soundclip of 30 bps blowback cycling (no paint yet)

[nerobro]

To address sound quality issues. First off this is an MP3 and therefore VERY lossy, especially at the far ends of the audio spectrum. Also this is a cheap microphone so loud noises cause some real issues with sound quality. ti's setup to reccord pi's voice properly, but fireing the gun is on an entirely different order of volume. I'll be helping him this weekend, maybe we can cut a higher quality reccording.

[Butterfingers]

Originally posted by 314159
this is the way i obtained the number 20ms.

i took a push button (single pole single throw, momentary, normally open) and took one lead connected it to +5v from my power supply. i connected the ground of the power supply to the ground of my storage ocilloscope. i connected the probe of the ocilloscope to the other lead of the push button. now when i press the button, you can see the line on the scope go from 0v to 5v. i positioned the switch on the marker (held in place by a lot of electrical tape) so that when the knob on the bolt was cocked back, it would press the button. when i fired the marker, it would let go of the button, and press it again when it went to recock. the time that the button was not pressed was 20 milli seconds. (measured on the storage scope)

Yes that is for one cycle.

If the system can't flow enough air to handle repeated shots you will get half cycles.

[314159]

Originally posted by Butterfingers
If the system can't flow enough air to handle repeated shots you will get half cycles.

the sound of the shots appear to be evenly spaced, and the hammer caught on the sear after every string of shots.

http://www.speakeasy.org/~aaronw/30bps.wav

uploading right now, throwing the link in so i don't have to post when it is done

[Cristobal]

Originally posted by nerobro
To address sound quality issues. First off this is an MP3 and therefore VERY lossy, especially at the far ends of the audio spectrum. Also this is a cheap microphone so loud noises cause some real issues with sound quality. ti's setup to reccord pi's voice properly, but fireing the gun is on an entirely different order of volume. I'll be helping him this weekend, maybe we can cut a higher quality reccording.

Yeah the mp3 format and a poor mic would do that. Just for kicks, I looked at the vocal section the speech analysis program Praat -- I'm used to seeing nice full .wav files in there for linguistics analysis but for this one the spectogram was the splotchiest I've ever seen, though it was certainly still possible to read the formant structures. I'll have to look at the wav that was just posted.

EDIT: I just looked at the latest wav file; it still isn't very pretty but I can guess where the shots fall. If I'm reading the waveform correctly it looks like a period that varries between .030 and .035 seconds. The max amplitude, however is consistent throughout, which probably implies good things for your consistency.

[wimag]

keep up the work. I for one am not mechanically inclined enough or patient enough for this type of project but it is people like yourself and Butters that push the envelope and open the eyes to others of FUTURE possibilities. Hey it is not like the first plane ever flew and they still have problems with cars (look at the recalls) so dont let anyone who is not going through this themselves to piss on your parade. keep it up!!!!

[nerobro]

butterfingers... you'll probally take this as an attack.... and it probally is. Stop obessing over half cycles. if the gun were half cycling we wouldn't be posting data. Credability is important. especially on this forum.

maybe this is just me being upset for doubting me on the kingman forum. it's time you take it that we're not throwing bull around.

[Butterfingers]

WOAH there,

Sombody seems upset.

I never took it as if you are throwing bull around. I was curious as of your techniques that you used to verify that you were getting a a full cycle. If you can't handle questioning and inquiry on materials and methods you shouldn't complain.

I have to say the fact that the gun had to be recocked every 1/2 second or so puts *some* suspicion into my mind.

My concerns are relevant and there has not been evidence that definitively proves otherwise. Thus a partial cycle *is* a strong possiblity.

My reasons being...

1) Free cycle oscilations follow a semi consistent frequency.

2) The fact that each shot varies between .030 and .035 seconds seems to follow this semi consitent pattern.

3) It *seemed* that I heard the sound of the gun being cocked happened every 1/2 second or so meaning either the sear did not lock correctly or it did not lock at all.

I have my reasons.

My question is how are you SURE that it is NOT partially cycling at 30 bps?

You have provided little evidence that rules out the strong possiblity of a partial cycle at high rates of fire.

How are you even sure yourself?

[314159]

easy nerobro

the gun did not really need to be recocked. when the gun stoped at the end of each string, it was in the fully cocked position. the hammer stuck on the sear, the sound you heard was me pulling the hammer back from the fully cocked position, and reaseating it on the sear.

my latest thoughts about why it is stopping at the end of the strings: the solenoid plunger has to drop almost all the way to release the hammer (too close for comfort). when the hammer sticks on the sear, the sear is stuck in the mostly down position. because of how the sear is set up, it has a little bit of play in it, allowing it to move left and right. if the sear would move off to one side a little, the solenoid would be unable to pull it down far enough to let the hammer go.....

it looks like i will be giving the sear a little luvvin tonight, breaking out the file and the fine grit sandpaper. i think that this should fix the problem.

[nerobro]

Quite simply the gun takes 20ms to cycle. The fact we can get it to cycle reliabily 35 ms apart means the gun is "resting" for 15 ms between cycles. If the gun were not fully cycling it would not be catching the sear. Again this issue was discussed in another thread. the gun IS fully cycling. A partial cycle would take less than 20ms. And the sear would not engage.

I can, and have handled the questioning. It's your insistance that the gun isnt' cycling that's really getting under my skin. You're stuck on that. And the gun IS fully cycling.

