Hello Dan,


This is exactly what I am doing today. However, I would like to see if I am getting out of my mind or if there is someone else who is experiencing the same problem... do you have this problem?


Thank you,


Igor.

I do indeed. I wouldn't say so much that is is a defect as it is the way that netmf and VS work together. When VS is uploading the projects to the board, it expects that every project is needed. And its kind of a crap shoot as to which assembly gets picked as main.

Most of the time you won't have multiple non-related assemblies in a solution, so for most people its a non-issue.

-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

Hi Chris,

I did know that screen! Thank you!

However, I really want to deploy a single project, the one I marked as startup project! But this is not what is happening (see my reply to Stefen).

What do you suggest?

Igor.

Igor, an easier method than fighting with the config screen is to unload the projects you don't want deployed to the Netduino. That is the method I use.

-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

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

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

Hi everyone,

You really need to be using a buffer between the Netduino and the relay.
There are two hazards connecting it directly:

• relay coil draws more current than the Netduino can handle,
• back emf causes a voltage spike on the Netduino output pin.

Both hazards could destroy the output pin and possibly other parts of the Netduino.

To add to what Paul said, you really should add a pull-down resistor. Yes, you can specify when you create the OutputPort that you want it to be internally pulled down, but what about the 2-3 seconds that it takes for the Netduino to boot up? You don't want to have the state floating. If the pin floats high, it would cause the relay to trigger. While in this case the worse that would happen is the camera would take a picture. If what your triggering happens to be the mains, or a garage door, or some other device it could create a real safety hazard.

To add a pull-down resistor, add a 4k3 (or 10k) ohm resistor between the base of the transistor and ground. This will ensure the pin is *always* in a known state. Its either at ground, or high because you've commanded the pin high.

-dan

I want to use it to monitor the operation of a 220V pump. I don't need to get any sort of accuracy, I just want to be able to sense when the pump is powered on and when it is off.

This might be to simplistic for your needs, but what about mounting a reed switch next to the motor? It should trip when the motor engages.

-dan

Usb devices do have a discovery mechanism but I am fairly sure the Netduino usb connector cant be configured as a usb host anyway.

Magpie,
IIRC, in the latest 4.2 beta firmware, Chris and company have added basic USB host support. I believe they have a keyboard working?

-dan

I've been theoretically working on this for my project but haven't put it into practical use, but it won't work exactly the way you are thinking.

I have a number of sensors built into my project but there are 3 sensors that I have not added in, because I want them to be add-ons where someone can plug an external box in that contains 1 of these 3 sensors. In my case all 3 sensors are I2C.

The scenario I have on paper is to try and initialize these sensors one by one. If the Initialization sequence fails (basically it is not found on the address) then it sets a flag so the code doesn't try to get readings from those sensors.

But, as I said, it is theoretical right now and will only detect the fact that these 3 specific sensors are or are not connect.

Dave,
One wire has the ability to do pseudo discovery in that each device has a unique 64 bit serial number burned in at the factory. I haven't had a chance to look at the specs to see if there is a numbering convention one could use to do discovery of the actual type of the device.

-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

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

Thanks Chris.
I happen to have a USB one, but it seems a much more complicated affair to get that working without a USB Host shield.
I'll probably rather get an RS 232 one.
Thanks for your input.

If you open up the device, I bet you'll find a TTL serial->USB converter chip. You could hack it and pull the data right from device before it goes into the chip. The two most common serial->usb chips are the PL2303 and FT232.

Doing that will keep you from having to buy another barcode scanner.

-dan

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

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

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

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

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

What my project intails so far is I will need to controll about 8 air actuated valves. These will have the DIN connecter plugs. I would like to set this up with an 8 channel or better relay board to switch the valves. So what would be the most cost effective and simplest way of doing so?

I will need to input to the Netduino as well with a few different devices. Prox switches, a thermo couple, some manual buttons. E stop for instance. Id like things to be expandable incase I might need to add some stuff later on. Im in the very beginning of the design faze and this is one of the most important parts. So here I am

I would design my own shield (daughter board). Its not terribly complicated, if your interested I can share mine with you. The one I've built has two relays, and 1 or 2 inputs, and a couple of transistor driven output. You could easily take what I have and scale it to your needs.

The one caveat with my design though is its one pin per output/input. You can easily change that though if you need my by using some '595 chips for output. A '595, and its equiv on the input side allow you to control a virtually unlimited number of inputs/outputs from just three pins by using SPI. Or, you can wait until Secret Labs produces a "Mega" version of the Netduino (hint, hint) which has many more digital I/O's

-dan

This information would do well on the wiki!

Hello to all, I am new to the Netduino board programming and I would like some help or advise on getting started and creating cool projects.

all help and advise is greatly appreciated!

Welcome to the community!
What kind of issues are you having? What kinds of things would you like help on?

-dan

I'm not very good at this yet, so, I was hoping that someone might be able to point me in the proper direction.

I have an application where I would like to use 2, 4 digit seven segment displays. The P/N's are BL 056C 4343UHR-11. I will be using a Netduino or a Netduino Plus (I have both). There are 14 pins on each set of 4 digits displays. I think that what I need is something like Adafruit's LCD backpack, but for LED's. I can also use some LED IC's; or, I am going to have to use a Go and gang the shields; but, I am looking for something a little more elegant (not to mention portability is a concern).

I would like to know is there is a backpack analog for LED's.

In earlier posts, there was a mention of a "SandBox". The link went nowhere. Is there a "SandBox"?

I'm not aware of a "backpack" for 7 segment LED displays. But you can easily use a shift register to drive the displays. This will cost you 3 pins on the Netduino, but gains you a virtually limitless number of pins. You can either use 4 8 bit shift registers like the ever popular 74xx595, or two 16 bit shift registers like the 74xx676. They do have 32 bit shift registers, but I can only seem to find them in surface mount.

-dan

Hi All,

This is my first post so I hope I have put it into the correct section. I am also very new to electronics.

I seem to be having a little trouble with this Reflective Object Sensor. I am building a CNC pipe cutter and I am using this to measure the degrees on the chuck side. There doesn't seem to be enough current through them to even switch a opt-copouler on.

Second Question:

Is it possible to use this on the Netduino or will it lose count.

Thanks alot for a wonderful product. It is amazing what it is possible.

I will be posting my project up when it is complete... and all the software.

Thanks for the help in advance.

Wes,
Welcome to the community! Can you please post a schematic for how you are driving the sensor? This will help us figure out where the issue is.

-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

Hi Everybody,

This is my very first post or question.

We have a project where the employees will use a barcode reader (serial rs232) and a number pad (serial rs232) to check the employee number and a number that defines the number of operations they make every certain time.
After that is made we want to use a client server connection where the netduino will play as client to send that information to a server.

I am struggling with the socket part because I an not able to find some code about it, could you guys give a hand?
Regards

Francisco, welcome to the Netduino community!

There has been a lot of good sample socket code posted to the forums. I would search for socket, or webserver. This sample code is a webserver, it primarily shows how to accept incoming connections on the Netduino, but you should be able to adapt the code to your needs.

Another project to look at is Home Automation with Netduino and Kinect (source)

-dan