Texas Technicians Use Accelerometers to Plot Bullet Hits
Waterloo Labs is a group of engineers from National Instruments and other self-declared “nerds” from Austin, Texas. These folks conducted an interesting demonstration using electronic accelerometers to plot bullet impacts from a suppressed Ruger MKIII .22LR pistol. The accelerometers respond to vibrations caused when the bullets hit a drywall target backer. By triangulating data from multiple accelerometers, each shot’s exact point of impact can be plotted with great precision. These point-of-impact coordinates are then fed into a computer and super-imposed into a Flash version of the Half-Life video game (which is projected on the drywall board). The end result is being able to “play” a video game with a real firearm.
Do-It-Yourself Electronic Target System?
Now, we are NOT particularly interested in shooting Zombies in a video game. However, the technology has interesting potential applications for real shooters. Waterloo Labs has published the computer code, used to triangulate bullet impacts from multiple accelerometers. Potentially, a system like this could be built to provide display and scoring of long-range targets. Sophisticated electronic target systems already exist, but they use proprietary hardware and software, and they are very expensive. The Waterloo Labs experiment shows that shooters with some computer and electronic skills could build their own electronic scoring system, one that can be adapted to a variety of target sizes and materials.
In addition, we imagine this system could be utilized for military and law enforcement training. The walls of structures used for “live-fire” room-clearing exercises could be fitted with accelerometers so the bullet impacts could be plotted and studied. Then, later, the impact plots could be combined with a computer simulation so that trainees could “replay” their live-fire sessions, viewing the actual location of their hits (and misses).
Credit The Firearm Blog for finding this Waterloo Labs project.Similar Posts:
- Gun Science: Engineers Plot Shots with Accelerometers
- Electronic Target Systems — Seeing is Believing
- Electronic Target Systems — Fast, Precise, and Expensive
- New CMP-Approved Air Rifle and Rule Changes for Electronic Scoring
- High-Tech Target Systems Plot Shots Automatically
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Tags: Accelerometer, bullet, Computer, Half-Life, National Instruments, Plot, Target, Waterloo Labs
Sorry, but this is no more or less complicated than the technologies used in existing electronic target systems. Any hobbyist who can rig up an accelerometer-based system can just as easily create an acoustic system. Just replace the accelerometers with microphones. Existing target systems do use plenty of off-the-shelf hardware. They are expensive because of the limited size of the market.
I saw this and instantly thought that combined with the wireless video type of target monitor the system would be very good for letting you know where the projectiles hit visually with a flashing dot or something — useful if you have small projectiles or very beaten up targets
Exactly – in fact, in this application, the accelerometers are probably being used as simple piezo microphones. All you need to measure is relative travel time of the vibration from the point of impact to each mic, so you can just look for the rising edge of the “sound” pulse.
I wonder if they used a silenced pistol to prevent the drywall from ringing in the event the muzzle report arrived at the same time as (or ahead of) the subsonic .22LR rounds?
No matter how you do it, you still need a pile of calble if you’re going to make this work at 100yds or more! And the cost of all that electronics would buy you a pretty sweet spotting scope.
Dwight and Tony both raise some good points in their comments. However, consider that much past 600 yards, no spotting scope, no matter how large and expensive, can reliably distinguish bullet holes in the black. Even in the white, it’s hard to see holes at 700 yards in perfect conditions. The outputs from the accelerometers could be transmitted wirelessly to a receiver for processing with the computer.
Yes, an acoustic system would also work, but what is interesting here is that the Waterloo Labs crew has openly published the software that makes their accelerometer system work.
it is nice to see they published that information, but as a programmer that knows a little about audio and maths, its not that hard to see how they’ve done it, or how to replicate it with home made software
Yes – as soon as I heard about Oehler’s electronic target system, the solution was fairly obvious.
Adding wireless capability would be the next step, but a wireless camera gets the job done more easily and with more flexibility (use any target.)
Don’t get me wrong – it’s super cool – but it’s a science project, not a product.
There’s nothing stopping this technology from being affordable (in either the National Instruments or Oehler implementations) – it’s just more complicated than a remote camera system, at the same basic price point.
Yeah, they published the source for the project, but unfortunately it uses their $5k signal processing software suite and kilobuck ADC. Still, very cool, and very helpful place to start for building something yourself with cheaper components. But, for a target shooting application, you’ll need a more sophisticated time-difference-of-arrival calculation than they use.
neat gadget, but Dwight is right, a wireless camera works very well if there isn’t someone in the pits to score.
f-class you have someone scoring for you at target in the pits.
I’m sorry, but this technology has been in use for years by the weapons testing establishment. I have personally used subsonic (rubber membrane) and supersonic (bar/microphone) based systems for small arms, cannon and tank fired projectiles. A company making such instrumentation is MS Instruments in the UK, their ‘Chamber Target’ is a classic example of the above arrangement. Though it is excellent that thy have produced this, the fact that they have used drywall material may cause problems for a couple or reasons:
1) If the target is heavily used, the impact shock’s propagation through the now non-uniform perforated target will change.
2) The target’s sensor will require accurate measurement each time a target is (re)constructed, otherwise timing and hence target impact positional errors will occur.
EDITOR: Neil — interesting report — thanks. The Texas technicians weren’t claiming anything new in terms of the recording technology. What was innovative is how the sensor data was connected to the video game action rendering control so that live shots were plotted into the video game in real time.
What about projecting videos on the walls with the ability to score hits in a shoot house? Many, many different scenarios would be available.