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#14186 Netduino Plus webserver Help

Posted by Veetrik on 10 June 2011 - 03:35 AM in Netduino Plus 2 (and Netduino Plus 1)


Thanks for your reply. I tried what you suggested, but the assembler didn't like the code.
After some investigation I found my problem in the program.cs.
There was no trap for a bad command sent from the browser.

Thanks again Gordon

That's great Gordan. by the way the could I sent you should have been:

string commandData = (rawData.Lenght >= 5) ? rawData.Substring(5, rawData.Length – 5) : "";

#13737 Netduino Plus webserver Help

Posted by Veetrik on 29 May 2011 - 01:16 PM in Netduino Plus 2 (and Netduino Plus 1)

It could be that rawData length is less then 5, you can try replacing: string commandData = rawData.Substring(5, rawData.Length – 5); with: string commandData = (rawData.Lenght >= 5) rawData.Substring(5, rawData.Length – 5) ? ""; However, the real issue is why is the rawData length is less than 5?

#13559 SkyNet

Posted by Veetrik on 23 May 2011 - 11:51 PM in Project Showcase

Very cool. Do you have a video of your project in action by any chance (YouTube)?

Thanks Chris, here's a screen shot:
Posted Image

and here's the video:

#13532 SkyNet

Posted by Veetrik on 22 May 2011 - 11:52 PM in Project Showcase

This SkyNet project uses a windows form to intercepts messages from a remote Skype connection
and passes them to the Netduino to control the position of a webcam.
It is similar to the SkyDuino project by Hari Wiguna for the Arduino.

After creating the Pan and Tilt project for the Netduino, I was using VNC to remotely to view my home (host) PC from my office (remote). I used a webcam viewer to see the webcam image and a web browser to send the commands on the host PC.
I thought it will would really nice to simplify this by viewing the image and controlling the webcam remotely using only one application. Skype seem like a good canidate for this.

To use this you will need two Skype accounts. The first account is for the host PC where Netduino is located.
Skype needs to be set up to automatically answer calls and to allow video calls.
The first time SkyNet is run, Skype will display 'SkyNet.exe wants to use Skype'. Select 'Allow Access' to proceed.

SkyNet is run on the host PC and it automatically starts Skype if it is not running.
It intercepts any chat messages received by Skype on the Host PC that are meant for the Netduino.
It then sends these commands to the Netduino via a socket connection. You can use the buttons on
the SkyNet form to send commands direcly to the Netduino for testing purposes. There is also
a checkbox available labeled 'Send To Netduino. You can uncheck this box if the Netduino is not connect and you wish to test SkyNet. There is also a box where you must enter the Netduino's IP address.

Code to send commands via socket to the Netduino Pan and Tilt application:

 public void SendCommand(string cmd)
           string header = "GET /PanTilt.htm?c=" + cmd + " HTTP/1.0\n"; 
           byte[] bytes = Encoding.ASCII.GetBytes(header.ToString());
           IPEndPoint remoteEP = new IPEndPoint(IPAddress.Parse(txtSkyNet.Text), 80);
           Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

On the Netduino you will need to run the Pan and Tilt which is a web server that uses these commands to control the orientation of the webcam mounted on pan and tilt servos.

On the remote PC you will use the second Skype account to make a video call to the first account.
You can use the Skype chat messaging system to send any of the following commands to the host PC:
u - up
d - down
l - left
r - right
c - center
skynet on - skynet will send commands to the Netduino
skynet off - skynet will not send commands (for debugging)

Attached Files

#13287 PanAndTilt

Posted by Veetrik on 14 May 2011 - 05:28 PM in Project Showcase

I have done some research on this and it looks like you can connect a servo directly to a pwm pin (see forum. I have not run into any problems by the original circuit, but as a precaution and since I'm familiar with TTL circuits I decided to add a 74LS04 chip as a buffer. This chip has six 'not' gates in it. Each gate inverts the single, so we need to use 2 gates for each line in order to get the correct signal out. I'm sure that there are many other ways of isolating the pins, but this is what I had available. Below is the breadboard diagram.
Posted Image

The thing about servos is that they use the +V pin for most of their current, the pulse pin seems to draw a small amount.

