line following robot without microcontroller

dear sir,
I have to build a line following robot of my own.
I had searched for many schematics in Google and i was not fully satisfied with them.
The main thing is the bot should not have an micro controller.
Please help me as soon as possible......
The specification of bot should be:
• The dimensions of the base of the bot should be 15cm x 15cm. There is no restriction on the height
• The potential difference between any 2 points in the circuit should not exceed 12V .
• It should not use ready-made kits like lego, but the use of geared motors is allowed.
• Image processing, remote controls etc SHOULD NOT be used.
Arena Specification:
• The finish will be indicated by a circle of radius 4cm.
• Discontinuities will be no longer than 2cms.
• Apart from these dead-ends, loops, acute angles and junctions may also present!


please help me i am in need of its schematic and also you are thanked very much if you can able to provide me an pcb layout.....

Thanking you,
regards ,
NM2007K.

You can build line follower robot using LDR as sensors. You basically require 2 LDRs, 2 white LEDs and some transistors (both npn and pnp)

Could any one describe this with a schematic.?

Some examples:

**broken link removed**
Build Your Own Transistor Based Mobile Line Follower Robot (LFR)

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**broken link removed**
non programmable Line Follower robot
Op-amp Line Follower Robot with PWM Motor Control « adafruit industries blog