Servo - June 2011

Make Your Robot’s Wires Extinct

by Fred Eady

Way back when dinosaurs roamed the hills of Tennessee, I was learning how to wire up tube and transistor circuits. There was no such thing as ExpressPCB. In fact, there was no such thing as a BBS or the Internet. Only the professional magazine writers of the day with access to a printed circuit board house could muster an article that included a project mounted on a fancy copper clad piece of fiberglass. Meanwhile, I continued to string wire between circuit points and electrically seal them with solder.

Years passed. The dinosaurs died. Dial-up BBS sites gave way to the Internet and professional printed circuit board houses reached out to folks like you and me. Telephones lost their wires and personal computer Ethernet cables disappeared. I’ll bet you’re still wired to that microcontroller that you’re going to use to control that rolling aluminum slab you call a robot. Read on and I’ll show you how to lose the wires.

www.servomagazine.com/index.php?/magazine/article/june2011_Eady

A New 8051-based Powerhouse

Before we put on our pointy hats and discuss the radios, I’m going to introduce you to the SPECTRUM ACE 2a — a really neat, self-contained computing platform from I2I Controls. ACE is short for Advanced Control Environment. The SPECTRUM ACE 2a single board computer is going to be right down your alley. As a robot

FIGURE 1. Some things work so very well that they never need to change. This is the same circuit I cut my 8048 and 8051 teeth on 25 or so years ago.

A15

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54 SERVO 06.2011

DS89C450

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head, you are ALL about control, and that’s what the SPECTRUM ACE 2a is designed to do. The ACE 2a is the largest microcontroller platform in the SPECTRUM ACE family. The ACE 2a is based on the Dallas Semiconductor DS89C450 ultra high speed Flash microcontroller. If you roamed with the dinosaurs, you know all about the 8051 microcontroller and its variants. The DS89C450 microcontroller does in one clock cycle what the T-Rex 8051 does in 12 clock cycles. Remember the 8751? The 8751 had EPROM under quartz that could be electrically programmed and erased via a UV lamp. If you had a few days between spins, you could set your programmed 8751 in the sunlight and eventually somewhat erase the program memory area. I used to keep opaque tabs to cover the quartz window to prevent accidental erasure of my 8751 code that took days (and sometimes weeks) to perfect. Not so with the DS89C450 microcontroller. Like just about every modern microcontroller, the DS89C450 keeps your magic potion safe in 32K of eight-bit Flash. The DS89C450 doesn’t stray far from the things that make it a true