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AndyGif290368

Expected impact joule'age at a distance

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Hi, anyone good at maths/physics/ballistics around here.

I'm trying to build an electronic hit register, a fancy term for a metal target that goes ding and lights a light when it's hit.

To aid in calibrating it, what is the likely joule'age going to be say, if we take a nominal gun firing a 0.2g bb at 330 FPS at the muzzle, at 30m downrange.

I don't have 30m of garden to do this in, so if I know the expected joules, I can't drop a heavier weight on it from a shorter distance to register the same impact. ie 100g weight dropped on it from 1m, this too is also nominally 1j....

 

ok, which would you rather get hit by???

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it's actually quite complicated... a .20g BB will have less energy after 30m than a .30g will even if they're both fired with exactly the same muzzle energy.

 

someone did a LOT of maths on this a while back over at the airsoft trajectory project:

 

http://mackila.com/airsoft/atp/07-b-06.htm

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Plastic milk bottle

Tin Can - aerosol can

Flower pot (small if possible)

 

Shove stuff like that down end of garden

even if don't see the bb hitting those few targets

you will know by sound which one is getting shot

dial hop, zero sights getting shooting as best as possible

 

When you have sussed it - then try and see how good you are shooting with left hand/peeking left (or vice versa if left handed)

 

then try to hit a sneaky bastid moving target that shoots back at ya and doesn't always call their hits = totally different target to shoot at

(stand still ya sod and if possible just pop ya head up a tiny bit more please)

 

peew peew

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Sittingduck is it your mission to have a post in every thread??

You've added nothing to this thread.

Why would I want to destroy cans, bottles & flowerpots when I can with some electronic parts to make something reusable. Oh and my garden is about 20ft long, I could almost poke the targets with the muzzle at that distance.

 

The answer from the link provided, would seem to indicate about 0.2j at 70ft mark

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Sometimes I wonder the same about SittingDuck. Besides, once you have an electronic system like that set up, you can set it to do all kinds of things, develop it etc. For example, once one target or x number of targets has been hit, release another target, or release a moving target, etc etc.

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Fair enough you generally give good advice, and advice that some others can't provide, and clearly you're very experienced, and you're rather helpful. You come across rather harsh though, and sometimes I feel like you just write anything you know as a post that vaguely relates to what they ask, for example: Targets - you write anything you know about targets. I just wish you'd focus your experience and knowledge into something more specific. i.e he specifically asked about electronic targets, logic dictates that cans etc aren't what he's asking about.

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Uhm - yes I know I go way way way way overboard numerous times.......

 

As Trigger said I was merely pointing out a rather more simpler method for knocking up a set of targets

Also pointing out that a good target system or marksman doesn't itself equate to dominance on the field either

The OP never stated the exact distance - just said he didn't have 30m back garden

 

Depending on the project in mind the OP could use stuff like tactile switches protected by say an aluminium top plate

Building a target similar to G&G's MET overpriced target system like they use in their competitions or something

Or adapt an existing crappy £10-£20 off the shelf target and develop it further if wanting a smaller scale thing....

 

Either design & build something from scratch or develop something further - improving on a previous design/model

My post was to point out in a lighthearted way that often the plain & simple stuff works quite well

Fine - add an indication if you wish, probably using low tactile switches as I said....

Sort of low pressure ones switches like used in keyboard perhaps protected with a sheet of stuff

This top target/sheet could be easily changed for different sizes/shapes even

eg: start off with an easy 4 inch round target, then drop down to a 1 inch round/star/any shape covering for real fine marksmanship

Reason I give the "keyboard" type switch is you would want some "travel" to push the switch or rebound/ricochet could trigger surrounding switches.

Light to moderate pressure with a bit of push travel but not as high as some latching emergency stop buttons used in industry

 

The only thing I took umbrage to was that OP & his friend started on me so quickly stating I added nothing to this thread etc.....

There are numerous Advice quotes like Advice is given freely coz so much of it is worthless etc.....

(No doubt that line probably applies to me a lot)

 

However - often it is very wise to consider/listen to all advice however foolish some of may sound at first

Ignoring advice is one thing, scoffing advice is another, 2 people so soon to have a pop at moi is another

 

I was not mocking the concept - merely pointing out an easy simple option trying to help

plus pointing out there is more to this stuff that just shooting targets - still/moving/electronic

 

No worries - wish you well anyway like I said

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I respect what SD does on the forum.

