Thread: DIY Steel Plate Impact Detection

For a month or two I have been tinkering with this steel plate impact detection idea for when you go practising target shooting on your own. I found it sometimes difficult to hear a hit (earplugs) and to see the hit (recoil or dare I admit it - old age). I got it working and today I took it to a dog-walk park with my son and tested it all the way to 350m.

Here is a video of it working in my workshop: https://youtu.be/7acWxYwWrTg

50m test: https://youtu.be/jYXJJbm0JaI

100m test: https://youtu.be/ID9QplH6RR8

200m test: https://youtu.be/JgVao70CrxY

350m test: https://youtu.be/f0KK7jSD3as

I tend to over-think/over-engineer things, so what sort of range would one need to make it work at to be really useful - will 2 km be enough?

Any all ideas and feedback appreciated.

Potentially a good idea.

The only problems I can forsee are vibrations through the plate shaking the sensor too much leading to failure, and a projectile pass through causing the sensor to go beeeep-AAAAAGHH!

Originally Posted by Max Headroom

Potentially a good idea.

The only problems I can forsee are vibrations through the plate shaking the sensor too much leading to failure, and a projectile pass through causing the sensor to go beeeep-AAAAAGHH!

Yeah, good point. If the projectile pass through the plate it would definitely be a problem. Would maybe be a good idea to only use it at longer ranges when the projectiles won’t pass through anymore. Or better plates.

For the vibrations, I have experimented a bit with potting the electronics inside the enclosure. Will see how it holds up after taking it to the range.


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If it was 22 only, no problems I should think.

very clever Jan

i think with most sub-magnums, up to 1000m would be fine, it is very rare for us to shoot beyond that in gong comps

if you want to bring it up to kaitoke to do some destructive testing up to 200m I am happy to help. can shoot at it with 22LR, 223, 708 and 270

how does the sensor attach to the back of the plate ?

I've got one of the magnetospeed gong hit indicator lights, pretty neat system but I've never actually had to use it yet.

I find it easy enough to determine a hit out a fair long way, decent ring off the hardox plates and if I'm practising shooting a real long way off I'm normally up the hills killing little white rocks.

Originally Posted by ebf

very clever Jan

i think with most sub-magnums, up to 1000m would be fine, it is very rare for us to shoot beyond that in gong comps

if you want to bring it up to kaitoke to do some destructive testing up to 200m I am happy to help. can shoot at it with 22LR, 223, 708 and 270

how does the sensor attach to the back of the plate ?

I have tested the radios on their own and got just under 10km out of them. When the transmit radio is mounted behind the steel plate, the signal get attenuated so I am hoping that more than 1000m will be possible. Will do some more range testing.

Yip, will definitely bring it to kaitoke - just need to do a bit more testing on it first, then I will build a couple more and we can shoot them till they give up

The sensor is mounted directly on the pcb. I’ve drilled two holes into the plate (bought off trademe) and threaded them. So the pcb is fixed inside the plastic enclosure, and the enclosure is bolted onto the plate. Enough of a shockwave gets transferred for the sensor to trigger with a lightish hit with a hammer against the plate.


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Originally Posted by GWH

I've got one of the magnetospeed gong hit indicator lights, pretty neat system but I've never actually had to use it yet.

I find it easy enough to determine a hit out a fair long way, decent ring off the hardox plates and if I'm practising shooting a real long way off I'm normally up the hills killing little white rocks.

What sort of distances do you out to?


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Originally Posted by janleroux

What sort of distances do you out to?


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Beyond a 1000 yards im normally shooting rocks up the hills, as its just easier for me, ie no need to arrange with a land owner etc, no need to hang gongs.

My local range only accomadates 400 yards, but I've previously had no drama determine hits on steel to 1000 or so.

Depends what ya hitting them with tho I guess.

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Maybe do some tests with the sensor unit taped to the back using duct tape, or even epoxied on (probably too brittle for repeated shocks)

Unless the holes are blind, that would be a weak point. Even grade 8 bolts don't handle being shot with medium calibers...

Originally Posted by ebf

Maybe do some tests with the sensor unit taped to the back using duct tape, or even epoxied on (probably too brittle for repeated shocks)

Unless the holes are blind, that would be a weak point. Even grade 8 bolts don't handle being shot with medium calibers...

Interesting idea... Attaching the electronics to existing plates is a headache. If it full of rust or old paint then nothing sticks for very long. Yes, thanks - will try the duct tape idea. If it works, then it will be genius!


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Originally Posted by janleroux

Interesting idea... Attaching the electronics to existing plates is a headache. If it full of rust or old paint then nothing sticks for very long. Yes, thanks - will try the duct tape idea. If it works, then it will be genius!


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The magnetospeed hit indicator uses a double sided tape to attach to the back of plate

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We have had no trouble detected hits from 0-500yds and even out to 7-800yds with a big calibre. It’s from there out that it gets harder to detect, as the velocity drops off and there is less of a ring to the plate. From 7-800 and beyond the crew up on Taihape have a strobe light set up on a plate that works well, unsure how it’s attached though.

I like your setup

Originally Posted by Shootm

We have had no trouble detected hits from 0-500yds and even out to 7-800yds with a big calibre. It’s from there out that it gets harder to detect, as the velocity drops off and there is less of a ring to the plate. From 7-800 and beyond the crew up on Taihape have a strobe light set up on a plate that works well, unsure how it’s attached though.

I like your setup

Thanks @Shootm

I was thinking that the 1000-1500m range would be where it would come to life. So if it can work reliably up to 2000m, then 1500m is in the bag.

The other use I thought of was for some of the Plinking type competitions (if we want to promote shooting a bit more) - it will give people watching an instant confirmation on a hit (or miss).

Will try to do some 1500 - 2000m testing soon.


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Originally Posted by janleroux

Thanks @Shootm

I was thinking that the 1000-1500m range would be where it would come to life. So if it can work reliably up to 2000m, then 1500m is in the bag.

The other use I thought of was for some of the Plinking type competitions (if we want to promote shooting a bit more) - it will give people watching an instant confirmation on a hit (or miss).

Will try to do some 1500 - 2000m testing soon.


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Bring it up to the Toby shoot
Just out of curiosity what sort of cost to put that together?