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There have been 66 items by Nobby (Search limited from 09-July 24)
#30581 Netduino Reset Button Issues
Posted by
Nobby
on 12 June 2012 - 08:05 AM
in
Netduino Plus 2 (and Netduino Plus 1)
#32851 Ping works for 2min that quits working (4.2 RC5)
Posted by
Nobby
on 28 July 2012 - 01:51 PM
in
Netduino Plus 2 (and Netduino Plus 1)
#32970 Ping works for 2min that quits working (4.2 RC5)
Posted by
Nobby
on 01 August 2012 - 07:24 AM
in
Netduino Plus 2 (and Netduino Plus 1)
I hadn't up until you suggested it. I thought I could power it with simply the USB connection. Now that I have added the external power source, the board seems to behaving as expected.
Is there a 'theory of operation' or any documentation around how the systems works together? I seems like the blue led on the board corresponds to the time when the bootloader is available vs when the CLR is running.
Thank you for the suggestion!
According to the Netduino schematic, the USB socket is essentially electrically and logically isolated from the button and LED. My best guess is that you possibly have the Netduino plugged into a standard USB port and there is some sort of power management policy under windows or possibly your BIOS that is cutting power to the Netduino for being idle or some other reason.
Although, I've never come across this problem before except with some models of USB powered hard disc drives. I also connect my Netduino to my PC via a self-powered USB hub and I also have no power management enabled under windows except for turning my screen off after 10 minutes(Performance power profile with hibernation/sleep disabled).
#37294 Yet another diagnostic question
Posted by
Nobby
on 16 October 2012 - 11:43 PM
in
General Discussion
#32850 Take a dirty picture for me
Posted by
Nobby
on 28 July 2012 - 01:48 PM
in
Netduino Plus 2 (and Netduino Plus 1)
sorry, the topic is not going to be that interesting.
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I've got my NP hooked up to a serial camera and i want to take a pic and then push it on a webserver.
By the looks of it im getting a outofmemory exception. Is there any efficient way of do this with out using lots of memory?
Is the camera data compressed into JPEG or is it full-frame RGB/YUV pixel data? Either way, image resolution of most cameras these days will exceed the runtime RAM of the Netduino. To test the full functionality of your project(i.e. take pic, get data from camera, post to webserver), try and set the camera to its lowest resolution if possible.
If you don't have those kind of configuration options for your camera, you'll have to go the whole-hog from the beggining. Adopt a block-data processing model. Take the picture and read small amounts of data from the camera at a time. You'll have to send or store(SD card) that data then leave it for the GC to pick up or force the GC to free the memory. Read the next block of data, rinse and repeat.
Are you using a POST method to a web URL? If so, you can define the Content-Length HTTP header property before you stream the data to the webserver(only if you know the datasize of the image before-hand). This will allow you to block process the data, as long as you don't exceed the webserver's timeout. If you can't determine the size of the pic data before you read it from the camera, stream it to a file on an SD card in the Netduino and then read the file-size.
Good luck
#35267 Interfacing netduino with an alarm clock
Posted by
Nobby
on 15 September 2012 - 08:22 AM
in
General Discussion
#38284 Tenda 3G611R+ 3G router issues
Posted by
Nobby
on 31 October 2012 - 09:19 AM
in
Netduino Plus 2 (and Netduino Plus 1)
#31948 Any plans for have ParameterizedThreadStart available in the MF?
Posted by
Nobby
on 13 July 2012 - 03:41 AM
in
General Discussion
Good day everyone.
Any plans to have ParameterizedThreadStart available in the MF?
Thanks
You can use lambda expressions in conjunction with the standard ThreadStart class. It allows you to have type-safe targets as well.
class MyClass { Thread myThread = null; public MyClass() { this.myThread = new Thread(() => MyClass.threadFunc(this)); this.myThread.Start(); } private static void threadFunc(MyClass myClassObject) { //do stuff here } }
Target delegate doesn't have to be static either
#32652 SD card trouble
Posted by
Nobby
on 25 July 2012 - 08:20 AM
in
Netduino Plus 2 (and Netduino Plus 1)
- The file test.txt already exists on the SD card
- The name of the root directory isn't \SD\
It may seem long-winded but I always query
VolumeInfo[] drives = VolumeInfo.GetVolumes();
It serves to ensure there is an SD card inserted(there are also other ways to check this). The objects also indicate the name of the root directory.
I haven't looked up the reference to Directory.GetCurrentDirectory for Micro Framework. It's standard usage is to return the current working directory which only applies to application domains running normal .Net Framework applications on a PC etc. Since the Netduino executes code from Flash rather than a virtualised application domain run from media, it doesn't use working directories.
#32651 start multi-projetc's on netduino
Posted by
Nobby
on 25 July 2012 - 08:04 AM
in
Netduino Plus 2 (and Netduino Plus 1)
- Add a new project to solution
- Choose "Class Library" instead of "Netduino Plus Application" under Visual C# -> Micro Framework. This what you mean by DLL?
