I discovered the Netduino a couple of days ago!
I have recently started development of internet-connected devices using the Arduino Uno and an Internet shield.
I am intriguded by the power of C#, multithreading, debug and the many other features of Netduino that make it easy and fast to develop internet-connected devices.
There are, however some drawbacks: limited product range, limited supported devices and related code, limited competition (price), limited support (just this forum?), fewer sample code available, ...

You have the experience, so help me make an informed decision:
1) Based on your experience, what are the 5 key reasons why Netduino is a better development tool for developping custom internet devices that Arduino

2) How do you deal with the restrictions/drawbacks compared to Arduino to reduce their importance

One of the big reasons for me why I use the NetMF platform using Netduino over Arduino is debugging. With Arduino, without going through a lot of gyrations, you have two basic ways of debugging. Serial.println, and flashing an LED. Serial.println works fine if you don't need to use the serial port(s) for other purposes.

With NetMF, you can do Debug.Print (or is it Console.WriteLine - don't my code in front of me), write out to a serial device, twiddle an LED, and most importantly, single step through the code to inspect what is actually going on. Another big thing is the code that you write, is the code that gets uploaded to the board.

With Arduino, if you use the Processing language and Arduino IDE, what you write is not what gets compiled and uploaded. A good example of this is some code I wrote last week, one of my preprocessor directives was wrong. The output from GCC which the Arduino IDE spit out said there was an error on line 133. My code didn't have a line 133. So I had to turn on verbose compiler output, so I could see where the actual file that the Arduino IDE was feeding to GCC was. Then open that file up and see what the actual error was.

That said, both platforms have their strengths and weaknesses.

Another big one is interrupts. Only pins D2 & D3 (IIRC) can be used to trigger interrupts. On the Netduino, any pin can trigger an interrupt. Interrupts are useful to have the microprocessor tell you when something has happened, instead of having to constantly monitor the state of a pin, and do your own checking on if the state of the pin has changed, and if that state is one you care about. For example, you can trigger when a pin goes high, goes low, or both.

-dan

Thanks for the reply. This sounds promising. What is the largest SD card the netduino plus can support? I can see myself having the main application on the main memory and loading and unloading dll's from the SD as needed.

Chris, Stefan, Mario, etc, correct me if I'm wrong.

You can't unload an assembly after it has been loaded. In the regular framework world, the way you handle that is creating a separate AppDomain and unload the entire AppDomain. I don't know if something like that is possible with NETMF though.

-dan

Hi,
Someone has some advise on how make some pages on netduino webserver protected by login?
Is possible to use browser session?

Thanks

As far as I'm aware, the webserver implementations for the Netduino do not support HTTP Authentication. It would be fairly trivial to add support for basic HTTP authentication. But be aware that the credentials for basic auth are encoded, NOT encrypted.

-dan

Dan, I feel your pain! I had to chuckle about the engine block heater! Your bio doesn't say where you are at but I remember well the "dipstick heater" from my youth in Rhode Island! What are they? 100W? Not much good when the temp is at -20 degrees...

Good points about the safety switch, aka GFI (or Ground Fault Interruptor). But it only works when the wiring is correct: in the U.S., the AC Neutral to the large, wider slot, the AC Line to the shorter slot, and a GROUND to the half-moon slot. Get the line & neutral reversed and your at risk - even with a GFI. When I lived in Germany, the locations were determined by relative location to the ground lug. It is easy either way to mis-wire by a "do-it-yourselfer".

Bill,
I live in Anchorage, Alaska, USA (Yes, some people forget we are part of the US :{). Normally temps get down to about 20F, but at times to -20F.

The way I remember how to wire up an outlet is "B2B - Black to Brass." All the outlets I've dealt with all have a brass and an aluminum side corresponding to hot (or black) and neutral (or white).

-dan

@Dan: aren't you scared about the quake? I guess the your's in one of the most dangerous areas for the quakes!
I have seen some of medium/high intensity here in Italy, and I must confess that's horrible!
Anyway, despite this dark page, my wife loves to visit those places!
Cheers

Mario, I missed your reply until today :/

The quakes don't bother me one bit. You get used to them after 26 years :-) Only one had me concerned, and that was a magnitude 7.9 quake. Usually, the ones we feel are in the magnitude 4 to 5 range.

-dan

I am working on a circuit that will be able to drive a 115VAC half wave vibratory feeder using the Netduino. I attached the circuit diagram to the post.

