I need a way to test bolt cycle speed

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  • magmonkey
    Mass Destruction
    • Oct 2001
    • 775
    #1

    I need a way to test bolt cycle speed

    Destructive Customs is working on our next marker, and we need a way to test the cycle speed of the bolt, it is a blow forward design

    my question is not being an electronics guru, how can i hook two sets of IR transmiters and recivers to a timer so when the bolt passes the first set it starts the time and when it reaches the second set it stops(this way I can verify a full bolt cycle)?

    if anybody has a way to do this or a better idea please let me know


    Alan
    DC
    Tags: None
    • AnthonyDStone
      Tie Dye Artist
      • Dec 2004
      • 681
      #2
      Maybe....

      Build a cut away version of the body of the gun and use a chrono of some sort.

      Tony
      :headbang: Stony :headbang: undefined

        Comment

        • undescriptive
          Battered and Bruised
          • Apr 2004
          • 279
          #3
          ummm, how about a strobe timer when the gun is firing full auto?

          that would allow you to get the time pretty accurately... I think

            Comment

            • RazorMonkey
              Registered User
              • Jul 2003
              • 289
              #4
              Destructive Customs is working on our next marker, and we need a way to test the cycle speed of the bolt, it is a blow forward design

              my question is not being an electronics guru, how can i hook two sets of IR transmiters and recivers to a timer so when the bolt passes the first set it starts the time and when it reaches the second set it stops(this way I can verify a full bolt cycle)?

              if anybody has a way to do this or a better idea please let me know


              Alan
              DC
              I used something that's exactly what you described in Physics last year... I'll try to figure out what that thingamajigger was called

                Comment

                • ScatterPlot
                  Not pop, it's all Coke
                  • Jan 2002
                  • 1960
                  #5
                  If you had a nice enough strobe light and an oscilloscope, you could fiddle with the rate of the strobe light until it appeared that the bolt was not moving (pick a point, full extent, not out at all, pretty much anywhere- but full extent would verify it was a full stroke and also would be easier to see). Once the strobe and gun are synched plug the output of the strobe into the oscilloscope and read off the divisions. You would probably want to run it through a transistor first though to make sure all the power ratings for the strobe don't break the scope.
                  AIM-bertmcmahan
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                    Comment

                    • athomas
                      Of course it works-its AGD
                      • Jan 2002
                      • 8039
                      #6
                      The strobe would show the cycle speed of the gun but not the actual bolt speed. I guess the strobe could be adjusted to look at any part of the cycle though. If you are interested in seeing if the bolt actually completes a full cycle, it will work.

                      You could use the IR transmit and receive to measure time/distance. You could also use a highspeed camera and film the bolt cycling either through a cutaway or down the feed tube. Highspeed cameras are very expensive so I would recommend the IR method for cost effectiveness.
                      Except for the Automag in front, its usually the man behind the equipment that counts.

                        Comment

                        • PatrickLee
                          ICD-Owners.Com
                          • Jul 2004
                          • 9
                          #7
                          Originally posted by RazorMonkey
                          I used something that's exactly what you described in Physics last year... I'll try to figure out what that thingamajigger was called
                          photogate.

                            Comment

                            • RazorMonkey
                              Registered User
                              • Jul 2003
                              • 289
                              #8
                              Yessssssss that's it

                                Comment

                                • Redkey
                                  Registered User
                                  • Jan 2002
                                  • 176
                                  #9
                                  depending on the hardware it can be simple

                                  I have a home made chrono that works just like this... the first gate starts the timer the second gate stops it. Although in mine the gates are only blocked for a very short amount of time and output a single pulse.

                                  It works something like this.... a 5 v pulse from the optical gate is sent to a flip-flop turning it on. While the flip-flip is on the counter on my DAQ card starts counting at a frequency of 10Mhz. The second gate sends a 5v pulse to the flip-flop turning it off which stops the counter. The difference between the start and stop counts tells the number of 10Mhz pulses that have been counted which gives you the time. Factor in the distance between gates and you get velocity.

                                  You could get by without the DAQ card and just use an two channel oscope that can capture wave forms. Each optical gate gets it's own channel... after both gates have been triggered you will have two sqaure waveforms on the screen. The difference between the start points of the gate outputs will tell you the time it takes the bolt to travel from one to the other. You could also do this with a single channel scope and a flip-flop although I'm not sure how the ff will handle a signal that comes on and stays on. I have been using pulses and it works just fine.

                                  Another idea... this is my favorite... build a circuit that outputs 5 volts when the first gate it triggered and shuts off when the second is triggered... a flipflop should do the trick. Then take this output and feed it into.... get this, the input jack on your computers sound card. Just make sure that the voltage being sent to the card is less than 5 volts and that there is a resistor to limit the current. If the card is setup correctly you can record at 44.1 Khz or so. That is 44,100 samples per second... or 0.0000227 seconds per sample. Should be plenty of resolution for your measurement.

                                  Anyhow... the sound card will record the pulse as a tick sound. Just open up the recorded .wav file in a sound editing program and you should be able to measure the length of the pulse. I have code that will convert the .wav file into a series of numbers so it can be plotted in Excel to measure the duration of the pulse. It's pretty cool stuff.

                                  If the circuit is built so it resets itself it should be able to run continuously and create a wav file that is a series of clicks. Then you can see how steady the cycle times are.... cross refernce this to the input pressure and you can have all kinds of fun

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