I have a 2gb microSD card that I pulled from my Blackberry and I plugged it into my Netduino Plus, and I noticed that it is very slow to read files. It is even slow when using a USB-to-microSD card reader. I am comparing to the speed of a standard USB drive. Are USB read times normally faster than microSD, or am I doing something wrong? Is there a way to read USB drives with a Netduino, i.e. with a compatible USB shield or something? I need faster read times somehow. Even a 20kb file takes too long.

Could be a problem with the SD card... I'm re-formatting it now. I don't have a second one around to try. Perhaps the issue is more related to my code and what I am doing. I am reading a file off of the SD card via a Filestream, and then I am sending the data out onto the Netduino's UART to another device. I am sending it at 1024 bytes at a time, but I wonder if I am running into speed issues because of the fact that I'm re-assembling it for transport onto the UART. The other device also then has to process it. I'm not sure where the bottleneck is. I'd like to think it isn't my code, but that's also possible.

However the transistors are connected to the 5v onboard power, so I expected the output to be at 5V rather than 3.3v is that correct?

I have confirmed the NetDuino is outputting 5v on the 5v onboard output and if I connect the relay directly it works fine.

Any ideas, have I misunderstood something?

Thanks,

Charlie M

I don't quite follow this. Are you connecting the transistors to the 3v3 or the 5v on the Netduino? The Netduino has outputs of 3.3vdc and 5vdc depending on which pin you use.

Also, what is the application with the kettles? When you say kettles, do you mean like teakettles for boiling water?

However the transistors are connected to the 5v onboard power, so I expected the output to be at 5V rather than 3.3v is that correct?

I have confirmed the NetDuino is outputting 5v on the 5v onboard output and if I connect the relay directly it works fine.

Any ideas, have I misunderstood something?

Thanks,

Charlie M

I don't quite follow this. Are you connecting the transistors to the 3v3 or the 5v on the Netduino? The Netduino has outputs of 3.3vdc and 5vdc depending on which pin you use.

Also, what is the application with the kettles? When you say kettles, do you mean like teakettles for boiling water?

---> Edit, I think I follow now. Do you mean you are getting 3.3vdc from the I/O pins? That is what you will get. The I/O pins output 3.3v but are 5v tolerant. See the lower right corner of the spec sheet.


You will need to use the 5v supply pin to power your 5v device.

Oops, I didn't mean to double post! Sorry!

P.S., when it says that the I/O pins are 5v tolerant, it means you can connect a 5v signal input to the pins without damaging them.

Is it possible to boot an install of Linux with the on-board microSD card? Can I "auto-boot" Linux when the SD card powers up? I want to be able to run Linux on the microSD card so that the Netduino would basically become an MCU running Linux and I could then communicate to the Linux install from C#. Is this possible?

Hi,

Can someone please assist me with wiring this circuit? Thanks!

It's got going to work, it's missing the cold fusion reactor and the warp field coils!
Hmn I see it's missing the flux regulator and the sid chip!

I was having trouble finding scarab beetles, and my electric eel won't stay still, but this information throws another wrench into the works. Or maybe I just need to throw a real wrench and another solder blob in there somewhere as replacement for the other items? Hmmm... any other suggestions?

Euh... LOL!

"Not a resistor; wire just does this"

LOL

I've controlled 12VDC CPU fans using an NPN transistor and a PWM port on the Netduino. It works fine. Edit: I am trying to find a nice diagram for you. I will upload it here once I do.

File did not attach. See below reply.

See the attached file. I use this for reference all the time. While it is an Arduino, the same wiring for the motor (or in your case the CPU brushless motor), battery/power supply, and FET applies for the Netduino. For the FET in the diagram, I use a TIP120 Darlington transistor. I usually add a ~1K resistor in line with the PWM port as well. I've controlled small 12VDC motors and CPU fans with this wiring scheme.

Thank you for the diagram, do you by any chance have a schematic?

No sorry, that drawing is all I have.

I've been advised that I can create a "super-interrupt" pin on the Netduino by hacking the firmware. Please see quote from Chris Walker below:

...make that pin an FIQ-accelerated pin...and then use an FIQ handler in your code to count the number of pulses. Then you can easily create a "startcount" and "StopAndGetCount" managed code method to capture the values. FIQs will activate in less than one microsecond, will supercede the .NET MF runtime and...as long as they're quick...will not interfere with your code. We're using them for software PWM in an future update of the firmware, for instance.

Chris et. al,

How do I start with getting this set up? I downloaded the .Net MF Porting Kit and the Netduino Plus firmware, and I've copied the Netduino firmware into the Porting Kit directory. Now I need to know how to modify the firmware to get this operational.

Hi all, I am using some small LEDs for a project, and the goal is to create a small light fixture. I am trying to find a good material to use to diffuse the light from the LEDs. I have looked at theatrical gel filters, but these are flimsy and impermanent. Is there a way to use a piece of Lexan and coat it with diffusion material? If so, what diffusion material would work best? Or is there some kind of plastic like Lexan that already has a suitable diffusion coating? Any help is greatly appreciated! Thanks!

Hi, I have some values that I would like to graph. The x-axis will be Time, and the y-axis will be a sensor reading. My sensor readings are received every 1 second on the UART of a Netduino. Is there a graphing package out there that would fit nicely with the .Net Micro Framework? I would like to display the graph via a Windows form, or via a web page. Any suggestions?

