Chronograph - Revision history

Technician1002: Photo size fixed

2011-05-29T07:12:32Z

Photo size fixed

← Older revision		Revision as of 02:12, 29 May 2011
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	Sample photo showing Audacity at the cannon discharge. The pre fire hiss of the pilot is shown followed by the piston valve opening. The muzzle blast is the portion with a heavy negative shift due to the pressure front of the muzzle blast.		Sample photo showing Audacity at the cannon discharge. The pre fire hiss of the pilot is shown followed by the piston valve opening. The muzzle blast is the portion with a heavy negative shift due to the pressure front of the muzzle blast.

	~~I'll fix the photo file size later.. Work in process.~~
	[[File:Musket_discharge_799.png]]		[[File:Musket_discharge_799.png]]

Technician1002: /* High Speed Photography */

2011-05-29T06:41:24Z

High Speed Photography

← Older revision		Revision as of 01:41, 29 May 2011
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	== High Speed Photography ==		== High Speed Photography ==
	With the introduction of consumer grade high speed cameras, high speed video is now a reality. With a known camera frame rate and a reference for how far the projectile moved between frames the speed can be calculated with speed = distance/time.		With the introduction of consumer grade high speed cameras, high speed video is now a reality. With a known camera frame rate and a reference for how far the projectile moved between frames the speed can be calculated with speed = distance/time.

			A variation to high speed video is a high speed strobe. This must be done in the dark to prevent overexposure with the long camera shutter time.

	This composite was assembled from consecutive frames of the high speed video.		This composite was assembled from consecutive frames of the high speed video.

Technician1002: /* Sound Based Homemade Chronograph */

2011-05-29T06:37:05Z

Sound Based Homemade Chronograph

← Older revision		Revision as of 01:37, 29 May 2011
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	[http://talonairgun.com/softchrono/ SoftChrono] is a freeware Windows application specifically designed for using a microphone plus soundcard as a shooting chronograph.		[http://talonairgun.com/softchrono/ SoftChrono] is a freeware Windows application specifically designed for using a microphone plus soundcard as a shooting chronograph.

	Sample photo showing Audacity at the cannon discharge. The pre fire hiss of the pilot is shown followed by the piston valve opening. The muzzle blast is the portion with a heavy ~~positive and~~ negative shift ~~from~~ the pressure front of the muzzle blast.		Sample photo showing Audacity at the cannon discharge. The pre fire hiss of the pilot is shown followed by the piston valve opening. The muzzle blast is the portion with a heavy negative shift due to the pressure front of the muzzle blast.

	I'll fix the photo file size later.. Work in process.		I'll fix the photo file size later.. Work in process.

Technician1002: /* Sound Based Homemade Chronograph */

2011-05-29T06:35:04Z

Sound Based Homemade Chronograph

← Older revision		Revision as of 01:35, 29 May 2011
Line 38:		Line 38:

	Sample photo showing Audacity at the cannon discharge. The pre fire hiss of the pilot is shown followed by the piston valve opening. The muzzle blast is the portion with a heavy positive and negative shift from the pressure front of the muzzle blast.		Sample photo showing Audacity at the cannon discharge. The pre fire hiss of the pilot is shown followed by the piston valve opening. The muzzle blast is the portion with a heavy positive and negative shift from the pressure front of the muzzle blast.

			I'll fix the photo file size later.. Work in process.
	[[File:Musket_discharge_799.png]]		[[File:Musket_discharge_799.png]]

Technician1002: /* Sound Based Homemade Chronograph */ Added Audacity screen shot.

2011-05-29T06:33:29Z

Sound Based Homemade Chronograph: Added Audacity screen shot.

← Older revision		Revision as of 01:33, 29 May 2011
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	[http://talonairgun.com/softchrono/ SoftChrono] is a freeware Windows application specifically designed for using a microphone plus soundcard as a shooting chronograph.		[http://talonairgun.com/softchrono/ SoftChrono] is a freeware Windows application specifically designed for using a microphone plus soundcard as a shooting chronograph.

			Sample photo showing Audacity at the cannon discharge. The pre fire hiss of the pilot is shown followed by the piston valve opening. The muzzle blast is the portion with a heavy positive and negative shift from the pressure front of the muzzle blast.
			[[File:Musket_discharge_799.png]]

	== Magnetic Based Homemade Chronograph ==		== Magnetic Based Homemade Chronograph ==

Technician1002: /* Magnetic Based Homemade Chronograph */

2011-05-29T06:08:29Z

Magnetic Based Homemade Chronograph

← Older revision		Revision as of 01:08, 29 May 2011
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	When using magnetic pick up coils and either a magnetic projectile by embedding a small magnet or detecting a ferris or non ferris projectile by detecting a disturbance in a static magnetic field, the time to cross between the two pick up coils can accurately measure a passing projectile's speed. This was used by a Spudfiles member with multiple pickup coils on a plastic barrel to measure the projectile acceleration and fall off of acceleration for the purpose of optimization of a barrel length for maximum launch velocity. The signal from the pick up coils can be fed to a sound card for measurements the same way it is done for the home made optical pickup.		When using magnetic pick up coils and either a magnetic projectile by embedding a small magnet or detecting a ferris or non ferris projectile by detecting a disturbance in a static magnetic field, the time to cross between the two pick up coils can accurately measure a passing projectile's speed. This was used by a Spudfiles member with multiple pickup coils on a plastic barrel to measure the projectile acceleration and fall off of acceleration for the purpose of optimization of a barrel length for maximum launch velocity. The signal from the pick up coils can be fed to a sound card for measurements the same way it is done for the home made optical pickup.