As I am not realy experienced in this I was wonding if someone would be able to have a look at the circuit I designed and provide feedback to ensure that the circuit is sound. I really do not feel like killing my Netduino (or myself) by connecting to mains... I know that I lack fuses in the design as well as values for components, I will calculate those later.

Any help with this is much appreciated.

Regards

From your schematic it looks like you are using an optoisolator to then switch some stuff to then turn on the mains. Is that correct? If thats the case, you should look at the Arduino relay circuit.

-dan

AC MAINS- it's about 30 years, here in Italy, that in any house/office it must be installed a safety switch. In US that's not mandatory? Basically it is a switch (normally closed), that opens as soon the difference of current between the hot and the neutral are above 30mA. This would be the typical situation when you touch accidentally the hot wire, but all the current flowing through your body is going toward ground. That makes the switch opens.
It works very well, and you almost don't feel anything: too fast to feel the shock.

Cheers

Mario,
We have much the same regulation here, except it doesn't apply to all outlets. Outlets in a wet location (WC/bathroom, kitchen) and exterior are required to be GFCI (the technical name for the "safety switch" you mentioned), or protected by an upstream GFCI or GFCI breaker.

On the one hand they are nice to keep you from frying yourself, on the other hand they can be a complete pain in the butt. I have to replace the exterior outlet I plug my car into in the winter once every year or so because it goes "soft" due to the draw of the block heater on my car.

-dan

Dan,
I am humbled.
Anchorage, eh? Makes my winters in R.I. seem like the Bahamas.

On my bucket list I have "trip to Alaska". I hear many good things about your beautiful state. I will get there someday.

You are spot-on on the colors. "Black-on-Brass" "White-on_silver". When wired corerctly WHITE & GREEN cannot kill you. But, Never trust the colors.

Am I being a PITA about this subject?

Regards,
Bill

We aren't that much different than the lower 48. We just have longer winters and shorter summers. Winter typically starts mid September and runs till mid April Oh, and its dark here, at the winter solstice the sun comes up around 10:30 and sets around 3:30 .

When you come, come in the summer time. June is a good month, not to hot, its usually pretty sunny. August is the worst time, it rains almost every day. In fact, last year it rained every day for 36 days in a row

As to being a PITA on the mains issue, I don't think you are. People need reminders sometimes that the mains can hurt you :-)

-dan

With a netduino classic or plus you need a TTL to RS232 converter. I used two successfully:
http://wiki.netduino...hifter-SMD.ashx
http://wiki.netduino...-to-Serial.ashx

perhaps this thread could help you with code:
http://forums.netdui...rt-code-review/

You can also wire up a USB->Serial adapter directly to the serial pins on the Netduino. But be very careful. Some USB->Serial adapters output 12v and that will cook your Netduino (unless you use a level shifter). The USB->Serial adapter I have happens to put out TTL levels.

-dan

Hi,

I am working with the rf modules. I have two netduino boards to whome i want to connect the receiver and a tramsmitter. Now i need the possible circuit design and the code for sending the numbers from 1 to 100 using the c#

Can any one help me out with this ??

If you want one Netduino/Arduino/PC to just be a receiver, and one Netduino/Arduino/PC to just be a transmitter, then WRL-10535 RF Link Transmitter - 315MHz and WRL-10533 RF Link Receiver - 4800bps (315MHz) would do the trick. They are US $3.95 and US $4.95 respectively.

Keep in mind that each module *only* does one direction. If you need bi-directional, you would need to either go XBee, or equip each unit with a 315MHz and 434MHz unit (one in send, one in receive).

-dan

Rexz, welcome to our place.
Your idea is theoretically realizable, but you need a powerful platform for both the recording and the playing side.
The Netduino hardware itself is very powerful, but you should wipe out the .Net Micro Framework, and use pure native code.
This consideration worth also for the Arduino side: I'm not sure an AVR would be able to manage a real-time stream.
However, it depends on the sound fidelity, though.
Cheers

Mario, the new Arduinos are moving to an ARM chip (Atmel SAM3U at 96 MHz) and should be able to handle this task with ease. Arduino launches new product at maker faire

-dan

There's a series of model kits that are coming out with RFID chips (circuits) imbedded in parts that connect it to a game.
As the Japanese hardware is not available in the UK (and probubly never will) how do I go about getting a pc based solution to this problems.