I guess it doesn't really have to be .Net. I've decided to use this for now: XML/SWF Charts

A relay works. The problem is that the relay contacts are not going to last very long if I use this method. Can anyone think of any other way to do this?

Netduino touches my iPad.

See video action here: Netduino triggers iPad Drums. The ticking sound is not a metronome- it is the 9vdc relay I'm using to open and close the Ground.

I also notice that if I increase the speed, sometimes it misses hits on the touchscreen. Does anyone know why? Other than the anti-static foam, should I use other materials to get a more reliable contact?

Just so you know what I need to do:

• Connect anti-static foam directly to the display of an iPad (the anti-static foam is the stuff that IC's are normally mounted on when shipped)
• Connect a wire from Ground to the anti-static foam
• Trigger the Ground connection on and off

This makes the Netduino "touch" the iPad touchscreen. I've already tested this simple scenario and it works, but I have to physically touch the wire to Ground and remove it. I need some way of doing this with Netduino programming.

I have an iPad drums application, and my current idea is to make an automatic drum sample controller with the Netduino;

• Connect anti-static foam to each drum kit point on the iPad display
• Connect separate Grounds for each wire
• Trigger these wires individually so I can press each drum-kit item separately (high-hats, cymbals, bass drum, etc.)
• Record and play back the drum sample on the Netduino, sort of like one of those pianos that plays automatically.

This would also allow me to trigger the drum kit with other materials by using pressure sensors. Ultimately, I could use regular drum sticks on other materials to play the electronic drum kit on the iPad.

The problem I'm solving with this: the iPad display is small, and obviously I cannot smack real wooden drum sticks directly onto the iPad display, so I have to use my fingers to play the drum kit, which is not true to a real drum set, and it is cumbersome.

This would open up the ability to create a small electronic drum kit that could be played with real drum sticks. All the sounds are already there on the iPad; I just need to implement the electronic connections to "touch" the iPad display.

What do you think? Dumb idea? Cool idea? Useless idea?

Has anyone done anything like this before? Any tips?

Thanks!

Darrin, I tried OutputPort, and nothing. I tried TriStatePort, and it triggered a couple of times, but not reliably. I'm going to try a relay now. Thanks, Nick

With Netduino, how can I connect a single wire such that I can switch whether or not the wire is going to ground? Would I use a transistor? The wire does not need any voltage connection- it is just a grounded/un-grounded wire depending on whether I "switch" it between grounded or un-grounded. The other end of the wire is not connected to anything. Thanks!

Nice job, that's awesome!

Next thing I'd try would be a SSR (Solid state relay), something like this: https://www.jameco.c...ductId=1583068

Thanks again Darrin! My local shop doesn't carry SSR's, but they do have 5V Reed Relays, so while I'm waiting for the SSR's, I'll give them a try.

I just set up that FEZ code to run with the Netduino and the TLS235R, and Netduino still chokes on it after three reads. I also had to cover up the sensor with black cloth or else the Netduino failed immediately. Here are the readings I'm getting with the sensor completely covered:

Using an Interrupt
Reading 0
20400 Hz
221739.13043478262 uW/cm2
2650.3369113867698 lux (single)
163.81671308080081 lux (gauss)

Reading 1
20500 Hz
222826.08695652176 uW/cm2
2663.3287589916072 lux (single)
164.61973618413808 lux (gauss)

Reading 2
20400 Hz
221739.13043478262 uW/cm2
2650.3369113867698 lux (single)
163.81671308080081 lux (gauss)

Reading 3
3500 Hz
38043.478260869568 uW/cm2
454.71466616929877 lux (single)
28.105808616804058 lux (gauss)

Invalid frequency 0
Invalid frequency 0
Invalid frequency 0

I guess I am going to have to learn how to program another bare MCU and use that for my readings. It is really cool to watch the frequency change on my oscilloscope as the light levels change. The readings look nice and stable. And yes, I shined a really bright light on the sensor and watched the scope and it did go to one pulse every 2µs.

Hi NickDuino,

I'm just picking up on this thread now, but are you using InputPort to meeasure the time in managed code instead of using InterruptPort (which passes a fairly precise timestamp of the original event)?

Hi Chris,

I am using InterruptPort:

                // the pin is expected to interrupt on rising edges
                InterruptPort _dataOutInterruptPort = 
                    new InterruptPort(Pins.GPIO_PIN_D2, false,
                                       Port.ResistorMode.Disabled,
                                       Port.InterruptMode.InterruptEdgeHigh);

                // add an interrupt handler to the pin
                _dataOutInterruptPort.OnInterrupt += 
                    new NativeEventHandler(_dataOutInterruptPort_OnInterrupt);

And in the event handler _dataOutInterruptPort_OnInterrupt, I am simply counting the pulses with a long variable:

            private void _dataOutInterruptPort_OnInterrupt(uint port, uint state, DateTime time)
            {
                _pulseCount++;
            }

I'm then using the _pulsecount to determine the frequency and then using some additional math to get the irradiance. If I cover the TSL sensor with a black cloth, I do get a few readings from the Netduino, but after that, my Interrupt stops firing. If I shine a bright light on the TSL sensor, I never get any readings and the Netduino becomes "busy" and unresponsive to the IDE.

Perhaps there is too much code in my interrupt routine. I am going to write a real simple version that does not do any irradiance calculations and only prints a very limited amount to the Debug console. I will post the code to this thread later today.

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.

Can someone please speed up my Netduino? Does anyone have a Netduino Ultra I could borrow?