	An advantage of magnetic is immunity from wadding, sabots, and muzzle condensation or blast causing detection errors in an optical gate. Another advantage is the ablility to measure speed inside a barrel or measure valve motion to record valve opening times. Using more than 2 pickup coils the ability to measure changes in speed ~~is possible~~.		An advantage of magnetic is immunity from wadding, sabots, and muzzle condensation or blast causing detection errors in an optical gate. Another advantage is the ablility to measure speed inside a barrel or measure valve motion to record valve opening times. Using more than 2 pickup coils provides the ability to measure changes in speed.

	Disadvantages include complexity in eliminating radio frequency interference, magnetic pickup from motors, transformers, etc and setting the gain correctly to prevent clipping or distortion of the signal. Another disadvantage is the need to use either a magnet in the projectile or use a bias magnetic field and a conductive projectile.		Disadvantages include complexity in eliminating radio frequency interference, magnetic pickup from motors, transformers, etc and setting the gain correctly to prevent clipping or distortion of the signal. Another disadvantage is the need to use either a magnet in the projectile or use a bias magnetic field and a conductive projectile.

Technician1002: /* High Speed Photography */

2011-05-29T06:03:25Z

High Speed Photography

← Older revision		Revision as of 01:03, 29 May 2011
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	== High Speed Photography ==		== High Speed Photography ==
	With the introduction of consumer grade high speed cameras, high speed video is now a reality. With a known camera frame rate and a reference for how far the projectile moved between frames ~~and~~ the speed can be calculated.		With the introduction of consumer grade high speed cameras, high speed video is now a reality. With a known camera frame rate and a reference for how far the projectile moved between frames the speed can be calculated with speed = distance/time.

	This composite was assembled from consecutive frames of the high speed video.		This composite was assembled from consecutive frames of the high speed video.
	~~Note this edit is a work in progress please be patient as I fix the photo.~~
	[[File:Tumblecomposite.jpg]]		[[File:Tumblecomposite.jpg]]

	[[Category:Tools]]		[[Category:Tools]]

Technician1002: /* High Speed Photography */

2011-05-29T06:01:52Z

High Speed Photography

← Older revision		Revision as of 01:01, 29 May 2011
Line 62:		Line 62:
	This composite was assembled from consecutive frames of the high speed video.		This composite was assembled from consecutive frames of the high speed video.
	Note this edit is a work in progress please be patient as I fix the photo.		Note this edit is a work in progress please be patient as I fix the photo.
	~~http~~:~~//www.spudfiles.com/spud_wiki/images/d/d1/~~Tumblecomposite.jpg		[[File:Tumblecomposite.jpg]]

	[[Category:Tools]]		[[Category:Tools]]

Technician1002: /* High Speed Photography */

2011-05-29T06:00:20Z

High Speed Photography

← Older revision		Revision as of 01:00, 29 May 2011
Line 62:		Line 62:
	This composite was assembled from consecutive frames of the high speed video.		This composite was assembled from consecutive frames of the high speed video.
	Note this edit is a work in progress please be patient as I fix the photo.		Note this edit is a work in progress please be patient as I fix the photo.
	http://www.spudfiles.com/~~forums~~/~~files~~/~~tumblecomposite1_171~~.jpg		http://www.spudfiles.com/spud_wiki/images/d/d1/Tumblecomposite.jpg
	[[Category:Tools]]		[[Category:Tools]]

Technician1002: Added High Speed Video to the list.

2011-05-29T05:53:49Z

Added High Speed Video to the list.

← Older revision		Revision as of 00:53, 29 May 2011
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	Each pair of peaks represents a single BB passing over the two photo detector gates. The gates were three inches apart and the first gate an inch or two from the gun's muzzle. The velocity of each BB is calculated as the time between peaks (in seconds) divided by the distance between the two gates. Based on this recording, this particular BBMG is firing at about 330 FPS (the velocity varies from round to round) and with a rate of fire of ~4800 rounds per minute.		Each pair of peaks represents a single BB passing over the two photo detector gates. The gates were three inches apart and the first gate an inch or two from the gun's muzzle. The velocity of each BB is calculated as the time between peaks (in seconds) divided by the distance between the two gates. Based on this recording, this particular BBMG is firing at about 330 FPS (the velocity varies from round to round) and with a rate of fire of ~4800 rounds per minute.

			== High Speed Photography ==
			With the introduction of consumer grade high speed cameras, high speed video is now a reality. With a known camera frame rate and a reference for how far the projectile moved between frames and the speed can be calculated.
			This composite was assembled from consecutive frames of the high speed video.
			Note this edit is a work in progress please be patient as I fix the photo.
			http://www.spudfiles.com/forums/files/tumblecomposite1_171.jpg
	[[Category:Tools]]		[[Category:Tools]]