos TSL235R?

I am still not convinced that I need to throw more components at this problem. Netduino has an ARM7 48MHz processor- why should we deny that there is plenty of speed right on this development board? If I were to remove the processor from the Netduino and program it directly, or remove the .Net firmware and run C/C++ on it, I am sure that this sensor would run fine. I've read in these forums that version 4.1.2 of the Netduino firmware is supposed to offer run-time native code interop. I've also read about someone's project called "Fluent", which runs code something like 20 to 30 times faster than the managed code. I've also read that you can run FreeRTOS on the Netduino platform. Can't you run a quadrocopter with FreeRTOS? Isn't that real-time?

Does version Netduino 4.1.2 have runtime native code interop? If not, when will it have this functionality? Where can I get this "Fluent" project? Where can I find resources on how to run my own C/C++ on this board?

I understand the opinion that more tools will help me solve this problem, but I would rather use what I have instead of having to then deal with connecting, learning, and powering these other pieces.

Thanks,

Nick

As others have pointed out, a Netduino is not the right tool when you require precise real-time programming. There are however lots of cheap micro-controllers that can measure frequency and report the results to the Netduino via I2C or many other ways.

One cheap way to do this is with a TI MSP430 board which only costs $4.30 delivered (https://estore.ti.co...-kit-P2031.aspx ) This is probably the cheapest way to do a one-off project and the TI chip has reasonably good support.

The best way to look at this is that there is no one perfect single board computer. The key is to use one appropriate to the task and remember that they are cheap enough that you can break the task down and use more than one board.

I see Arduino has announced several new products ( http://arduino.cc/bl...ast-at-arduino/ ) including a new Wi-Fi shield.

I wonder if it will be Netduino compatible??

Anyway they will have them at Makerfare in NYC this weekend, so perhaps someone can check them out.

Will anyone else be at ESC Boston (Sept. 26-29) http://esc.eetimes.com/boston/?

Interested in meeting up?