Capturing Bullet Speed

Sometimes it’s amazing how slow our sense of time is. We find [Maurice’s] bullet capture system a great example of this. A pair of IR sensors spaced two inches apart can capture and calculate the speed of a projectile. Couple this with a user-input distance from the sensor to the target and a microcontroller can extrapolate the exact moment to trigger a camera to catch a bullet in mid-air.

As with his other projects, all the details on how to build and use this system are available for your perusal.

20 thoughts on “Capturing Bullet Speed

  1. I love these! I have been wanting to make one for a few months now and I guess this is telling me that now is the time… quite unfortunate that he chose an arduino though.
    I think I’ll survive without one.

  2. This guy is seriously ripping people off. He sells these Camera Axe gadgets for 20$, while they are actually worth 3-4$ max.
    He’s selling a “Light Sensor” for 20$ when it’s actually just a piece of protoboard with a photodiode, a couple of resistors and an audio cable. Not to mention the thing is wrapped in electrical tape.

  3. Bobby: what are you talking about? He’s making a PCB and paying for his project research all while offering the plans online freely. If you want to build one cheaper he’s letting you do it. If you want the convenience of someone else building it for you then buy it from him. Where exactly is the rip-off?

  4. Bobby, you’re an idiot.

    1) Do you think a $20 costs more than $1 to make? Point being that if he sold them for parts cost, or even double parts cost, he wouldn’t make any money. I think this gadget is worth much more than $20. Discuss.

    2) If you think it’s expensive, buy it elsewhere.

  5. What Osgeld said. Make a better design at the same price or cheaper.

    Anyhow, I have my doubts that this would work (or that it would be practical) to use with a real firearm, I say this because it would be difficult to make the bullet break both beams and hit a target traveling any significant distance. If you shoot things from very close range you get a different outcome as well as more mess/danger possibility.

  6. I was also wondering about the practicality of this design. It looks like the bullet would have to pass really close to the board.

    That being said, this is extremely cool. It really is crazy that these things can happen so quickly. There are probably lots of good uses for something like this besides clocking bullets.

  7. The “$20” was a typo. I checked out the store and the Camera Axes cost $200.

    Note that the parts kits cost $95. Looks like the guy is hand-assembling them and charging premium prices.

    But whatever, who cares if it is like $60000… no one is forcing you to buy.

  8. He was bitching about the light sensor thingy, not the kit/build one.

    I find this a nice example what you can do with stuff like an Arduino, build, test using the standard board and then make a suitable pcb for the purpose intended.
    And if you do charge like 200 usd for something he’s selling as a kit for 100 usd then I’m very fine with it. He’s just *kind* enough to offer people who don’t have the skills/take the risk/know someone to also get this in their possession.I doubt he actually wants to make a lot of them by hand. I would not, there are more fun things in life and you’re not going to get rich on stuff like this.

    While I do not agree with the idea that all arduino stuff is worthless – some stuff is neatly done – , it might be indeed a good thing to start making a “weekly arduino projects” roundup in one post.

  9. Anyone else notice how the summary is careful never to mention the Arduino by name, and just says “microcontroller”?

    Guess that is the new way of sneaking them in. With any luck, members of the Arduino Assault Force will be too lazy to read the actual page and not notice. Especially when it is sitting between two other Arduino posts.

  10. @MS3FGX: No, wrong. There’s nothing Arduino specific about this. Yes, his example uses an Arduino, but if I were to use this sensor I would use an AVR. There’s nothing difficult about this interface, just make sure you do the math right and any controller can be used to connect with the jacks on the sensor.

    Plus, Arduino projects are great… I’m going to go look for a few more to share right now.

  11. I like the idea, and like what he is doing. However, I too doubt the ability of opto sensors mounted on a PC board to pick up bullets.
    There are chronographs specifically for measuring bullet speeds already. They are accurate and cheap, and they have tall spread antennae to shoot between so as to eliminate the need to literally graze a circuit board with a bullet.
    Could someone better at interfaces than I am simply strip the value from an existing off-the shelf chronometer to do the same thing? You could add a header to the board or even strip the value from the output sent to the chrono’s LCD.
    Could even just build a new camera trigger board using whatever radio frequency system a chrono already does.
    Million ways to skin that cat, all of them better than skimming along a bullet millimeters over a board. The bow shock of a supersonic bullet (most any bullet then) would shatter it anyway just from air pressure.

  12. Hi guys, I think the pcb design would work fine for real bullets. This sensor goes pretty close to the barrel of the gun so I don’t think you would hit the board with a bullet. I know I never had a problem with this and I use using a ball bearing that is larger than most bullets. If you mount a gun on a firm stand and line everything up I just don’t see it being a problem. That said there are screw terminals on the board so it’s trivial to add in some wires to move the IR emitter and transistor to a farther distance from the board.

  13. @ Maurice
    This will not work on real bullets. Your ball bearings may be much larger than a bullet but it doesn’t have the flame and burning powder erupting behind it. Lets not forget the shock wave from many bullets breaking the sound barrier. I just can’t see it holding up through all of that. Might work once or twice if you are lucky.

  14. By using sky screens like a chronograph, you might be able to adapt this sensor to look “up” the way a chronograph does. Most actually work by sensing the shadow of the projectile as it passes by. I used to 1st chrono BB’s years ago w/an old Chrony setup. That way I could be fairly sure I wasn’t going to trip the sensors directly w/a 230 grain circuit interrupter when doing it for real.

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