I wish I knew what that actually is because most of the time it's TL;DR for me and I only read a few of his lines. :D;)

 

On topic: there is a guy in Hungary where I'm from who built an interconnectable, sophisticated target system for airsoft. I don't know if he speaks English or not but I can try to get his email for you. The target is a metal sheet with sensors and works good even on long distances.

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FFS, flame war engaged.

I may be new to this forum, but I'm not new to airsofting, I started in the early 2000s but have had to sit out for approx 9 years whilst raising a family. I am well aware of commercial target systems, but was I asking about those no! As one of my other hobbies is electronics I'd rather build my own it's a challenge.

 

There's quite a few "homebrew" target systems out there, most seem to be setup for proper bullets, hence why I was asking for an expected impact value. A real bullet v a bb at 100 foot is magnitudes of difference.

 

Oh hello Imtriggerhappy, wondered where you'd got too.

 

If you can't add anything constructive, sometimes it's better not to add anything at all. There are far too many people spouting off just for the sake of raising pistage, but that just adds to the churn and you can never find the gems of truth for the pile of irrelevant dross.

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Hi Samauri, I think I've seen that one.

What I'm planning is 2 plate system, inner bull and an outer ring.

Mechanical switches are not going to be sensitive enough to register a hit at distance. It's going to be relying on piezo strips to register the hit and microprocessor to tell me which was hit.

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Hold up a sec....

 

1) - I don't need Trigger or any others on here to fight my battles

 

2) - Both yourself & I are probably about the same handwriting I think

Therefore I feel that as we may have attained a little more understanding of how the world works etc....

We don't need to instantly jump to conclusions or dismiss other people's opinions quite so easily or quickly

 

Many on here may not fully agree with others but think the wiser thing is to accept others difference of opinions

Rather than dismiss them so quickly perhaps - that doesn't exactly sit well with people trying to reply

 

I'll admit on numerous forums & message boards people have chimed in and I have thought they are talking out their ar$e

But instead of getting into a row or risk offending them I will accept their input even if I feel that it is of little or no use to me

If I feel it is giving incorrect or wrong advice I will announce that but try to refrain from me calling them a [email protected] even if I feel they are

 

The advice I gave to your question may not have been suitable for your particular instance

But others may have found it informative as they browse others threads

Plus numerous projects/ideas in our heads all sound good at the time but sometimes our ideas can sometimes become more involved than we first think

In rare cases we can find ourselves in effect trying to reinvent the wheel so to speak

Not saying your concept is reinventing the wheel but pointing out at first glance you was seeking:

 

"target that goes ding and lights a light when it's hit"

 

The different ding's from different targets is a very very basic crude method I'll admit but all the same I was just offering a basic simple down to earth option

 

No worries - I wish you well in your project and hope you can enlighten us with it when finished

I'm the first to poke fun at myself but like to think I'm able to take on board other people's suggestions

even if I feel they might not be exactly what I'm seeking - but I refrain from dismissing them so quickly

 

I'm done I think, best wishes still

 

peace to all members - new or old - we are all still learning

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Hi, anyone good at maths/physics/ballistics around here.

I'm trying to build an electronic hit register, a fancy term for a metal target that goes ding and lights a light when it's hit.

To aid in calibrating it, what is the likely joule'age going to be say, if we take a nominal gun firing a 0.2g bb at 330 FPS at the muzzle, at 30m downrange.

I don't have 30m of garden to do this in, so if I know the expected joules, I can't drop a heavier weight on it from a shorter distance to register the same impact. ie 100g weight dropped on it from 1m, this too is also nominally 1j....

 

ok, which would you rather get hit by???

To answer your question

 

A train, that would be a quick death and cause chaos for commuters, getting hit by anything else just seems pointless.

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To answer your question

 

A train, that would be a quick death and cause chaos for commuters, getting hit by anything else just seems pointless.

Depends on how fast the train is going... 5mph shunter v 150mph express.

A slow squish v a quick splat

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FFS, flame war engaged.

I may be new to this forum, but I'm not new to airsofting, I started in the early 2000s but have had to sit out for approx 9 years whilst raising a family. I am well aware of commercial target systems, but was I asking about those no! As one of my other hobbies is electronics I'd rather build my own it's a challenge.

 

There's quite a few "homebrew" target systems out there, most seem to be setup for proper bullets, hence why I was asking for an expected impact value. A real bullet v a bb at 100 foot is magnitudes of difference.

