Mechanical Design – Some Thoughts
It's way, way too early in the process to start thinking about some of the design details. I haven't even opened all the kit packages yet - I've been too busy cleaning up and organizing my home office space. That should be finished in the next few days, and then I can start familarizing myself with the various components and assemblies. In all probability it will be weeks before I actually have Maxwell to the point that he can start to take his first steps. My best guess is that it will be close to Christmas when I start to get seriously involved with the issue of sensing the outside world - plenty of time.
Still, as I think about what Maxwell will eventually look like and what he will need in the way of sensors and displays, I know that my design priorities should include factors like:
- design flexibility: design flexibility in from the beginning to avoid massive redesign and lost time later in the process
- adjustability: sensor angles and component positioning may need to be changed unexpectedly
- solid, stable: needs to withstand being transported and handled (manhandled?) without needed extensive readjustment or alignment
- clean, neat, well packaged: professional looking design; no rats nests; clean lines; nothing I would be ashamed to post a photo of on the internet
For example, on the bus I was thinking about sensor mounting, LED and/or IR sensors specifically since I think that Maxwell will need a few no matter what I want him to eventually do. I've seen a lot of different approaches for mounting on various micromouse sites. While all of them seem functional, a lot of them look very juryrigged and fragile. I can easily imagine how difficult it is for them to produce consistent, repeatable results. Of course, some juryrigging is always necessary when you prototype anything.
Some of them involve using hot melt glue, bending sheet metal brackets, or the proverbial bailing wire and bubble gum. The bent sheet metal poses some issues. If the metal is soft enough to work with, it's also soft enough to bend when you don't want it too - and always at the worst possible time. If it's stiffer, then it becomes hard to adjust to align the sensors.
One approach that really appeals to me, at least at this point in the game, is to mount the sensors as modules on a length of threaded rod stock. Each module would include an emitter and a sensor. The relative weight of the sensors is small, and as long as the rod length is fairly short it should be stiff enough to hold them in position without much vibration or misalignment. The sensor positioning can be easily varied along the length of the rod, and it's vertical angle relative to the horizon should also be easy to adjust. At least that's my theory at this point. We'll see how it plays out.
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