# Visual Hollowing



## kweinert (Jan 15, 2015)

I saw a post over on Lumberjocks by TheDane (http://lumberjocks.com/TheDane/blog/45489) which has inspired me to finally take a look at this process.

I didn't like the camera he purchased as the reviews overall were pretty negative. 
So, I ordered and received a different camera (http://amazon.com/gp/product/B000YM2OIK) and it came in yesterday. I was able to test it out yesterday and it produces acceptable pictures. I’m sure once I’ve gotten it in place on the hollowing system I can fine tune the picture a bit more. You can adjust the focus and the tuning on the receiver. I adjusted focus by moving the camera for my test :)

Then, in search of a TV for it I just purchased these from Amazon as well: a headrest monitor (http://amazon.com/gp/product/B007SLDF7O). I was looking for inexpensive and I don't have a spare TV with analog inputs around to give it a try. Since it's meant to go in a vehicle it needs a 12v supply. I picked this one because it will do the job and it has a plug on the end that I can use for the TV. (http://amazon.com/gp/product/B006NTNGN0). Those should be in on Friday.

I’m hoping the 7” TV is sufficient for hollowing. If not I’ll buy a backup camera and use this in the vehicle for what it’s designed to do :)

In the end, for about $50 I have all the pieces I need to try out the visual hollowing system and see if it works. I’ve certainly spent more for experiments that haven’t worked out and all the pieces are usable for other things so I really won’t be out anything if it’s not to my liking.

I've seen a system like this demonstrated at our local turning club last year. It's pretty amazing to watch. I think it's easier to use than a laser system. I've used a laser before, only seen the visual demonstrated so I could be wrong. It is pretty slick to watch though.

I'll certainly post pictures when I get it all together - and I'll try to make a video (my first) if I can find the camera to do so.

Reactions: Way Cool 1


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## TimR (Jan 15, 2015)

Ken, this appears to be based on a system I saw Trent Bosch demonstrate a couple years ago and that he sells, called the Visualizer. It's a neat approach to better understand what the cutting tip orientation is vs a laser. I used an old laptop I have and just bought a $15 USB endoscope from ebay and stuck it in my hollowing rig next to where the laser would normally be. I used dry erase markers on my laptop screen, and it works fine. Do I still use it when hollowing? No, but that's because I've gotten so used to using my laser or nothing, and I'm an old dog.  The key to putting together a well designed system is getting the focal length for the camera better matched. The cheap one I bought is best at a couple inches or less, but it's just ok at the 10-12 inches away I have it mounted. I may experiment with it some more, but haven't been doing much laser hollowing lately.

Reactions: Like 1


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## kweinert (Jan 15, 2015)

Trent is from here in Colorado and he's the one that demonstrated here in Denver as well.

And I'm not exactly a young pup myself - on the other hand, when it comes to hollowing I could fit that description. I could see that if you're used to a system a different system might not make sufficient difference that one would make a change.

After all, in spite of all the new languages out there I still prefer to program in C/C++ :)


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## gman2431 (Jan 15, 2015)

I know nothing about it but would love to see what you come up with !

Reactions: Agree 1


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## kweinert (Jan 22, 2015)

So, the TV and adapter made it in and at first I thought I was in trouble. When I pulled the TV out of the box it had a plug on it. Not the bare wires I thought I'd see. Then when you look for the directions and pull up the flap at the bottom of the box you find the other side of the connection and it has the bare wires on it :)

Sigh of relief.

I hooked the camera back up and plugged everything in and it looks great. The picture from that small camera is much better on the smaller screen than it was the 35" TV. In retrospect that makes sense since we aren't upsizing to an HD size TV. Much easier to throw pixels away than create them. In short, I have a really clear picture on the headrest TV.

The TV itself has a bezel that it fits in to so there are several ways that it can be mounted. Since I only plan on using it on the one lathe which is up against the wall, I plan on throwing together a frame that will attach to the wall and hang over the headstock. I'll mount the camera receiver on the same frame and also attach a short power strip to the side of the frame against the wall so the power supplies for the TV and receiver can plug in there and I'll only have to have one side of an outlet to get all that working.

Once things get warmed up I'll get that built and post up some pictures of my setup.

Reactions: Like 1


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## kweinert (Jan 25, 2015)

Just a progress report. I don't yet have the camera mounted to the tool, but I do have the mechanism set up for the TV and receiver. Well, mostly.

I cut some 3/4" pine at 1 1/2" wide. I should have made it just a tad wider for how I ended up using it. Here's the basic layout for the frame.





I decided to use the frame that the TV came in to fasten it down. That open area to the right of the frame is where the wireless TV receiver will fasten down. You can see that I added a couple of cross pieces behind and screwed the frame down. When I first had this in my head I thought I was just going to run screws through the side of it into the frame. Then I asked myself why I want to drill more holes when there were perfectly good ones already there.





