the warrior yeti
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the warrior yeti
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10:27 PM - Mar 19, 2009 #21

Thanks for the second video Pascal. Very interesting!

I'm not certain, but I think I see the dart nock sliding along the top of the hook. If you watch very closely, there is a white thing behind the hook, which may be where the wires are soldered on. In a few frames, just as the dart nock and atlatl hook are going across the dark moss on top of the wall, the dart nock moves up and over that shiny thing, and in the next frame the light goes off. Maybe the dart is sliding across the wires, keeping the light on? It seems to me, to definitely be the angle of the hook that causes the dart to leave.

-Devin
In farewell, and yet not in farewell, the Master handed me his best bow. "When you shoot with this bow you will feel the spirit of the Master near you. Give it not into the hands of the curious! And when you have passed beyond it, do not lay it up in remembrance! Destroy it, so that nothing remains but a heap of ashes."

Basketmakeratlatl.com
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fiddler49
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2:22 AM - Mar 20, 2009 #22

Paascal, I can see the red led much better but the moss on the rock wall doesn't help with seeing
the end of the atlatl and spear. Can you hang a sheet or tarp on the wall and zoom in just a little?
Looks like the angle of separation is always the same and no spring effect off the spur. cheers fiddler49
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PaleoAleo
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2:49 AM - Mar 20, 2009 #23

This is so cool! THe red led light works very well.

I wish several of us were there with you to help try different things. I like Mike's idea of making the background more of a solid color (maybe a nice dark gray color...just in the are where the separation is occurring. It would also be interesting to see more of the dart at the moment of separation - to see the flex, etc.

Thanks again Pascal. This is quite educational for all of us and quite entertaining too.

Tom
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Pascal Chauvaux
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6:46 AM - Mar 20, 2009 #24

Hi there!

I made several trials at another place. I thought it would be more visible, but I was wrong: too much light (sun) or the sky as background doesn't help. I will try to put something on the wall. More to come.

-Pascal
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almo
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2:53 PM - Mar 20, 2009 #25

Yes, I've always wondered about that. It does look like the spur top is doing the pushing at the end. Some suggestions to improve the prototype...

- use much finer wire, so that is conforms to the spur shape, or
- check into sick on, flat film wire
- add granulation to the wire (somehow... reostatic linear coil, with the wiper on the dart?) so that a set of small lights are calibarated to spur angle changes to release

just brainstorming. Good stuff. I really wonder, now, if my throw release so far in front. I thought all along is was at my shoulder because I'm working on the loose wrist techniques.
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the warrior yeti
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5:12 AM - Mar 21, 2009 #26

Awesome! I am looking forward to seeing what you come up with!

-Devin
In farewell, and yet not in farewell, the Master handed me his best bow. "When you shoot with this bow you will feel the spirit of the Master near you. Give it not into the hands of the curious! And when you have passed beyond it, do not lay it up in remembrance! Destroy it, so that nothing remains but a heap of ashes."

Basketmakeratlatl.com
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Pascal Chauvaux
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8:34 AM - Mar 21, 2009 #27

I will take part in an atlatl meeting on April 12th in the south of France (Labastide, where a magdalenian reindeer antler ibex atlatl was found). As it is easy to fit my system to any dart, I will ask the atlatlists to throw with my LED assisted atlatl and will film them. So, we will see if there are different dart release moments...

-Pascal
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Pascal Chauvaux
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10:54 AM - Mar 21, 2009 #28

He he, I am working on another experiment: to put a miniature sensor for compression measurement on a dart.

I am making progress. I already found the sensor and the analog to digital converter. I need to find how to transmit the data to my computer and how to display them (graphical plot).

At the beginning of this project, I asked an electrical material seller if he had a complete kit for such a measure. The answer was a $3,000 digital force gauge (with a sensor, a RS-232 cable and a software). I decided to search for a cheaper solution. My father, who is a retired electrical engineer, told me he was sure to be able to make the converter and help me use the data.

So, it's coming. I will post videos asap.

-Pascal
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Paleoknapperjim
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3:42 PM - Mar 21, 2009 #29

Pascal, thanks so much for doing this experiment, you are a genius! I look forward to your continued experimental results. What I like about the videos is that they anyone can clearly see what is actually happening to the system without a lot of confusing discussin about physics and math.
Fiddler shared an interesting thought about the darts apparent flexing being the result of the darts rotation and it should be interesting to see if we can also resolve this.....thanks much....jim
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almo
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4:03 PM - Mar 23, 2009 #30

Pascal, you are really getting the groove on.

Have you thought about a wireless transmitter on the atlatl? There are tiny ones available (sorta spy ware) that can transmit digital data a few meters to your PC.
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the warrior yeti
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9:23 PM - Mar 26, 2009 #31

Hey Pascal, just wondering about the progress of your sensor experiment. Are you actually trying to measure the force between the dart and spur?

-Devin
In farewell, and yet not in farewell, the Master handed me his best bow. "When you shoot with this bow you will feel the spirit of the Master near you. Give it not into the hands of the curious! And when you have passed beyond it, do not lay it up in remembrance! Destroy it, so that nothing remains but a heap of ashes."

Basketmakeratlatl.com
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Pascal Chauvaux
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7:01 AM - Mar 27, 2009 #32

Devin:
Yes, I am still trying to measure the force applied to the proximal end of the dart. There are two more factors I must pay attention to: the sensor has no calibration, and I need to add a time scale in the data too.

It's coming.

-Pascal
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TBAtlatl
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3:31 PM - Apr 19, 2009 #33

I have been thinking about how the force against the dart changes over time. A way to measure that may shed some light on how the atlatl works. This kind of measurement is beyond my primitive abilities but it might be something that someone with electronics experience could do. Comparing a graph of the change in pressure against a video taken in slow motion would give us a lot of information to digest. Thanks Pascal for your good work in atlatl experimentation.

Bob Berg
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PaleoAleo
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3:32 PM - Aug 28, 2009 #34

Just sending this back up top so we don't loose it. I'm going to put a copy of it in the atlatl video section for safe keeping too.

Tom
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ramsay12344
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8:10 PM - Sep 04, 2010 #35

Last edited by ramsay12344 on 6:51 PM - Sep 06, 2010, edited 2 times in total.
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