The idea is making Line Follower Robot by using LDR

LDR defines light resistivity and differentiate between white and black (TM1).

Voltage drop between LDR and R1 is used to trigger base of transistor (2N222) to allow motor movement on jumpers (J1, J2)

,When LDR< R3 motor will switch on ( white space)

When LDR> R3 motor will be off ( black lines)

JP4 for power (+12V)
JP3for Ground

Using two circuits with two motors will be enough for making Line follower Robot

Step 1: Board Layout

On eagle software after drawing the schematics, open board layout, add routes to the components and board border

Step 2: PNG Files

Extract PNG file for bottom layer, pads, dimensions and vias ... mirror the image

Extract another PNG file for only pads, dimensions and vias .... mirror image then switch white and black colors

Now the files are ready to be manufacutred on Modela Machine then Soldered