Salvaged parts for my first robot....

[Valkrist]

I've been collecting things for a little while to construct my first robot. I have an incredibly tight budget, so everything I have was free, and hopefully it can stay that way. First, the basic design of my robot is very similar to the $50 robot. It has a differential drive system with two wheels, and it has a low friction castor. I don't have any questions at all about the design, I'm more concerned with how I can make my parts work together (I'll explain more in a moment) and get the most out of the inputs and outputs I have available.
Most of the parts I have I took out of a Wowwee! Roboreptile. So that includes 5 motors, 3 IR LEDs, 2 IR recievers (not sure on terminology, black domes) A sensor that looks like an LED but I think might be a type of photo resistor. I saw someone online somewhere refer to it as a CDS sensor. I have two sonic sensors...um, I think that's it from the Roboreptile. The board on it is apparently not re-programmable. For my processing I have a Mindstorms Intelligent Brick. It has 3 motor outs and 4 sensor ins. I don't have any other mindstorms parts though. The brick was given to me for this project.
The problems I have are A) I don't know how to rig my sensors into those NXY slots. I found a diagram of the plugs on the NXT Wiki, but I don't know what's what on my sensors. B) I think I'll need all four sensor inputs for my IR object avoidance, which doesn't allow me to use the sonic sensors to have it track noise. Can rangefinding be done with one IR LED and one receiver?
Sorry for the length of the post, I wanted to provide as much information as I could in the first post to get quicker answers. Thanks in advance for any thought put into this with me.

[Soeren]

Hi,

[...] A sensor that looks like an LED but I think might be a type of photo resistor. I saw someone online somewhere refer to it as a CDS sensor.

CDS = Cadmium Disulphide Sensor = LDR = Light Dependant Resistor. But they don't look like LEDs. Might be a photo diode/transistor.

Apart from that, building with a LEGO brick controller and a budget of zero is something of a challenge and if you're up to it, you should be able to find the pinouts etc. needed - if that's not the case, prepare for a capital infusion (newspaper delivery, dog walking, car washing etc. might help here) and the first parameter I'd adjust is the controller - just a few $$ will give you access to something useable (which the LEGO really isn't).

[GWER57]

If your willing to shell out ~$25 you could get the NXT dev kit from mindsensors. Check the schematics that lego gives on their site for info on how to use the sensors. And if your motors have a low enough current draw you can connect those directly.

Just do some snooping on their site and see what you can find in the way of technical info .