The back side. You can see that the braces stick out just a bit. I probably could have used some 1/2" ply instead. The notches are there because the TV frame has protrusions there. And if I were planning this better I would have fastened in the braces before I put in the other piece for the receiver. Hard to get a nail gun in there :) All the wood is glued and nailed.





Here it is in place - sort of. I'll be putting drywall anchors into the wall and all that nice wiring will be tucked and zip tied up out of the way. I will be mounting a power strip on the top of the frame to plug everything in to. Turns out the cord of the one I had on hand is a bit too short to reach the outlet.





Here's a picture from the camera.

I had an interesting time getting this in tune. When I first tested this after it came I had everything plugged into the same powerstrip and this is the sort of image I was getting. Out in the shop I had the camera plugged into a different outlet and I just couldn't get a good image tuned in. It was bad enough that it wasn't really usable, even. It took me a while but I eventually remembered that my initial test had everything the same. When I plugged the camera back into the power strip the picture cleared right up.

A couple of things: the camera does have a 9 volt battery option and as soon as I have a charged 9 volt battery I'll give that a try. I would be easier in the long run if my tool wasn't anchored to the wall anyway. The other thing is that the outlet closest to the camera is a GFI circuit and I wonder if that's related to the interference I saw.

So, to finish up I need to:

get new powerstrip and mount it
mount frame to wall
test 9 volt battery
attach camera to hollowing tool
put a small frame to hold plexiglass in front of the TV so I can draw on it

Then I'll be ready to go. And I'll try filming my attempts to use it. Since I've not done filming we'll have to see how that goes :)

Reactions: Like 4


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## MikeMD (Jan 27, 2015)

Neat little setup you've got going there. I'll be watching to see how this progresses.


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## kweinert (Feb 23, 2015)

OK, just a quick update, pictures later (since I'm at work and can't run out to the shop to take them :)

I picked up a power strip to plug the monitor and receiver into. That's now zip tied to the top cross piece next to the wall. All the excess cordage is zip tied to the bottom cross piece.

I turned a piece of 3/4" wood to fit the hollowing rig where the laser would normally go, leaving one end square. That end I CA'd to the back of the camera. I had some 3/16" plexiglas sitting around from making templates, so I cut a couple of pieces of 3/4" pine to fit on the end and bottom of the mount. They extend out towards the front of the mount and are grooved so I can slide the plexigas in. That's what I'll use my markers on to show the tip and such. That way if I forget and grab a sharpie I can replace the plexigas and don't have to worry about the screen. I guess it could afford a bit of protection to the screen as well in case something comes off the lathe.

I have tried the camera with a batter and that works just fine. I don't know how long it will last, but I think I like that better than having it plugged in to the wall. The fewer dangly things around spinning wood the better.

Sorry it's been so long since I've updated. I've done a little here, a little there, but between the cold weather and the need to finish a rocking tractor before a certain young lady's birthday I've not had a lot of time to spend on this project.

Reactions: Like 2


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## justallan (Feb 23, 2015)

Very interesting posts, Ken. I'll be watching for the end result.
Does this work like a snake camera, or am I just way off track?


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## kweinert (Feb 23, 2015)

No, not like a snake camera. It's really interesting. Here's a video that Trent put up on YouTube to show how it works.


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## MikeMD (Feb 23, 2015)

Ok, so how the heck does the image of the tool stay on the screen?


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## DKMD (Feb 24, 2015)

MikeMD said:


> Ok, so how the heck does the image of the tool stay on the screen?



It's drawn on the screen. Since the cutter position never changes relative to the camera view, you can 'see' the cutter while hollowing. It's pretty nift, huh?


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## MikeMD (Feb 24, 2015)

It did kinda look like it was drawn on there. Though maybe it used X-ray vision! 

If the camera is mounted directly above the cutter on that arm, like our lasers are on the Monster rig, what if the camera moves from vibration or accidentally whacking it? Also, what about when you change cutter heads? Do you have to keep redrawing on your screen? Is it a special screen to be drawn on? So many questions!


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## DKMD (Feb 24, 2015)

MikeMD said:


> It did kinda look like it was drawn on there. Though maybe it used X-ray vision!
> 
> If the camera is mounted directly above the cutter on that arm, like our lasers are on the Monster rig, what if the camera moves from vibration or accidentally whacking it? Also, what about when you change cutter heads? Do you have to keep redrawing on your screen? Is it a special screen to be drawn on? So many questions!



It needs to be secure... More so than the Monster laser.

You do need to redraw the cutter if you change tips or tip position. I don't think the screen is special, but you also don't want to use a Sharpie to draw the cutter on it.


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## kweinert (Feb 24, 2015)

I just put a piece of Plexiglas in grooves in front of the screen and will use dry erase markers to outline the cutter.

That way I can replace it if someone accidentally uses a sharpie instead. Not that I would ever do that of course :)

The advise I've been given is to put a ruler next to the cutter when you draw the wall thickness around the cutter as it may not be (probably is not) a one-to-one scale from the camera.


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