The first thing you have to identify is what freq does the RFID chip work at? A lot of your proximity cards are either 125 kHz or 13.56 MHz. If the tags your trying to read work at either of those frequencies, then you are probably in luck. The next thing you need to figure out is what is stored on the RFID chips? Is it a simple 16 byte chunk of data? Or is it a 1k block? How does the particular RFID chip encode the data?

Once you figure those things out, you can more than likely find an off-the-shelf chip to read the RFID chip. Then its a simple matter of buying the chip and either wiring it up to a Netduino/Arduino to do any processing that maybe needed, or outputing it to serial and reading it on your PC via a serial->usb converter. All the RFID chips I've dealt with output straight serial.

-dan

Hard to tell how much people are color blind. Only males are affected.

Not 100% true, females can be affected by color blindness as well, but the rates are much lower. 8% for men, and 0.5% for women - Color blindness

What I want to do with Netduino, is plug my Futaba Receiver's digital channels one to four into Netduino as inputs, and then read the pwm values in my C# code, interpret that, and then control things with it.

Anthony, although it would require a change in xmitter and receiver, have you looked at the Spektrum stuff? Their receiver spits out straight 115,200 serial with all the channel values. A good friend is using those with an Arduino to build a product for the R/C world.

Just a thought, although I know buying a new transmitter and receivers is a spendy proposition.

-dan

Why? Well, couple thoughts come to mind:
1) Not really sure what I'm doing
2) I was working with what I had and then tried to add in pieces to that. Something else to remember - my first regulator is also converting AC -> DC, not just dropping the voltage.

So that 5V can function either as a 5V out or a 5V in?

Would someone mind also clarifying one of my earlier statements about how to properly add up the power usage of the various components (which are running at different voltages)?

At first I was just adding up the mA, regardless of voltage. But then it occurred to me that it probably doesn't work that way. It seemed to make more sense that I should convert any particular value (such as the 60mA @ 3.3V for the LCD) to VA. I can then add up VA to make sure I don't end up accidentally exceeding the rated value of the AC->DC converter.

I suspect given that the LCD turned out to be much smaller than I initially understood that this won't actually matter - but I would like to know the proper way to calculate that for the future.

Thanks

Yeah, it can function as a 5v in, there is no diode on it. So, keep that in mind and be very careful not to swap the positive and negative rails.

The easiest way to figure out your entire load would be to convert your power usage to watts, Watts = Volts * Amps. 1 amp at 5 volts is the same power usage as 0.5 amps at 10 volts. So if you do your calculations purely on the amps used, you would be off.

So for that LCD, which consumes 60mA at 3v3 you have W = .06 * 3v3, or .2 watts, which is a negligible amount of power. For the relay board, you have W = .5A * 5v or 2.5 watts. And the Netduino is W = .2A * 5v, or 1 watt. So total we are looking at 3.7 watts.

Now to take that and figure out how many amps at 5 volts you need. 3.7W = A * 5v, 3.7W / 5v = A, A = .74. So to power what your looking to power, you would need a 5 volt, 740mA power supply. Now, that number doesn't account for any losses that occur with the 3v3 regulator, and it gives you no head room.

So if it was me, I would use a 5v, 1A regulated power supply.

As to your comment about your first regulator doing AC -> DC, you can easily convert AC -> DC by using a bridge rectifier. You can make one yourself with with 4 silicon diodes like the venerable 1N4004, or you can buy one pre-built in a package for < $1.

-dan

My intent was to get something like this DC stepdown. Split the 12VDC before it goes into the Netduino and run it through this to step it down to 3.3V.

Why buck it down to then run it through a linear regulator? Very inefficient, and the linear regulator will be running quite warm. I would buck it down to 5v, and then put the power into the Netduino via the 5v pin on the header. Then for your 3.3v needs, you could linear regulate it down to 3.3v with a LD1117. You wouldn't be eating up nearly as much power to regulate 5v down to a 3v3, vs 12v regulated down to 5v (which the Netduino does when you feed it via the barrel connector).

-dan

Just as an update, while looking for a recommendation on which Ocilloscope to buy I came across this thread, the RIGOL DS1052E was mentioned as a good scope (I am sure that it still is).

While this model can still be found for sale I found that it has been replaced by the RIGOL DS1102E for the same price range as the older model (was $795.00 now $399.00) and has a 100mhz bandwidth. RIGOL DS1102E

The DS1102E doesn't replace the DS1052E. The DS1102E is a same board, chips, components, etc as the DS1052E, except it has a different label on it, and bit has been twiddled in the firmware to allow capture at 100 MHz. As @nakchak mentioned, with putty (or any other serial terminal program) and some very easy instructions on the net you can turn your DS1052E into a DS1102E.

