A motorized system idea controlled by means of a HP48G/GX came from Oscar Alejandro Ciro, at 1995, while we were 3rd semester of Electronics Engineering Pregrade. At that time, we received a short introduction to digital circuits, but this, combined with knowledge he got from some readings about, made possible to Alejandro to build a system
with 2 small DC motors, a phototransistor and a CMOS 4017 counter. Alejandro was able to control it by means of the infrared port included into his calculator, permitting him turn on, turn off, and select the spin direction of each motor.
System was very simple and full filled Alejandro's expectation.
Recently, at MICROPROCESSORS course, a projects's promotion to work on it as final requirement to pass the course was made. Then, we
decided to retake Alejandro's idea, and propose it as alternative project, to fill the requirement. It was accepted at once.