#13237 PanAndTilt

Posted by Veetrik on 13 May 2011 - 04:15 PM in Project Showcase

I'm not really a hardware person as you may have guess. So while this circuit did work, I think its advisable to look into adding drivers to protect the Netduino from the spikes. I will post an update when I have a safer circuit. Thanks Michel for the heads-up.

#13210 PanAndTilt

Posted by Veetrik on 13 May 2011 - 04:01 AM in Project Showcase

Pan And Tilt Project

This project is used to control a webcam's orientation from any web browser. I developed this so that I could monitor my back yard remotely (via VNC while at work) to see what animal(s) are eating my plants.

The project hardware consists of two servos for controlling the pan and tilt of a webcam by the Netdunio+. The Netduino accepts commands via the network and moves the appropriate servo using the Servo_API from Chris Seto. It uses pins 9 and 10 for the servos. Make sure that you hook the Netduino via the power jack to a 9v brick since the USB connector can not supplied the required current for the servos.

Posted Image

The commands are sent from any browser by using the Netduino+ IP address (e.c: followed by /PanTilt.htm as the URL. In my setup I use:

PanTilt.htm is a small HTML file that resides on the Netduino+ SD card. It displays arrows for controlling the camera position. When you press on the left arrow, the browser send a 'L' to the netduino via Javascript. The Netduino+ PantAndTilt application (which is a modification of my MicroServer application) server the page of the SD card and translate the commands, in this case into a 'left' command for the servo that controls the x-axis. There are commands for up, down, left, right and center.

I got the following Parts from SparkFun for this project:

Servo - Medium (ROB-10333)
Pan/Tilt Bracket (ROB-10335)

I believe SparkFun recommends the smaller servos for the bracket, but I was able use the
medium servos. You will need to play around with the servos, especially the one for the Y-axix (tilt) to make sure the alignment is straight one the application starts the servo's at the default 90 degrees.

Posted Image

Make sure you copy the contents of the web folder to the root directory of the SD card before testing the application. Good luck finding those animals!

Attached Files

#12947 MicroServer

Posted by Veetrik on 08 May 2011 - 02:46 PM in Project Showcase

Thanks Andy, I forgot to mention that I developed this using the Chrome Browser. I have updated it so that you should be able to use it with Firefox. Edit: It will work in IE but you need to combine the web client files for some reason. (mUpdate1.htm attached).

Attached Files

#12939 LCD question

Posted by Veetrik on 08 May 2011 - 03:30 AM in General Discussion

You might want to try connecting pin3 to 220 (Red Red, Brown) or 330 ohm resistor (Orange, Orange, Brown) to ground.

#12938 LCD question

Posted by Veetrik on 08 May 2011 - 03:28 AM in General Discussion

I have use the LCD on a Arduino without a potentiometer. But I used a 330 ohm (Orange, Orange Brown) on pin 3 connected to ground.

#12888 MicroServer

Posted by Veetrik on 06 May 2011 - 03:51 AM in Project Showcase

I finally got my hand on the N+ and this is my first app. It's a websever that serves pages off the micro SD card and gives the ability to maintain those pages directly from the browser client side. I wish to give thanks to Fred for his NetduinoPlusWebServer and Valyrie-MT for his Extensions.cs nd time. The server allows the for the maintenance of these pages via the client browser using a special page named mUpdate.htm This page is included in the web folder along with a few other support files. The mUpdate page displays a list of the files that are on the SD card and using javascript, allows to view the contents of any .htm, .js and .css files. These files can be loaded, modified and saved back to the SD card from the browser. This page also allows you to add, rename and delete pages or files on the SD card. In this way you can avoid having to take out the card to update the files. In order to use this application, first copy the contents of the web folder into the root directory of the SD card and put the card into the card slot. Then compile and run the MicroServer on the N+. Enter the url in your browser to access the page. In my case I use

Attached Files

#12126 Netduino Plus Sold Out

Posted by Veetrik on 15 April 2011 - 05:03 PM in Netduino Plus 2 (and Netduino Plus 1)

Are there any updates as to when the Plus will be available?

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