SpudFiles Wiki - User contributions [en]

IPLA

2008-05-24T04:54:05Z

Carlman:

IPLA - The International Potato Launching Association

The IPLA is a very informal association of Spud Launching enthusiasts around the world. Its membership can be counted as membership of the forums at [http://www.spudtech.com spudtech.com] and [http://www.spudfiles.com spudfiles.com]. UK members can be found mainly at [http://www.uksgc.co.uk uksgc.co.uk].

Competitions and meets are often arranged under the banner or the IPLA.

IPLA

2008-05-24T04:53:31Z

Carlman: changed .com to .co.uk

IPLA - The International Potato Launching Association

The IPLA is a very informal association of Spud Launching enthusiasts around the world. Its membership can be counted as membership of the forums at [http://www.spudtech.com spudtech.com] and [http://www.spudfiles.com spudfiles.com]. UK members can be found mainly at [http://www.uksgc.com uksgc.co.uk].

Competitions and meets are often arranged under the banner or the IPLA.

Legal issues

2008-02-06T03:13:18Z

Carlman: /* Australia */

==United States of America==
===Letter from the ATF===
The bureau of alchohol, tobacco, and firearms sent the [[SGTC]] the following letter.
Another version with pictures can be found [http://www.spudfiles.com/Other/are_they_legal.php here].

<blockquote>
Department of the Treasury

Bureau of Alcohol, Tobacco, and Firearms

Washington, DC 20226

As defined in section 921(a) (3) of Title 18, United States Code (USC) the term "firearm" means --

* (A) any weapon (including a starter gun) which will or is designed to or may readily be converted to expel a projectile by the action of an explosive;
* (B) the frame or receiver of any such weapon;
* (C) any firearm muffler or firearm silencer; or
* (D) any destructive device. Such term does not include an antique firearm.

As defined in 26 USC subsection 5845(f) (2) the term destructive device includes any type of weapon by whatever name known which will, or which may readily be converted to, expel a projectile by the action of an explosive or other propellent, the barrel or barrels of which have a bore of more than one-half inch in diameter, except a shotgun or shotgun shell which the Secretary or his delegate finds is generally recognized as particularly suitable for sporting purposes; and (3) any combination of parts either designed or intended for use in converting any device into a destructive device as defined in subparagraphs (1) and (2) and from which a destructive device may be readily assembled. The term 'destructive device' shall not include any device which is neither designed nor redesigned for use as a weapon; any device, although originally designed for use as a weapon, which is redesigned for use as a signaling, pyrotechnic, line throwing, safety, or similar device; surplus ordnance sold, loaned, or given by the Secretary of the Army pursuant to the provisions of section 4684(2), 4685, or 4686 of title 10 of the USC; or any other device which the Secretary of the Treasury or his delegate finds is not likely to be used as a weapon, or is an antique or is a rifle which the owner intends to use solely for sporting purposes.

It is unlawful for anyone to make or possess a destructive device which is not registered in accordance with the provisions of the National Firearms Act.

We have previously examined that certain muzzle loading devices known as "potato guns." These potato guns are constructed from PVC plastic tubing. They use hair spray or a similar aerosol substance for a propellant, and have some type of spark ignitor. We have determined that these devices, as described, are not firearms provided that they are used solely for launching potatoes for recreational purposes. However, any such devices which are used as weapons or used to launch other forms of projectiles may be firearms and destructive devices as defined.
</blockquote>

===Interpretation of the ATF letter===
"other forms of projectiles" is typicaly interpreted to mean flammable, and/or explosive projectiles; ie, that "potatoes" were an example of an acceptable projectile, and not the only option.

===State, County, and City laws===
These vary. It is generally illegal to shoot a spudgun inside city limits.
The owner of the SGTC provides the following advice: "If it is OK to shoot a shotgun in your particular location....you will have no problem with your spudgun."

*In Glendale, Arizona and Phoenix, Arizona combustion spudguns are considered firearms.
Subject: RE: potato gun legality
The legality of potato guns are as follows. If the potato is expelled
by the use of air it is OK. If any explosion occurred from gas, powder,
etc. it is illegal and cannot be fired. The "firearm" definition is
what dictates this.

==Other countries==

=== Australia ===

Information taken from my (Julz) posts on Spudfiles Forums. This information is as accurate as possible, however, may not be entirely correct as I did not speak to anybody of authority, I gained my information only from government web sites.

