Veetrik

Veetrik,

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) : "";

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?

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

Thanks Chris, here's a screen shot:



and here's the video:
http://www.youtube.com/watch?v=mx-WD_sVqfE

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.


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.

http://www.youtube.com/watch?v=W1WQ3EzciOA

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.