Princess, showing off those fine sonars, chipper furby, and feature-laden 555.
Princess, flaunting a quality vanity plate, breadboarded voice chip, and very big power transistors. (Speaker not installed yet.)
Description
Princess is a remote-control car with an MPC555 and a voice-recorder chip (ISD2590). It uses two sonars for navigation. Pushing a pushbutton at any point lets the user input five voice samples. Otherwise Princess navigates the hallways of the EECS building, spewing out random voice samples. The furby makes it intimidating so people will listen.
Components
We used the CodeWarrior development environment to program the MPC555.
The voice recorder chip was controlled via the 555's general purpose I/O registers.
An LED display for sample-recording indication was controlled using PWM for fade-in effects.
The two sonars were given offset PWM signals. Their echo_out outputs were tied to two TPU pulse-accumulation module's pins.
The steering servo was controled by a PWM output.
The pushbutton was tied to an IRQ (edge-triggered).
The Furby and the DC motor were controlled by general purpose I/O registers. Specifically, the pin for the motor controlled a mosfet power transistor (which gave princess some speed, when she felt like it.
Most Difficult Issues
Time
CodeWarrior
Defective old cabling found in the lab
Time
Making the propaganda loud enough
Finding a good steering algorithm (to deal with the instability of sonar readings yet still be real-time enough to not run into things).
