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ARchangel
Posted: Sun Feb 20, 2011 10:55 pm
by PVC Arsenal 17
Electro Pneumatic Revolver (EPR) proof of concept.
More pics and vids tomorrow... I'm exhausted.
-Mark
Posted: Sun Feb 20, 2011 11:01 pm
by Gaderelguitarist
Whoa.
Posted: Sun Feb 20, 2011 11:26 pm
by mark.f
Aww come on man. Seriously? A 320x240 picture and no explanation?
Why do you do this?
EDIT: I even tried opening your Photobucket account... private.
Posted: Sun Feb 20, 2011 11:29 pm
by PVC Arsenal 17
mark.f wrote:Aww come on man. Seriously? a 320x240 picture and no explanation.
Why do you do this?
I was merely attempting to hide the fact that the gauge was installed upside-down... this forum is full of critics.
Basically it's a 15-shot pneumatic revolver that uses a microcontroller to handle the firing and indexing sequence. CO2 powered, removable rotary clips, full&semi-auto capable... etc.
Posted: Sun Feb 20, 2011 11:37 pm
by mark.f
Nah, I was just remarking towards the fact you post a very mean looking cannon, but leave me tossing and turning in my sleep as I wait for the write-up tomorrow.
(From what I can see) it looks great. Can't wait for the write-up.
Posted: Mon Feb 21, 2011 12:42 am
by PVC Arsenal 17
This'll do some explaining while I finish stuffing the electronics in the foregrip:
http://s237.photobucket.com/albums/ff15 ... irtest.mp4
Posted: Mon Feb 21, 2011 8:05 am
by POLAND_SPUD
what does it use to drive the step motor? l293d?
the fact you post a very mean looking cannon, but leave me tossing and turning in my sleep as I wait for the write-up tomorrow.
I don't know if you have noticed but he does this all the time
Posted: Mon Feb 21, 2011 9:06 am
by django
wow!, looks fantastic!!! we eagerly await more info on this DAMN YOU
Posted: Mon Feb 21, 2011 11:59 am
by PVC Arsenal 17
POLAND_SPUD wrote:what does it use to drive the step motor? l293d?
the fact you post a very mean looking cannon, but leave me tossing and turning in my sleep as I wait for the write-up tomorrow.
I don't know if you have noticed but he does this all the time
No step motor actually, I decided against them due to their high power consumption. Inside the main pipe is a 6V electric screwdriver. It provides high torque for turning the barrels and offers a convenient hex socket for easy intallation/removal of the barrels. Indexing is performed by a limit switch. Each barrel hits one as it passes over the switch and the appropriate action is taken in the Arduino sketch (I.E. stop turning and fire).
The motor and solenoid are fired using two basic N-channel logic level MOSFET circuits from a separate battery. The motor was pulling about 3 amps and it was too much for the normal motor driver IC.
And sorry, I like being a pain in the ass...
Had it not decided to snow again, I would have the free time to take this thing outside for some shooting. Next weekend perhaps
Posted: Mon Feb 21, 2011 3:36 pm
by POLAND_SPUD
I decided against them due to their high power consumption
The motor was pulling about 3 amps and it was too much for the normal motor driver IC
hmm that's surprising... it's a geared motor, right?
Couldn't you use a small step motor? that would make more sense IMO
Posted: Mon Feb 21, 2011 3:59 pm
by PVC Arsenal 17
It's geared, yes. This approach was much simpler. I don't think a stepper would even have the torque to turn the assembly.
Full-auto uncapped dryfire:
http://s237.photobucket.com/albums/ff15 ... nt=fau.mp4
Posted: Mon Feb 21, 2011 4:53 pm
by jrrdw
When is the live fire coming? ROF? Did I miss that or your not sure??? Nice work!
Edit: Live fire next weekend maybe...
Posted: Mon Feb 21, 2011 5:55 pm
by irisher
Am I missing something or are your barrel(s) only a few inches long?
Posted: Tue Feb 22, 2011 6:39 pm
by PVC Arsenal 17
The barrels are four inches long, enough to fire Nerf darts. I'll be able to demonstrate that next time I come home from school, maybe this coming weekend.
Posted: Fri Feb 25, 2011 8:32 pm
by PVC Arsenal 17
EDIT: better video:
http://s237.photobucket.com/albums/ff15 ... IM0976.mp4
Here are some videos, excuse the crappy quality:
http://s237.photobucket.com/albums/ff15 ... nt=fa1.mp4
http://s237.photobucket.com/albums/ff15 ... 012021.mp4
As you can see there was not one misfire in either mode. The indexing is dead-on accurate. However, if the barrel assembly is put back on out of line with the air outlet, there is a "synchronizing period" of a couple shots before it gets back in tune. Once it is, though, it's consistent. I'm still working on ways to eliminate that problem but overall I can't complain about how well the whole system is working.
And of course a size comparison to my other toys:
Note the electronic guts sticking out... there is much refining left.