Please note, nowhere did I read that spudguns were definantly legal. Assumptions that they are legal are made on the basis that in a detailed list of prohibited weapons spudguns were not mentioned.

I am not responsible for any trouble you get into as a result of this information.

For the original posts, see [http://www.spudfiles.com/forums/viewtopic.php?p=1305&lighter=&#1305 here]

Victoria----> Legal with a firearms licence. Pneumatic spud guns require a Category A firearms licence (they are classified as air rifles), whilst combustion spud guns require a Category E firearms license.

New South Wales---->Illegal - Requires a permit that cannot be gained without a legitemate reason for possessing the cannon.
Quote:
Item 2(3) Any device that is designed to propel or launch a bomb, grenade, rocket or missile by any means other than by
means of an explosive, including a device known as a PVC cannon.

http://www.police.nsw.gov.au/__data/assets/file/5232/Prohibited_Weapons_General_Permit.pdf

Australian Capital Territory---->Legal? - I could find no referance to spud guns etc in this page, detailing prohibited weapons.
http://www.legislation.act.gov.au/b/db_14541/19960829-16540/pdf/db_14541.pdf

South Australia---->? I could find no referance to spud guns etc in this page, detailing prohibited weapons.
http://www.sapolice.sa.gov.au/firearms/prohib_weapon/weapon_type.shtml

Northern Territory---->Illegal

Western Australia----> A spud gun can be constructed and possessed legally, however according to state police it is not in the publics interest for one to own a spud gun, so it will be taken and destroyed with no charges.

A spud gun cannot be registered although it does fall under the firearm classification.

Queensland----> Combustion Launchers,Illegal in all forms.Home made devices not registrable.

Pneumatic Launchers,Can be legally owned as long as used in safe manner,police have right to confiscate at anytime and without reason.

http://www.spudfiles.com/forums/australian-spudgun-laws-t7419.html

Tasmania---->Unknown I could not find any page detailing what weapons are prohibited.

update on 2006/02/04 by Mountaineer
Under Australian Law, a spud gun would be considered either a Compressed Air Gun (Class 'A') or a Muzzle Loading Firearm (Class 'B') depending on the propellant being used in the individual device.
This is something of a moot point however as any home-made firearm falls under Prescribed Firearms legislation.
Other examples of Prescribed Firearms include fully automatic weapons, modified firearms (sawn-off etc), silenced firearms, disguised firearms and firearms designed to fire explosive or incendiary devices such as bazookas and mortars.
There are a few exception to the Prescribed Firearms legislation, mainly related to weapons made and used in theatrical productions.
Theoretically, a registered gun owner with (for example) a Class 'B' license could have a gunsmith make a spud gun for them which could then be registered and legally used under purpose 2 (Target Shooting - unsupervised) of Australian law. However I find it hard to imagine anyone doing that when they could simply buy a "real" gun.
I got all this information from "Firearms & the Law in South Australia" (c) 2004 Regency Publishing ISBN: 1 86393 404 9 which I am currently studying for my own license.

[[category:Concepts]]

Camera flash

2008-01-05T05:42:13Z

Carlman: /* Triggered spark gap */

[[image:Camera flash.jpg|right|thumb|300px|Camera flash circuit]]
A '''camera flash''' can be used for spudgun [[ignition]] in several ways, either by itself or by feeding the high voltage from the flash capacitor through a step-up transformer (commonly an [[ignition coil]], [[flyback circuit|flyback transformer]] or a mains transformer in reverse).

The main advantage of camera flash-based ignitions is that it can be built using cheap, readily available components. The spark is more powerful than that of a piezoelectric ignitor. A camera flash is usually powered by one or two AAA or AA cells. Disadvantages include several seconds of recharge time before the ignition can be triggered again, and significant shock hazard from the storage capacitor if built improperly. Special care should be taken when used in metal launchers, as both sides of the storage capacitor can have significant voltages between them and other parts of the circuit, such as the battery poles and the trigger switch.

The camera flash is most easily obtained from a disposable camera, many places that develop films from these will give the discarded camera shell away for free if asked. The flash capacitor can store charge for a long time, and should be discharged before handling the circuit.

=Circuits=

There are several ways to connect a camera flash to a spark gap, which all have their own advantages and drawbacks. These are the most common circuits.