 

Oh hello Imtriggerhappy, wondered where you'd got too.

 

If you can't add anything constructive, sometimes it's better not to add anything at all. There are far too many people spouting off just for the sake of raising pistage, but that just adds to the churn and you can never find the gems of truth for the pile of irrelevant dross.

Love the way you give someone attitude then try to come across as the victim.

Any war of words is on you and your mate. SD was just giving his take on it, it might not be what you wanted but you didn't need to be an arse about it.

 

SD is right he doesn't need me to fight his battles but I will say my piece anyway.

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Depends on how fast the train is going... 5mph shunter v 150mph express.

A slow squish v a quick splat

It would still only take about 2-3seconds to die from the slow speed train. I would personally pick a London subway train just to piss everyone off.

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Hi Samauri, I think I've seen that one.

What I'm planning is 2 plate system, inner bull and an outer ring.

Mechanical switches are not going to be sensitive enough to register a hit at distance. It's going to be relying on piezo strips to register the hit and microprocessor to tell me which was hit.

I found this guy's thread on a Hun electronics forum. He uses vibration sensors. He too quickly dropped the mechanical sensors and tried with piezos but then settled for vibration sensors on a metal target plate. He uses a dismantled USB keyboard to turn the signals into keypresses that he processes with a laptop.

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Hi, anyone good at maths/physics/ballistics around here.

I'm trying to build an electronic hit register, a fancy term for a metal target that goes ding and lights a light when it's hit.

To aid in calibrating it, what is the likely joule'age going to be say, if we take a nominal gun firing a 0.2g bb at 330 FPS at the muzzle, at 30m downrange.

I don't have 30m of garden to do this in, so if I know the expected joules, I can't drop a heavier weight on it from a shorter distance to register the same impact. ie 100g weight dropped on it from 1m, this too is also nominally 1j....

 

ok, which would you rather get hit by???

 

I've been wanting to try something like this myself! Right... It's not really what you're asking but what about getting some ballistic gel and placing it at say 20 meters. You could gauge penetration depth between different weight BB's to form a chart maybe? Not sure if this has ever been done or if it would work?

 

The other option is to try a paintball chrono at a fixed distance, you could chart the drop off.

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I've been wanting to try something like this myself! Right... It's not really what you're asking but what about getting some ballistic gel and placing it at say 20 meters. You could gauge penetration depth between different weight BB's to form a chart maybe? Not sure if this has ever been done or if it would work?

 

The other option is to try a paintball chrono at a fixed distance, you could chart the drop off.

I know the type of chrono you mean. Very use full for a lot of "Range" sports, notably archery, but not very cheap.

http://www.merlinarchery.co.uk/everything-else/tuning-maintenance/chronographs.html

I do have a normal airsoft/airgun chrono, if I was a good shot I could aim for the hole I guess.

My garden's only about 20 foot long, so rather negates a lot of the external tuning. I was thinking of donating the thing to my local cqb skirmish site when I've built it.

if you can get above the level of the wooden walls the shooting space is about 300 foot long by 100 foot wide.

The mrs doesn't really like the idea of me and the boy in the garden with assault rifles plinking at cans anyway.

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Love the way you give someone attitude then try to come across as the victim.

Any war of words is on you and your mate. SD was just giving his take on it, it might not be what you wanted but you didn't need to be an arse about it.

 

SD is right he doesn't need me to fight his battles but I will say my piece anyway.

Trigger that was not attitude, i was just expressing my annoyance with SD, as he usually posts very helpful stuff in most of the threads i've seen him in.

And Destructification is no mate of mine.... he worse than that he's my arsey teenage stepson.... who will no doubt create yet another account on here now i've pointed that out .

 

Feel free to let me know if ever you get along to Strikeforce CQB in Gloucester and we can trade plastic spheres.

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Hey OP, looking around various forums I came across this:

 

http://mackila.com/airsoft/atp/

 

Now, there is ALOT of info there, but I believe he mentions in section XB (10B I guess) the sort of calculations you are asking for. While he uses it for a MED calculator, I figure the same numbers could be applied to find what you are looking for. Just replace A with B and so on. I read through a bit of it, but it is just too long for me to do at midnight, after just finishing a calc exam, and with 7am classes tomorrow... Goodnight for me.

 

Section XB:

 

http://mackila.com/airsoft/atp/10-b-01.htm

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