- Write the code in your class library
- Go to your Netduino Plus application project, choose to add a reference
- In the projects tab, choose your new class library as the reference
- You can now use your class library in the Netduino Plus application!!
#32675 Does Netduino Software software getting cleared over time?
Posted by
Nobby
on 26 July 2012 - 12:21 AM
in
General Discussion
#34469 Probelms In Sockets??
Posted by
Nobby
on 30 August 2012 - 10:28 PM
in
Netduino Plus 2 (and Netduino Plus 1)
- You close the socket
- Have a ReadTimeout value set on the socket
Either way, an exception will be thrown on the PC application. Make the buffer smaller to match the length of the data or provide an amount to read. In your case, the PC application will try to read 1000 bytes all-up.
On the Netduino side of things, I never simply use Socket.Send(). I always tell it was data range to use from the array so that I know I have full control over safe execution. This doesn't mean that the Netduino exception is being caused by this.
#37413 PCF8574N inverted outputs?
Posted by
Nobby
on 19 October 2012 - 06:55 AM
in
General Discussion

#32491 Multiple questions from someone thinking about picking up a netduino
Posted by
Nobby
on 23 July 2012 - 01:50 AM
in
General Discussion
#32163 Multiple questions from someone thinking about picking up a netduino
Posted by
Nobby
on 18 July 2012 - 02:21 AM
in
General Discussion
#34082 InterruptPort, NativeEventHandler & data1
Posted by
Nobby
on 23 August 2012 - 03:25 AM
in
General Discussion
#34083 InterruptPort, NativeEventHandler & data1
Posted by
Nobby
on 23 August 2012 - 03:39 AM
in
General Discussion
#32090 GPS shield odd results. Novice user.
Posted by
Nobby
on 17 July 2012 - 06:30 AM
in
Netduino Plus 2 (and Netduino Plus 1)
Sometimes the data can contain characters which are non punctuation, letters, numbers etc because certain bytes are acutally bit-fields of configuration and satelite data. String constructors might return NULL based on these non-alpha numeric characters. Instead, make a string, use a for/foreach loop and append each byte onto the string but cast it as a char.
change this
Debug.Print(new string(Encoding.UTF8.GetChars(buffer)));
to this
string dataString = ""; foreach(byte b in buffer) dataString+=(char)b; Debug.Print(dataString);
Good luck
#32681 Analog Pins for drive LEDs
Posted by
Nobby
on 26 July 2012 - 04:04 AM
in
Netduino Plus 2 (and Netduino Plus 1)
Hi Guys,
As I have exhausted all the Digital Pins for all my pulse counter and communication, now only left with the Analog pins untouched. May I know is there any way I can use the Analog pins for driving a LED (for machine status) purpose? also can it be configure to use to detect button press input?
Thanks in advance.
I have recently used a few of the analog pins for similar reasons as yours. I can confirm you can use them as TTL output pins and almost certainly as TTL inputs.
Just ensure the maximum forward current through each LED doesn't exceed 25mA(maximum pin current).
#38170 Low Latency Wireless Comms
Posted by
Nobby
on 29 October 2012 - 10:39 AM
in
General Discussion
#38173 Out of Memory - Debug.GC(true) says I'm not?!
Posted by
Nobby
on 29 October 2012 - 11:21 AM
in
Netduino Plus 2 (and Netduino Plus 1)
#38804 Netduino Stops when switching relay through transistor
Posted by
Nobby
on 09 November 2012 - 01:03 AM
in
General Discussion
Hi!
Thanks for help! Finally I found the problem with Nobby's tip. I changed the base resistance from 1k to 6k and it works now in every variations. However I don't understant totally because I think that the relay's inner resistance limits the current to 70mA. So I don't know why is it a problem if the transistor's gain is too high. By the way I use a BC327-40. As I checked the datasheets its gain is above 250.
Now it works, so thank you!
Awesome work!!
250 gain is pretty high for low power circuits and 6k would be a lot better than 47k in your case. When you design in the future, transistor parameters are important. High gain will usually mean a higher forward-bias base current and larger voltage drop from base to emitter which means you'll choose a smaller base resistance etc.
As for the relay, devices like that don't have the capability to regulate/limit current unless they switch off from over-current(built in protection) so it's important to do power calculations for your transistor circuits. The current in simple circuits like this are always determined by the voltage level of your power source (i.e. 5V) and the total resistance/impedance of the circuit path the current is travelling along. If you follow those fundamental rules in design then your systems will function predictably and safely.
#38532 Netduino Stops when switching relay through transistor
Posted by
Nobby
on 05 November 2012 - 06:09 AM
in
General Discussion
#32581 Passing Servo's to another thread.
Posted by
Nobby
on 24 July 2012 - 12:03 AM
in
Netduino Plus 2 (and Netduino Plus 1)
#38211 Wireless contact switch
Posted by
Nobby
on 30 October 2012 - 12:31 AM
in
General Discussion
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