Tip120/Tip122 Darlington Switching Circuit

It depends on how the robot would react to only one side of it's drive moving. Some will circle around but others struggle to move.

I would spend the money on a H-Bridge to be honest, a TIP isn't really the right way to control a motor. You can pick up the TB6612FNG Motor Controller for pretty cheap, it's what I use in my robot. Just be wary of the maximum current it can take. If the motors are high power you will want something along the lines of the Sabertooth.

my motors are mini toy dc motors and my robot can turn right and left really eaisly i just need a code to do that if there is such code it would help me or is there a circuit board that i can make at home if not i just need a code thanks

PWM on one side for however long it takes for it to do a 180 degree turn.

PWM(D0,100)

You may (however I do not know) be able to use the 4 wire HBridge movement panel. Left() and Right() set forward on the one side and reverse on the other, but with no reverse it should still turn. You just wouldn't have Trigger B and would need to set Left and Right Trigger B to unused ports. I have not tried that though.

I still wouldn't suggest running motors from a TIP though but it's your call. Just make sure you make the circuit right and include the diode to save yourself from breaking the EZB.

i decided buying 2.5 Amp Motor Controller from ebay eventually sorry to bother you