I think that if you are using triangular kinematics and have an accurate distanceBetweenMotors and an estimated rotationalRadius, you’ll be wll close enough to see a 1/2-inch square through the 3&5/8-inch opening in the router base. I don’t think you will have to do any manual movements. When I do the calibration from scratch, I’m off by only a cm or so.
However, if you are looking to use this as a substitute for the current calibration technique, then you would need a set of manual movements to align the sled to 0,0. From that point on, you shouldn’t really need to.
I’m thinking it might be better to try to build a “router bit” to hold the camera. The router has a 1/2-inch opening, which is well large enough to hold any endoscope camera if you can adapt it. Unfortunately, the cable comes out the back side but I think if the cable is flexible enough, you can build a 1/2-inch “bit” long enough you may be able to get the cable out the side leaving enough of the bit to go into the router. I have lots of 1/2-inch wood dowels (hopefully they are at least 1/2-inch and not undersized) and have a drill press, so I’m confident I can drill a hole dead center of the dowel (I know I can’t do it by hand). The rest isn’t critical so I’m thinking a dremel tool might work to cut the notch… glue it in place and it shouldn’t move. Most of the endoscopes you see for sale these days tout their semi-rigidness, which is actually a detractor for this idea. So, cheaper the better.
The advantage of doing this is that you don’t have to build an analog for the router (so the center of gravity is consistent) and would work with any router with a 1/2-inch opening.
This why I filled the request for a pencil holder that you could chuck up. I’m still trying to testing get to that. It makes the use of centering a non issue. I however want to set up a know off set on my sled as well to permanently mount a pen/pencil. Keep up the great work.
It might be… just will have to see how much clearance I have. Likely the router will have to be at its highest point on the z-axis. Though I suppose that you don’t really care what its accuracy is at the highest point… hmm.
I checked with mine, too long for a Ridgid22000. A stack of rings sized like the router body, with a central tube to guide the 'scope and the middle rings hollow to hold ballast might work.
Ok… back to plan A then (stack of rings). I bought some aluminum flashing this weekend to cut to make the tube. Just figured it would make for a nice round body and I don’t have to be as accurate with the wooden rings inside it. Just need the camera centered.
Part of the problem with my endoscope is that the body is not uniform. The lens end is a little wider than the rest of the body (the lens is a cap over the main housing).
Therefore, to slide it through a ring, I have to make the ring the size of the camera lens end. This might not be a problem as it gives plenty of surface to fill with glue or something to hold it in place.
Some pens are like that. To take care of that, I find a plastic tube or telescoping set in the model railroad section of the hobby shop to slip snugly over the narrow part and make the whole thing one dimension. Then choose a brass tube the next size larger as the central axial tube for it to ride in. If the sizes are right, the pen/camera assembly can slide in smoothly with no side-to-side movement and be adjustable for depth independent of the z-axis. This does require a well-stocked and understanding source of modeling materials, though .
But I can’t get the tube over the smaller side because it won’t fit over the lens cap and won’t fit over the USB plug. But since you suggested, I think I probably could wrap a piece or two of tape over it to raise the thickness…
I’ll probably try to make up the difference with some tape and then just glue everything in place. Its a real cheap endoscope and if I need one later, I’ll by a new one with better camera and semi-rigid cable. It’s annoying to use the one I have for its intended purpose, so might as well use it here. I just need to get out to the shed and get some circles cut. I also still have to source a calibration pattern. Finding pre-made set of squares on a background is turning out difficult. Polka dots, no problem, but circles won’t work because you can’t detect their rotation.
I tried a b&w version of it, but the software had a problem recognizing just the deep black. I can spend some more time trying to see if I can adjust the threshold.
I’ve been following this thread with interest. I have nothing constructive to add other than It would be very interesting to see if there are any correlations across the frames of those who try this out.
My feeling is that this will eventually provide data to improve the calibration of all Maslows - that the data gathered will be rolled into the firmware if/when we find any distinct patterns.
Early in my career I worked on a research project and the chief researcher said that even if we are poor scientists (i.e., it turns out we can’t accomplish what we think we can) the data we collect will be valuable to someone, nevertheless. I’m approaching this from that perspective. Even if we can’t reasonably utilize the data to make “on-the-fly” adjustments to the position of the router, it should be useful to someone for other purposes. And its cool.
I’ve been thinking about another way to mount a camera. I saw some endoscope/borescopes with “45 degree” mirror attachments. I wasn’t sure how well they are built (some are just film over plastic that wear off when you try to clean them). How 45 is their 45? So I thought about the idea of building something like it, but could fit into a 1/2-inch router opening. The basic idea is to use a half round of some type of metal (stainless steel for example) that’s been polished to a reasonable mirror surface to reflect the image to a horizontally installed endoscope (it just has to be “good enough”). This allows the endoscope camera to be really close to the bottom of the router head and the cable can pass out through the vacuum port. This is a diagram of what I’m thinking about.
If I use a 1/4-inch half round stainless steel and polish the flat side to a mirror finish, I can cut off about 1-inch of it, put some epoxy on the backside and slide it into the dowel. With the camera in place, I can rotate the mirror to align the angle to 45 degrees (size the half-round to be ~1-inch long so it extends beyond the dowel to allow adjustment). This should give me a view of straight down in-line with the a router bit. Ideally, the camera would be a smaller diameter or the half-round be a larger diameter, but this is what I have on hand.
I think I can drill the holes for the dowel fairly accurately with a jig and a drill press. The idea would be to take a wooden block (could even be one of my million chunks of 2x4) and drill a 1/2-inch hole through the long side (end grain). Flip the block on a side and drill 1/4-inch hole all the way through. Flip it over on the other side and drill a 7.5 mm hole through. Insert dowel and using the previously drilled holes as guides, drill the 1/4-inch and 7.5 mm holes into the dowel. The critical part will be drilling the holes in the right locations initially.
I would think that the hardest part would be in getting the piece of half round to be flat and shiny. I wonder if you would not be better off cutting a small piece of mirror and attach it to the 45-degree cut. I would think that it would be easier and glass is not that hard to cut.
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