-dan

However, rather than use a remote - I decided I want to wire my device directly to the door opener open/close terminals. My question is can I still use these optoisolators http://www.sparkfun.com/products/314 that I've already purchased on sparkfun to act as my "switch"?

Mike,
Just use a relay. The part count is low, you just need a resistor, transistor, diode and the relay itself (I'm guessing you can leave out everything but the diode if you use a solid state relay, not sure on that though). Its easy to wire up as well, and it will isolate your garage door from your Netduino. This relay from Sparkfun will do the job nicely.

I'm sure others on here can post a better way, but I'm not an EE so I tend to go with pre-canned circuit recipes as solutions for me.

-dan

I need to then check to see when the door has been closed and a message back to the connected mobile device via the USB, Bluetooth or serial.

There are many ways to see when the door has closed. Does the mag lock your using provide an output which toggles high/low when the door is closed/open? If so, you need to verify the voltage it puts out is within the Netduino's params, but you can easily hook that up to a pin on the Netduino.

Another method is a simple normally open momentary push button. Mount the push-button such that when the door is fully closed (with the mag lock engaged) the button is depressed. Then wire the 3.3v pin from the Netduino to one lead on the switch, and the other lead to a digital I/O pin on the Netduino. Then its a simple matter of setting up the pin as an edge triggered input port in code and acting upon the change.

-dan

I'm not planning on using the NetDuino Plus since we're adding our own RF modules to the serial ports of the NetDuino ... but you just gave me an idea ... I'm wondering if I can query a unique ID from the RF module!

If Chris has any other ideas ... that would be great!

Another option I just thought of is using one of the many I²C EEPROM chips? Sparkfun has them for $1.95 each.

-dan

I'm working on a project where we are going to be having a large number of Netduino devices talking to our SaaS Platform. When we ship the units, they are going to talk to our platform using some simple web services, but we have to uniquely identify each unit.

Is there *any* way to programatically obtain a unique ID for a Netduino to use as an ID in the web services?

If not, we are thinking of a few other ways to do this ... but I was hoping there could be something?

Scott

I'm sure Chris has better/different ways, but what but about using the MAC address? If your using the Netduino plus you can write a unique ID to an SD card and store it on there. Depending on your timeline, I believe the ability to read/write a small amount of data to the on-board EEPROM is coming in NETMF 4.2.

-dan

Hi Kiran,

Glad that you're up and running! *whew*

If you're powering your Netduino via USB or the power barrel, then the 5V pin on your Netduino should provide a 5V source for your circuit.

Please note that USB power is "roughly" 5V and could vary from 4.5V-5.5V in range. But it's close If you need a regulated steady 5V, then plug in your Netduino using a DC power adapter.

Chris

To add to what Chris has said, do NOT plug your board into both USB and power it via the barrel jack. Its an either or situation, unless you want bad things to happen IIRC.

-dan

Please advise best way to see if some on is available to discuss further and
agree on price and time frame.

Sorry, we aren't going to do your homework :-)

-dan

I don't have much experience about LiPo-charging, but to be honest, I don't like the charging/detecting circuit above.
I am not sure, but it seems that you have to balance the charge when two or more LiPO batteries are connected together. Another clue is that there's no LiPo batteries chargers for series pattern. You find balanced chargers, single-cell chargers, but no double-cell chargers...at least I wasn't able to find them.

Mario, you are very much correct. LiPo batteries *must* be balance charged.

The other thing I would say is if you are charging LiPo batteries, you really should get a "LIPOSACK." Should something go wrong with the batteries, it can mean the difference between some smoke damage in your house and a full on fire.

-dan

Darrin, anytime you can post the code is appreciated.
I'd like to start learning G code better so I can make a simulator in autocad.
If anyone ever needs help with Autocad, its what I do for a living, so happy to help (for free...).
I'd like to further Darrin's work though, not make my own parser.

Where were you on Sunday night when I was battling AutoCAD :-) I actually ended up writing a craplet to spit out some g code to do what I needed (drill a hole every .5 inches along the x and y axis in a 12"x12" board. 3-4 hours with AutoCAD, and nothing (I'm an AutoCAD newbie), and 5 mins with some code and done :-)

The whole point of my exercise was to build the top piece of the vacuum hold-down table for my CNC machine :-)

-dan