Strain Relief and Shorts

IMG_2194Yesterday, just as I was about to leave work, one of my coworkers dropped by to see what I was doing and thought it would be fun to be experimented upon. Cool.

I fired up the system, created a new setup file and ran the test. Everything ran perfectly, and I got more good results. When I cam in this morning though, the rig was pretty banged up. A wiring harness that had been fine for me working out bugs was nowhere near robust enough to run even one person through a suite of tasks. It’s the Law of Enemy Action.

You’ve heard of Murphy’s Law (Everything that can go wrong, will). The Law of Enemy action is similar: “People will use your product as if they are trying to destroy it”. In a previous life I designed fitness equipment and it was jaw dropping to see the amount of damage a customer could inflict on a product. Simply stated – you need to overdesign and overbuild if at all possible.

With that in mind, I pulled all the hardware off the Phantom and started over. New, lighter, more flexible wire. strain relieved connections. Breakaway connections. The works.

When it was done, I fired it up and started to test. Sensors – check. Actuators – check. Yay! And then the right pressure sensor started to misbehave. It was kind of beat up, so it made sense to replace it. But when I went to test, the new sensor was misbehaving in the same way. And it seemed to be related to turning on the vibro-acoustic actuators.

Time to open the box up and poke around. Nope – everything looked good. Maybe the connector? Aha! My new more flexible cable was stranded rather than solid. And a few strands from one of the wires was touching the right sensor connection.

So I pulled everything apart and replaced the cable that went into the connection with 22 gauge solid wired which then connected to my stranded cable. All fixed.And an example that even though Murphy’s Law is bad enough, you should always be prepared for Enemy Action.

 

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