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A microcontroller based moving target stand - update, but still orginal video

3K views 22 replies 12 participants last post by  Tangle 
#1 ·
This is still a work in progress. I debated not posting anything until it was in final form, but I think a lot of members might enjoy seeing the progress so I opted to post this at a very early proof of concept stage and post updates as they come. Plus that will be added incentive for me to not drag my feet on the project.

Currently, I'm just testing with manual go/no-go switches. But it will culminate in a very portable moving target stand with microcontroller control of motion. The microcontroller is the easy stuff for me, the stand itself has been a bit more challenging.

My goals were to design and construct a very compact, lightweight, maximized range of motion with programmable, manual, and random start/stops, etc.

I've been working on this for a while now. What you're seeing in the video is actually a 3rd generation and since I made the video (day before yesterday) I've already implemented some changes (cabling) and re-designed the target holder carrier - the orginal design chatters and it would just get worse.

Unfortunately, the YOUTUBE video is pretty bad sound wise. The wind was blowing enough to be significant and of all things a train or two went by - a loooong way from my house, and there's an interstate nearby so there are sounds from it too.

From this test, I'm thinking I need a faster maximum speed, but the way I designe the drive, that's a matter of removing a single 17 tooth sprocket and installing a larger one. I'll probably try several different sizes.

YouTube - MOV00090

Keep you posted,
Tangle
 
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#3 ·
It looks like it uses string to move back and forth. You may be better off using a power window motor found inside a car door. They have several diffrent types and wil require a trip down to the junk yard. Some have a ribbon stlye that could be adapted to move the rig back and forth. Would get better life out of the ribbon than the string. So have an arm that can be removed and geared up or down to regulate the speed. The motor will last forever and with the install of some automatic resetting circuit breakers to stop the rig so you can limit of travel. Looks like a good set up.
 
#6 ·
I am using a window motor. I think it's probably marginal but I'm anticipating acceptable life from it. I have a windshield motor that I believe would be better power wise, but the shaft would be really tricky to mount a sprocket on.

The nylon string 'cabling' was just for a quick test to confirm motion and range. The nylon cabling has already been replaced with .065 weed eater line - that's looking much better. The cable drive is rather complex, providing motion multiplication and proportional positioning of each frame of motion to the next.

The final product will use 'soft' limit switches more for determining range of motion than limit per se, each time the unit is powered up. I'll implement a discrete quadrature phase detector incorporating the primary drive chain to determine position. That's about the easiest, most robust way I've come up with so far.
 
#9 ·
That is a good question!!!!

Maybe a $200 deposit?

Qualification shoot?

Very close monitoring of anyone using it?

Don't let anyone use it but me?

Seriously, there will be no bullet proofing. I don't mind the uprights that hold the target getting holes in them - I'll probably put some holes in them myself. I'll just have to be real careful who I let shoot at it.
 
#11 ·
I know exactly what you mean about that errant round! That would put a real damper on things.

That's not a bad idea - a plate that would protect the "...delicate bits..." - I guess that's analogous to a guy wearing a cup - for the same reason.

A piece of steel thick enough to handle a bullet would be pretty heavy, but it could be handled separately and that would help.

Unlike the implication in the video, the base will be at ground level rather than waist high as shown in the video and that should help some too.

Still your concern is well justified even with the delicate parts at near ground level. This is intented to be a threat initiated 'go' signal rather than a 'go' or 'gun' or whistle command. Hence someone trying a little too hard could easily let one go just a little prematurely on a draw and fire and that could do it.
 
#12 ·
I think the separate steel plate would be the way to go, to make it more portable. At ground level, you'd have to worry about what angle the plate is sitting at in relation to the ground, as a shooter that's very close could find it easier to accidentally shoot over the plate into the workings. I don't think lead splatter would be a worry.

The plate may need to be staked into the ground somehow, so it doesn't creep back into the target stand.

-JT
 
#14 ·
Since we 'talked' last :tongue: I remembered that my club limits the shooting of steel to 25 yards - I believe that's the rule, so steel would be pretty much out at close range - but a short railroad tie, now that might have some promise.

Maybe a short RR tie with detachable wheels (so the wheels don't get shot.
 
#15 ·
I think laying out the system "right" would minimize the size of a protective shield. The motor and electronics could be kept in one side close to each other behind a small steel shield. The largest sensitive parts are probably the rails. Maybe make them easy to swap ? If you can't protect them, make them easy / cheap to replace. And the further you can increase the distance from target to the mechanism, the better. E.g. keep the mechanism on the ground and a long "stick" to hold the target up. I will be a bit less stable so you have to check what works.

If you use a metal plate: Look at some of the commercial targets. They usually angle them a bit to minimize splatter back at the shooter. I would probably use wood to hold the target.
 
#16 ·
Great looking rig, wish i could build something like this. I can come up with some good ideas but am never able to build them for some reason or another.

just a suggestion here, I know that you said that you were going to have this at ground level, but what about having a small framed wall with a window in it and the rig could sit where the window sill would be. this way the target could apear from either side of the wall or in the window it's self. The steel plate could be built into the wall to protect the track and working parts.

Again this is only a suggestion, as I do not know if you will be using this at a public or private range, or as to your local ect.
 
#17 ·
Some great ideas guys!

I contacted the president of my range and confirmed that 'steel' is not allowed closer than 25 yards. He did say he had no problems with the target itself.

One suggestion was sand bags; that would be good, though could be messy, but that'd still be better than getting bad damage done to the target.

I'm sure glad I posted this a bit early - you guys are giving me a lot to think about.

I'm not too worried about me shooting it. I regularly shoot with a steel tube target stand (static) and have never shot anywhere near low enough to hit it. Although, now that I've said that I'll probably put the first round through the gearbox.

But if I had somebody else with me, or somebody at the range wanted to give'er a try...
 
#18 ·
I've redesigned the target carrier that was causing the chatter and in theory, I'll install the new carrier tonight, now that 24 and NCIS are over for the week.

I'm also gonna replace the inner frame with a lighter gauge tubing to cut down on the mass that has to be accelerated and decelerated. One of the larger sprockets I ordered is in so I'll install that too. That may take the entire night: I have to machine the bore to 0.354" (9mm), drill and tap two set screws at 90°, and I may decide to broach a keyway in the sprocket for added security which means a slot has to be milled into output shaft also. Uuugh! That's a lot of trouble, but I think it'll be worth it. Set screws alone, especially at this torque level can slip - keys don't.

I may have more work than I anticipate, it usually is, but I hope to have a new video by Friday or Saturday. I think I have an existing controller set up for controlling it, but I'll have to add switch and sensor inputs - shoot - that's more trouble too. I'll wind up redesigning the entire board. Oh well, I must remember to be patient, it'll be worth the effort in the end.
 
#20 ·
I'll take the first production piece you put out. Never mind the cost and shipping, make it go real fast back and forth, 6-8 feet from side to side and let me know what you need in advance to start the project for materials and labor.

I'll be the only one using mine.

Does that give you an idea I like it Tangle?:35:

Brownie
 
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