This DIY robot kit will follow a black line on a light coloured background.

This is a great introduction to electronics and soldering. You can create track using black electrical tape onto a lighter background. 

The sensors at the front of the robot detect the change in light and control two motors to follow the line.

The circuit uses two comparator circuits and two light dependent resistor sensors to measure the reflected light. Here is a video of one in action:

This kit is fully analogue and requires no programming.

The following parts are included in this kit:

Full instructions are available here.

Please find the "Soldering is Easy" guide available here.

Please note: This kit is reasonably fiddly to built and will take in the region of 1-2 hours. It is suitable for ages 12+ or with adult guidance. This kit requires adult supervision in both construction and use.