Page 128 - Anatomy of a Robot

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COMPUTER HARDWARE 113
Shock
Glass displays will crack once G forces get too high. It’s very easy to
break LCDs; people break their portable PC screens all the time.
Temperature LCDs have a very limited temperature range and will become
unreadable outside that temperature range. Look for other display types if the
robot needs to function over a wide temperature range.
Longevity The backlighting of LCDs can wear out over time, making them
dimmer and nonuniform. This can happen if the LCD contains bulbs, which will
suffer from metal migration over time. Look for LCDs that have backlighting
using other technologies and check the MTBF specifications.
Power The LCD backlighting can take quite a bit of energy. Further, the soft-
ware to control the energy expenditure can be complex to write.
Electromagnetic interference (EMI) When considered in terms of electro-
magnetic shield integrity, LCD screens are just massive holes in the package of
the robot. This makes it very hard to keep radiation from leaving or entering the
robot.

Process for Choosing a

Robot’s Computer Hardware

At some point, we’ll be faced with the task of picking the actual computer to put inside
the robot. This is a task that requires experience and should be approached in a sys-
tematic way. That said, almost everyone does this a different way, so have patience with
differing opinions. And try to bear in mind that a diverse gene pool actually is a good
idea!
The first thing to consider is getting some help. Just as advisors can be of consider-
able assistance in the planning phases of a project, so too can they be of value in the
early High-Level Design (HLD) phase. The best advisors to approach are experienced
engineers who have done it all before. They can often see clear solutions among the
many options available to the project.
Barring the discovery of an immediate solution for the needs of the project, it makes
sense to list the viable candidates that will be considered. Whether it makes sense to
build or buy a computer for the robot, the end result will still be the same. The robot
will have a computer board (or boards) inside it, and the boards will contain a proces-
sor chip. In listing the candidates, it makes sense to list them all as processors.
Magazines list processor chips in articles that are updated at least yearly.