A Miniboard is highly successful at implementing simple robots. The most attractive feature of the Miniboard is that it is cheap. If you compare the Miniboard to a 6270 board, a Rug warrior board, or an F11 board (ask about them in comp.robotics) the Miniboard will be much less expensive and lack a few resources. Mostly the Miniboard lacks memory. The 2K byte limit on the code size and 256 byte limit on the data size is very tight if you use a compiler. If you are using an assembler, the space is fair; not generous, but not tight either. The number of sensor input is also a bit limiting as compared to other controller boards (8 analog, 8 digital and 8 timers/counters). But for simple robots, the Miniboard's inputs more than suffice. For example, a line following program would use 4 analog ports, a wall following program would use 3 or 4 digital ports, shaft encoders would use one event counter each, an object detection program might use one analog port or one digital port. All of the above could be implemented simultaneously on a Miniboard. The motor outputs are also very limiting. A Miniboard can drive 4 DC motors or 2 ea. 4wire stepper motors. A robot drive system can be easily implemented in 2 motors. But a robot will usually need more motors and/or actuators to implement functions other than mobility (like picking up or dropping off an object).
A Miniboard is highly instructive for an introduction to embedded systems design or digital control applications. The 6811 chip on the Miniboard is only interfaced to two other chips, the motor drivers. That is, all the memory, A/D systems, input/output systems and timers/counter are on the 6811 chip itself. The simplicity of a Miniboard is non-conducive to learning about microprocessor interfacing, but it is very conducive to learning about the functionality of MCUs and how to sense/control the environment with them. A Miniboard programmer will come to comprehend digital control concepts like sampling/converting of analog signals, sensor interfacing, the control decision making process, under/over correcting, latency times involved in ISRs, and closed loop feedback systems. Building a robot is a fun context in which to do a lot of very practical learning.
ieeecs@hal.elee.calpoly.edu
Back to Table of Contents