Need help with my PC controlled Wireless Surveillance Robot

[agentmango]

Hi guys, I am a newbie here. By the way I'm Allen from Philippines and I would like to ask for assistance to experts in this forum for this project.
I would like to create a PC controlled wireless surveillance robot. And I am having problem with the materials.

Here are my problems.

- The ICs which I need (SM6136 and SM6135) are not available in my country and I cannot afford to buy abroad. So I want to find an alternative for them. The ICs mention were actually the ones who will control the movement of the vehicle.

- What specific type of wireless surveillance camera should I buy. It's too expensive so I don't want to make a mistake on this one.

Any suggestions from you guys would be very much appreciated. Anyways, I know about RC's but I am not planning to use them on my surveillance robot.

[waltr]

I would look for another chip that has the same or equivalent functions as the SM6136 and SM6135.

[Soeren]

Hi,

- The ICs which I need (SM6136 and SM6135) [...] I now about RC's but I am not planning to use them on my surveillance robot.

SM6135/6 is a (very simple) R/C encoder/decoder chip-set.

If you're contend with non-proportional (i.e. binary on/off) channels (as the SM-chips give), it would probably be cheaper to just get an R/C car at a local flea market or similar and gut it for the electronics.

[agentmango]

I have search for alternative chips but I can't find some. I was thinking to do the robot wired. But my concept of wireless will be gone. If I will use the RC's transmitter and receiver, I want it to be interfaced with the computer's arrow keys. For example, instead of holding the joystick and moving them in desired direction, I would press arrow keys of the keyboard. But how will I do that? hmmmmm....I have already ruined my gantt chart ahahaha..

[rbtying]

Use a microcontroller to replace the functionality of the missing IC's: it is a simple matter on a microcontroller to both encode and decode standard RC "PWM" (which is really PPM).  You can then connect the system like this:

PC <-> USB-UART bridge <-> microcontroller -> RC transmitter -> RC Receiver -> microcontroller #2 -> other functionality.

The RC transmitter/receiver could also be replaced with any wireless UART solution, most notably the XBee line of RF modules.

[agentmango]

@rbtying - hmmm..Sir could you explain this part further?

PC <-> USB-UART bridge <-> microcontroller -> RC transmitter -> RC Receiver -> microcontroller #2 -> other functionality.

I got the idea but not much. As of now I have a micro controller on my main board. That is where I will inject the program.
What about the "  microcontroller -> RC transmitter -> RC Receiver -> microcontroller #2 "

Does that mean I have to use 3 microcontrollers? and each have different program?

I fell sorry for being newb..

[rbtying]

You will need a total of 2 - if you already have one on your bot, that will suffice for one of them.  The other will be needed to convert commands from the PC into RC signals.

The RC "PWM" protocol is usually implemented as a pulse at 50Hz, with a pulse width between 1000ms and 2000ms.  The linear scale in between corresponds to the linear movement of the joystick on the RC transmitter. 

To send the signals, you will probably find it easiest to use the "trainer" connection on your transmitter and figure out the necessary protocol to emulate another controller (this part is transmitter-dependent, so I can't help much). 

To receive, you simply hook the signal pins from the receiver into GPIO, and time the pulse.  You can then use the value as an input.

Here's a link that might help: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1193927390

[agentmango]

@rbtying - thanks for the help..I am now trying to do as what you've said. I am actually making two PC controlled surveillance robot now.

1 . The one that I've been looking for help lately and then I've come with this new idea.

 2. Instead of two Transmitter and Receiver, I will use only one. How? I'll use the transmitter and receiver of the wireless camera that I will buy. So that would be one RX/TX for the vehicle and the camera. Do you think it would be possible?

[rbtying]

You won't be able to access that Rx/Tx pipe, unless you're thinking of some camera I don't know about.  The normal method for wireless surveillance is to use XBee wireless or a bluetooth<->UART bridge, both of which simply simulate a UART and make your life much easier.  Trying to minimize connections won't help you - the time it would take to get it to work would be more than the amount of extra money you spend.