Electronic Targets - DIY?

[Stot]

Thanks very much for your input Stot

The web cam will need to be out of pellet's harms way...

The camera would be outside the box pointing at it from the shooters POV. Doesnt mater where exactly as long as it can focus on the target, few meters away.

I would have thought that repeated pellets smashing into a translucent back stop will eventually mark and degrade its optical properties. Might require constant cleaning. Something I want to avoid.

Me too.

However, I'm not looking to electronic score a paper target (others might though). In my vision, I want to remove the paper target completely but also electronically score.

Oh I see, but what would you aim at?

If you still want to use paper targets and video camera there are these systems:

http://williamson-labs.com/target.htm

Pretty much this idea but a little less.... complicated.

I have a camera that will shoot video at 1000fps and this wont capture a 12ftlb pellet in the air at 20 yards.

Cheers
Stot

[Synthasy2000]

....but what would you aim at?

It would be the centre of a black hole.

http://www.edinkillie.co.uk/ecatalog...link/4k187.jpg

Pretty much this idea but a little less.... complicated.

Yes it did look a little long winded!

I have a camera that will shoot video at 1000fps and this wont capture a 12ftlb pellet in the air at 20 yards.

In 1ms the pellet would have travelled 25cm so I'm not surprised.

But there's a weath of slo mo pellet vids on YouTube

http://www.youtube.com/watch?v=b73pFcVdmRE

[Stot]

Just had a thought about this.

How about having a steel plate, spring loaded toward the shooter some. Behind the steel plate are 4 pot resistors 2 on X and 2 on Y.

The plate needs to be mounted in such a way as it will move slightly when hit then return to its initial setting. Maybe on an old mainspring dead center of the plate.

As you shoot the plate in different areas, the plate would move and adjust each of the 4 pots differently. Use some electronics to keep track of the max setting each pot gets to then by knowing where the pots were, you could in theory work out where the pellet was.

You could possibly even strip a joystick or wireless PC gamepad controller and use the X-Y and Z-Thrust axis to do your measuring and use the PC to score. Gamepade have +-128 positions per axis normally.

Cheers
Stot

[Synthasy2000]

Wow Stot - your noggin' is certainly a thunkin'

I love your diagrams. They make everything very clear.

Conceptually it seems fine although I think the devil is in the detail.

The target plate will need to bit thickish steel as per normal pellet trap. Then a spring is mounted behind it and then the target is hung vertically. I think they'll be some vertical slop here. So the target plate will need some supports at the corners.

Also, springs boing so some form of damping will be required. Perhaps a piston in a cylinder and a spring arrangement.

Technically only two position sensors would be required (X and Y) but 4 would help with getting a reliable result. The sensors at opposite ends should be antagonistic i.e if one shows a 10, the other should show -10. There will always be some rearward motion of the target regardless of where it is hit so perhaps this becomes 15 and -5. There would be a "DC" components to the values which could be ignored although to some extent this value represents the "power" of the pellet.

I don't think you can use pots or slider pots to sense the position. There's too much drag and they won't be reliable after many shots due to contact wear. You could use a rack and pinion arrangement connected to an encoder like those used in ball mice on PCs though. But can they be scanned fast enough? How long does the target plate get deflected for?

Also, is there enough resolution? A shot in the corner will deflect the plate the most and a bullseye the least. How much deflection? 20mm?

It's a great suggestion and it may work but I think there's too many mechanical elements here for me. My stengths are electronic not mechanical. If someone's skills are more mechanical than electronic, this could be the way to go?

[Cones]

http://www.positek.com/

Non contact position sensor

As used on F1 cars. and rock crushing machines

HTH

Mark

[Synthasy2000]

Non contact position sensor

You can always solve a problem by throwing money at it

But to do it cheaply? That's why I said use encoders from a mouse.

[Stot]

I think the mouse wheels could work too. Mounting could be via some RC suspension struts giving the spring and damping properties.

Fairly easy from a software point of view too with a mouse driver. Calibrate the mouse to the center of an on screen target and as the table tilts, the mouse pointer moves toward the shot. Software does some recording of max movement and works out the shot position.

It would need to be calibrated for power as a .177 12ftlbf shot would move the plate less than a .22 12ftlbf shot. So you set the pointer middle onscreen target. Shoot at the corners of the target and tell the program where on the on screen target you hit. Calibration done. It now knows how far the mouse moves for a given shot with your gun.

