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Studying for a test? Prepare with these 5 lessons on Home-made robots.
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--different components here for our Bit-zee Bot. And we're going to take our tap light apart and see if we can use the structure, the outer ring of the tap light as a way of supporting or creating a structure for our Bit-zee Bot. So we're taking all the screws out, and we're going to take the tap light apart. And you can see the base of it has a lot of features on it. Screw features, and battery holder features, and so we're going to see if we can use the material-- I'm just lining up the motor see if it fits there with the ring-- and then we're going to see if we can use the material that's flat, like this sheet of lexan to support the internal components. The original piece there has all these raised components so they're not quite in the right space. So we're going to use the original piece as a template. And we're going to just trace it with a permanent marker. And the lexan has a covering on the outside, so it's no problem to trace on that. And we're using lexan because it's a very durable plastic. It machines easily, you can drill holes through it, and it also looks good. It's clear and very strong. And so this is called a rotozip bit. It's a bit that allows you cut sideways in a material. And the Dremel comes with this fitting that you can put on. You have to take the collar on the top off. And then once you've removed that collar, you can put this fitting on, and this fitting will allow you to basically use the Dremel like a router. And you can use it to cut material apart. And so we're going to adjust the depth of that so that only about a quarter of an inch of the bit is sticking through. OK, so now that we have our housing connected to the Dremel and it's all tightly fastened, and we have it adjusted to the right depth, we're going to clamp our lexan to the edge of the table. And once we get the lexan clamped-- and we're going to only allow about an inch of the lexan to overhang the table, so that when we make the cut, the lexan doesn't flex too much. If much more than an inch hangs out, it'll flex a lot. It's important to only do this if you have a lot of experience using a rotozip-type tool and you know what you're doing, because it can be dangerous if you don't. So we're just trimming the edge there, and then we're going to go ahead and trim the other edge. Then what we're going to do is rotate the plastic and we'll continue the process. It's much easier to do this if you have a jigsaw or a scroll saw, because you can just make the cut continuously, and it doesn't require near as much finishing. But we only happened to have a Dremel with us at the time, and so that's what we decided to use. And in the event that that's all you have as well, then this will be a way for you to do it. So we're using our ruler to measure 90 degrees-- to measure across to find the center, and then we're turning the circle 90 degrees to make sure that the center's in the right place. And once we've found the center, we'll be able to drill a hole in the center of the lexan and that will allow us to rotate around a specific point. And we'll be able to grind the edge of the lexan down to an exact circle. So we're drilling a hole in the center for our machine screw to fit in. And you can use a nail if you happen to have one and you don't have a machine screw. A nail will probably actually work a little bit better because you could just nail it through the lexan into the board below. But we happen to have a machine screw so we're going to use that. We're just trimming the edges off of the plastic that was sticking up. And now we're going to clamp down our board. And this is just a scrap piece of wood that we happen to have. And we've measured the distance to the center in from the edge of the board. And we're going to drill our machine screw-- or make sure our machine screw fits. And then we're going to put our plastic over it and put the machine screw in. Again, if you have a nail, you can just drive a nail through the lexan, and then pull it out after you're done. So we've got a grinding bit on our Dremel, we've clamped it in place, and it is just a little bit above the edge of the lexan. And we're turning it and rotating our lexan as we go around and around to remove the burrs and the edges to make the lexan truly round. So we're fast forwarding through this because it takes a while. The whole process took about, I think, about five or six minutes because you just want to keep turning it to take down all the high spots, so you get a nice, clean, round edge. So now that we've got that pretty well sanded down we're going to verify that it's round, and it looks like it's pretty round. And we'll take our screw out and put it in place. Yeah, that's going to work well. You can see the screws go in the edges so it's important that it's fairly round. OK, the fastening screws. OK so now we're going to use our file and just clean up the edge. There's some burrs and things. We're just going to again push the file away from us and just take the rough edge off of the plastic. Right, now that we've cleaned off the edges, we're going to mark the points, or the holes, that we need for the screws that are going to go into our polystyrene housing through our lexan to hold that lexan base in place. And so we're just going to mark those with the Sharpie there, and since the material is clear we can see right where the holes need to go. So we're going to clamp that material in place, the lexan, and we're going to use a 3/32 bit and drill our holes in the lexan. And we don't need to use a drill press or worry too much about the holes being perfectly centered or perfectly straight up and down, because the material is very thin, so if the holes are not perfect, it's OK. Now it is important that we try and get them as close to the center of those screw bosses as possible. Otherwise we won't get as good a fit. So we're going to use our break-off blade knife to trim the-- there's a little bit of excess plastic around the hole from the drilling, and we want to trim that excess plastic off so that we can get a nice tight fit with our screws. So we're just going to run the knife around the edge there, and we'll do that on both sides for all four holes. And we're just fast forwarding there so you can see it in action. Now we're going to take our screws and put them in place. And this part is really critical. The polystyrene housing is very soft and so you want to turn the screws very slowly when you put them in. Otherwise you'll strip the threads out and the screws won't hold very well. All right, so now the housing is complete and we're ready to begin creating our wheel mounts, or our motor mounts.