This monstrosity of a module can be added to a robot to add five line follower sensors. Some of the soldering on this module is not pretty but it works great.

Features:

• 4 line-tracking sensors spaced out horizontally
• 1 centered tracking sensor optimized for crossing lines
• 1 pair of emitter-detector aimed forward for collision avoidance, with sensitivity adjust
• 1 micro-switch for use with mechanical bumpers
• LED Indicators on every sensor
• Active LS14 chip providing clean hysteresis on each sensor for jitter-free indication
• Detection distance of 0-4 cm (black and white line sensor) )
• Input voltage :3.0-5 .5 V
• digital output (Active HIGH for detected light object, bump switch)
• About 5.4 inches across 

Tutorial