Cheers
Stot

[Cones]

You can always solve a problem by throwing money at it

But to do it cheaply? That's why I said use encoders from a mouse.

True. But I have seen the contact version affected by vibration.

Perhaps you could use a comb type arrangement with the mouse encoders. Then you would not have to convert linear to rotary motion? Just needs someone to machine some fine slots into some flat bar.

Mark

[Stot]

True. But I have seen the contact version affected by vibration.

Perhaps you could use a comb type arrangement with the mouse encoders. Then you would not have to convert linear to rotary motion? Just needs someone to machine some fine slots into some flat bar.

Mark

Or some laser printed acetate.

Or a 'laser trip wire' array. 11x11 with 4.5mm resolution. direct X-Y positon detection for a 0-10 scoring.

Cheers
Stot

[Synthasy2000]

Stot and Cones => great suggestions.

However, I think this would work only for relatively slow movements. A mouse encoder gives a few hundred readings per second. Although we are only looking for maximum deviation here and not to record the entire journey. Also, using the laser printed lines method we can decide our own pulse rate to the encoder.

How long does it take the plate to go from rest to maximum deviation with a pellet strike? 5ms? 500ms?

It's still possible though and is fairly elegant and cheap.

Personally I'm investigating an optical sensing method. But I'm not abandoning this idea.

Chris

[Synthasy2000]

The optical scheme I'm devised allows me two options.

1) A full 17cm by 17cm target sensing area but a 1.25mm resolution
or
2) A 6cm by 6cm target sensing area (nominally the black area of the target) but a 0.5mm resolution.

I'm favouring option 2) as in this emulates the professional electronic targets and gives the highest resolution but I can see option 1 being useful too.

Note that it will be very dificult to switch between the two. They would have to be different products.

Chris

[Garry]

I'd go for the 2nd option. If you're not hitting the black every time anyway you probably wouldn't even make it into a club team, never mind the olympics.

[eggplant]

Hi all,

Only just joined and thought I'd have another read before I posted a welcome, then I came accross this thread.
Just quickly read over as its a bit late but will read properly tomorrow (today..)
It is of interest to me because I am just in the process of making something similar but at the moment I've only got a protptype of it going left right, up and down - works fine but is only about 20inch long (outer box from one of these knock down/reset targets with the 4 metal rabbit shaped targets). Works ok so am in the process of making a longer (about a metre) one.
Ideas are pop standard paper type targets at random positions for set/random times, pop up metal falling (which of course aotomatically reset) at random/set times, and 2 types of metal falling target, a "goody" and a "baddy", the baddy would loose a point.
Only place I have to use this is my garden which gives me a shooting distance of about 10 metres.
I have if sussed to monitor the knock down targets and score pretty easy, am looking into ideas (cheap!!!) of getting an accurate way of detecting a hit, had a few ideas but none likely to work for more than one shot ! Some of the ideas mentioned here in my quick skim through sound good and may give me more ideas.
The original reason I ended up with an air rifle (S410 carbine) is because I wanted to do some high speed photos with another project I am on with to control the camera on given events such as sound, beam breaking etc (couple of links to test shots below if anyone is interested)so I blindly bought a .177 pistol (Beeman 2004), whilst the people in the shop were very helpful indeed, one thing that wasnt mentioned was velocity - I may yet buy a cheap .22 pistol for this purpose. I recently met up with a good friend who I hadnt seen in ages who has a very large garden and had 2 air rifles but has just got his FAC so was going to trade them - apart from my photos, I obviously had the odd plink with the pistol in the garden and quite enjoyed it, so helped out my mate by buying one of his !
Anyway, enough waffle, I'll read this post properly later and hopefully be able to throw in an idea or two about the original topic.

Couple of the photos I took to test the camera project of mine which started off as a sound trigger (£<10) to take a pic of a dart popping a balloon, it has now snowballed to the cost of a used S410 with bottle, decent scope, digital camera sensors etc, and now a moving target system and maybe a new pistol !! (as you do ....)

strawberry being shot

couple of test shots on a balloon

few test shots on fruit - the coke glass isnt being shot - its an ice cube being dropped in it testing another sensor !

[Synthasy2000]

There are some great pictures there. Keep up the good work

Have you seen this thread too on automated targets?

http://www.airgunbbs.com/forums/showthread.php?t=455968

[Cones]

There are some great pictures there. Keep up the good work

Have you seen this thread too on automated targets?

http://www.airgunbbs.com/forums/showthread.php?t=455968

I might have.

Thanks for the link.

Mark