==[[Ignition coil]]==

An ignition coil (or other step-up transformer, such as a flyback or a mains transformer connected in reverse) will provide a high voltage spark when the flash capacitor is discharged through it. Most Ignition coils has a 100:1 winding ratio, meaning that for every 1 volt that is put into the coil, 100 volts come back out.

In order to modify a camera flash circuit for use with an ignition coil, follow these 6 steps:

 [[Step 1 - Removing the Flash Bulb]]

 [[Step 2 - Drilling the Holes for the Ignition Coil Wires]]

 [[Step 3 - Before Adding the Relay]]

 [[Step 4 - Adding the Relay]]

 [[Step 5 - Adding the Ignition Coil and Spark Strip/Spark Gap]]

 [[Step 6 - Providing Power to the Relay]]

 The flimsy battery holder can also be replaced with a plastic one, which is easily attained at any electronics store. Also, you can add a "kill switch" in [[series]] after the battery holder to cut off the power when the circuit is not in use. Be aware that the circuit is not "powered down" when the kill switch is in the off position. The circuit will not be able to charge, but the capacitor will still hold the electricity for a long time. The cannon will need to be "dry fired" after the kill switch is turned off. Be sure to point the cannon away from everyone when doing this.

 [[Step 7 - Removing the Battery Contacts]]

 [[Step 8 - Adding a Battery Holder and Kill Switch]]

 On a final note, the flash charging button on the front of the camera circuit board can also be replaced with an external one to add a finishing touch and an extra degree of safety. This step may be the hardest of all, as the margin for error when drilling the holes may be small. However, in the larger disposable flash cameras such as the [[Kodak Funsaver]] or [[Kodak Max]] cameras, the circuit board is larger and this is not an issue.

 [[Step 9 - Replacing the Charging Button]]

 The relay used in the diagrams is a standard [http://www.rowand.net/Shop/Tech/AllAboutRelays.htm 5-pin automotive relay], which can be purchased at any auto parts or electronics store. It is advisable that you also use a [[relay socket]], since it make the relay easily removable.

If a mains transformer connected in reverse is used, the spark gap will be electrically insulated from the rest of the curcuit, an advantage when used in metal cannons.

The output transformer from a stun gun can also be used, which can be useful if the charging circuit in the stun gun has died. These circuits are in fact quite similar to that of a stun gun.

{{stub}}

===Tube Switched Coil===

The ignition that requires the least modification of the camera consists of cutting one of the main leads to the flash tube, and connecting the ignition coil in between. Triggering the flash will produce a spark from the output of the transformer. The advantage to using the flash tube itself to switch the main discharge, is that almost any small switch can be used to trigger the circuit. If the trigger switch is replaced by a thyristor (SCR), the ignition can be triggered by an electronic circuit. The flash circuit itself is mostly intact and not driven out of spec, which means this circuit is quite reliable.

===Manually Switched Coil===

The flash tube can also be replaced by a heavy duty switch for triggering, though if the switch is too weak it may become welded shut. This switch will also be carrying the full voltage of the capacitor, and must be properly insulated to prevent electric shock. If the trigger switch is held down for a long time the charging circuit in the flash may break since its output is shorted for the duration.

==Triggered spark gap==

Another ignition method that does not require an external step-up transformer, consists of removing the flash tube, and taking out the trigger lead as well as the two main leads. These are then connected to three electrodes, which are placed together to form a spark gap of a millimeter or less. Triggering the flash will ionize the air in the gap and discharge the main capacitor. This produces a more intense spark than the first method, but it requires a more complex spark gap. The electrodes can also erode over time, requiring readjustment.

==Trigger transformer spark==

The trigger transformer for the flash tube produces a few kV on its own, and can be connected to a spark gap. The advantage to this method is that the main capacitor is not dumped, so recharge time is eliminated and it uses less battery power. The spark is very weak however, and this method is generally not recommended.

==Short circuit gap==

A camera flash can be used with a short circuit gap, which has movable points that can be brought in contact from outside the chamber. The flash capacitor is connected directly to the gap and creates a spark when it's shorted. This spark gap is more difficult to make, and may have isues with weldong and erosion, but is easy to hook up and requires little electronics knowledge.

==Others==

A camera flash can also be used to trigger [[sprinkler valve]] solenoids built for mains voltage, however the opening time will be brief since the flash capacitor is drained quickly.
[[Category:Ignition sources]]