Screaming Circuits: Designing for Movement

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Designing for Movement

What is the difference between electronics in a robot vs., say, a stationary temperature monitor and control device? For one, if the temperature controller goes haywire, you can pull it off the wall and stomp on it, while you might have to chase the robot (or be chased) to deactivate it if it's gone into world domination mode. More relevant, though, is vibration.

Fixed embedded electronics generally don't need to worry about vibration induced reliability issues. Mobile robots, however, do. Unsecured connectors can work their way loose. Bolts can back off. wires can brush against stuff. A lot of practices that don't cause problems in a fixed installation can bite in a mobile setting.

For example; a simple board to board ribbon cable. On the left, is a common friction-retention cable connector. Fine for a development board, but not for an environment subject to vibration. Instead, use a mechanically captive connector, as shown on the right.

Connectors

Free hanging cables are also a "no" for mobile devices. Cables hanging loose can get caught on edges, or tall or hot components. That can lead to worn or melted insulation and shorts. Instead, use cable ties, insulating grommets, and careful routing.

There are plenty of other considerations, but these are two of the biggest traps to avoid when movement is called for.

Duane Benson
Klaatu barada nikto. Translation: "Spaceman says what"

Comments

What exactly is the second connector?

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