We are building this robot to learn how to work with FPGAs work and also to explore advanced features of line followers, such as:
- High resolution sensor - 32bit IR detector array
- PID control algorithm
- Web interface for config and monitoring
- Position tracking with rotary encoders on wheels
- Motor current sensing
It's possible to make a line follower with just 2 photosensors. Such configurations aren't very precise and thus not suitable for high speed. That's why people typically use 4 - 8 sensors.
That's not enough!
The bigger the better! To get even better precision and smooth control, we made an array with 32 infrared reflective sensors. FPGAs have a ton of available inputs, so we can afford 32 parallel channels.
To clean up the signal from our KU163 sensors, we used four 8-channel digital buffers with hysteresis.
The drawback of this approach is that the sensitivity is set by the resistors in series with the phototransistors, which are not easily adjustable.