If our 20ms number were wrong, and the gun couldn't cycle at 30bps. the gun would be free cycling at that point, and would not catch the sear. And the gun would not be actually cycling at 30bps. it would be at some other number.

I would be the first one to admit that something isnt' working. I've just grown tired of this. Unless you want me to start with attacking your 30bps e-mag. How do you know it's fully cycling? You have no instrumentation setup to show that the bolt is traveling it's full length, or the AIR chamber is fully recharging.

With the spyder we measured how long it takes for the bolt to make it's full travel. that number is for all intents and purposes constant. Any rate of fire that takes LONGER than that number requires the gun fully cycle and rest on the sear for a period of time. If thats not fully cycling I don't know what is.

[Muzikman]

Hmm...I think someone pissed in Nerobro's cherrios this morning...

[Butterfingers]

Nero,

Seriously you need to calm down you are gonna have a stroke.

Nero, Im not claiming the gun ISNT cycling there just needs to be more definitive evidence out there to convice the public that it is cycling.

Nero, serously you have to stop thinking im out to "get you" im not. You seem to think that I am "Stuck" on somthing when I am in fact not. What I have noticed it that your attitude is very condescending.

If you are going to get upset over a few questions don't complain to me. Deal with it on your own time.

First off a partial cycle could or could not take more or less than 30 ms.

The period of oscilation of a spring is defined as:

T= 2(pi) (spring rate constant integrated with blow burst/mass of hammer assembly)^1/2

You can see the spring rates and mass can be varied to produce a particular period.

Am I saying you did this... absolutely not.

It seems to me that you think I am somehow ignorant to the fact that a spyder can do 30 bps and that *I* don't want to accept it.

The problem is that you don't like my objectivity. Like everything sceintific, I will accept it when emperical evidence is presented to me relinquises the physycally sound and logically relevant doubts I have in my mind.

If you would have told me that yes we have verified the stroke time for EACH shot, or even told me to look at the wave files and determine if in fact the first shot amplitude is greater or less than successive amplitudes. I would have looked at the information and said "hmm... looks plausable" instead I get attacked before I even get a chance to analyze the information.

All you have done is complain to me.

Go ahead question my 30bps e-mag. I can be sure my response will be a heck of alot more professional than what you have given me.

[nerobro]

Two forms of imperical evidence have been presented. First is the switch used to determine if the gun has fully cycled or not. Seccond is the fact that the gun IS catching on the sear at the end of each series of shots at 30bps.

I'm flipping out because this subject has been delt with in a previous thread. the gun IS cycling fully.

I like your objectivity, it's something that's rare. Rember back when you first questioned my statement that a spyder will cycle more than 40 times a seccond. I went out an got the data for you. that data suprised even myself.

What I don't like is the fact you re-question the data again and again. If you would like a paper on how to replicate our results.. I'm sure I coudl sit down with pi and present the paper to you. In fact.. I suppose that's somethign to do this weekend.

And yes I've had a bad day or two. and it's been enough to trip the switch on butterfingers. Butterfingers, what I'm asking is that you extend the same respect we extend you.

As I've shown in the past, I'm willing to back up my claims, but having to repeat the evidence half a dozen times isn't soemthing that makes me happy.

[shartley]

Originally posted by nerobro
Two forms of imperical evidence have been presented. First is the switch used to determine if the gun has fully cycled or not. Seccond is the fact that the gun IS catching on the sear at the end of each series of shots at 30bps.

[hitech]

Originally posted by nerobro
Two forms of imperical evidence have been presented. First is the switch used to determine if the gun has fully cycled or not. Seccond is the fact that the gun IS catching on the sear at the end of each series of shots at 30bps.

Maybe I shouldn't jump in here, but I will anyway. I haven't seen any evidence that the marker is cycling. The fact that you measured the time required to cycle once at 20ms and the fact that it is taking longer than that is NOT IMO solid evidence. There COULD be many reaons that it takes longer and still does not fully cycle under different circumtances. It very well may be fully cycling, there is just no way for me to tell, other than to take your word for it.

[314159]

Originally posted by shartley
but we on AO don't even take Tom Kaye's "word" on something of this type...

i am shure if tom kaye offered, many would drink the magic coolaid.

*sigh* if i had video equiepment, 30 fps video, of a marker firing 30bps, unless the frames synch up with the marker firing. you are not going to be able to tell the difference from 20 bps to 40 bps unless you focused on paint impacts, drawing a line or something.

i suppose i could whip up an optical sensor so i would not interfeer with the bolts travel to show a signal on the storage oscilloscope. but it would be impossible to show a string of shots in the sample window, and show detail in the readings. also without the time/division knob in the immage, as well as the variable timing knob in calabration, you could say that you had whatever rof you wanted by claming xxxx sweep rate. also, you would have to be able to intrepret the data to read it properly.

Originally posted by hitech
It very well may be fully cycling, there is just no way for me to tell, other than to take your word for it.

sensors can be placed in other areas than where they are said to be, video, images, and audio can all be edited, sometimes your preception cannot be trusted. in the end, what prof do you have of anything? this would could just be a dream, and no one would know the difference.

in the end, there is no data that anyone can post that can be 100% concrete. even if it is something as simple as saying that i am wearing pants.... right now i am going to put my time into my projects, and let the unbelivers fall where they may.