Pololu Motor Controller Daisy Chains

[kresty]

Did you have to use the Pololu software to change the input type from serial/USB to RC on each of the SMCs?  Also, the diagram you provide states, "Arduino and SMC must share signal ground", what does that mean? Do the SMC's need to be ground to the Arduino or can they all be ground to the battery?

Please let me know

Yes, the Pololu software has to be used to configure the SMCs -- it's also worth setting the limits at that time.

Short answer to grounds:  All the grounds can be connected to the battery - terminal.

All I meant by sharing "signal ground" is that the signal wire (Rx/Tx) is in reference to some common voltage (ground in this case).  If they have different grounds (maybe you used a big 12V battery for the motor controllers and a 5V battery for the arduino), then those grounds have to be connected (common).  Otherwise the tx/rx signals will appear to "float" to one or the other side and basically not work.

The Arduino's Vcc could also go to the +12V (depending on which arduino you're using and if it has a built-in regulator).  Alternatively, the Simple Motor Controllers have a regulator and you can steal a little of their 5V to power the Arduino (but if you do that, then ONLY CONNECT ONE SMC 12V to the Arduino - you don't want their regulators to fight eachother!  Also don't do that if your Arduino is getting power from somewhere else!)  

Similarly the receiver has to get power from somewhere - probably one of the SMC's because it's already got a jumper going there - but you don't want to try to power it from ALL of the simple motor controllers, only connect it's 5V line on one SMC.  (ground probably needs to go to both? -- though that makes me wonder about ground loops, though that's probably not a problem in most implementations)  

Hope that helps.