I don't have the details, but if you intend to build it yourself, perhaps I may help.
How big your robot should be? What is its weight? From that, you can compute how strong your motor should be. For small bot, they usually use 6VDC motor at 200mA.
To control small bot, using TA7288P is enough. It's very cheap and small. You can use 2 TA7288P for 2 motors. It's a one and a half H bridges.
I have the .max file only of TA7288P with 89c51. I lost the schemes file, you have to rebuild yourself. email meeh at :
doanhiep@swissinfo.org, I'll send it to you.
For the sensors, I used red leds, but I lost the data. After many time do experiments, I found that red leds are better than IR led. You can try with it. You can build it yourself.
It's the useful site to show how to compute the PID control for the line following robot, and they show where we should put the sensors on the bot.
**broken link removed** (role down the frame and look for line following 1995)
And examples come here
**broken link removed**
https://www.robotroom.com/Sandwich.html