THE X-MAS GUN (X-GUN): 3 Stage Optically Triggered


Link to my main coil gun page.
Link to the high energy coil gun page.
Link to my homepage
Link to the permanent magnet repulsion coil gun page
Link to velocity determination circuitry, event timer

This is the X-mas gun because I was able to make it by using the gift certificate I got for X-mas from Gillian's mom-Thanks! It was for Fry's electronics, The most coolest bestest electronics store (way better than radio shack) I have ever been to.

X-GUN Coil Gun Specifications

PROJECTILE: Solenoid from small relay
BARREL: 5 mL clear plastic pipette tube stolen by Kurtz
COILS: Three layers of magnet wire from microwave fan; 1" length; approximately 2 Ohms of resistance
CAPACITORS: 410 uF @ 300 Volts for each stage from camera flashes. Total energy storage of 55 Joules.
CHARGER: Single transitor driven flyback transformer (rectified output)
SCR's: Silicon power cube 16A @ 1000 volts from Surplus Sales of Nebraska
MANUAL TRIGGER: SCR driven, manual start switch
ELECTRONIC TRIGGER CIRCIUTS: Modified restored beam; optical sensors
BYPASS DIODES: 16 A Diode housed in SCR power cube

Click here for the overall X-Gun schematic and here for the specification of all components.

Here is another veiw of the X-gun's guts:

Everything is housed in a galvanized steel electrical box I found in the trash in Golden Colorado. Everything is stuck in there with velcro squares so it is easily removable. The triggers are made on solderless breadboards so I can change the trigger circuitry with minimal hassle. Since the trigger circuits are also held in place with velcro squares, they can be independently moved up and down the barrel to adjust timing (as if I even needed it-Ha!). There is also an analog voltage meter to monitor the capacitor voltage while charging.

This gun is pretty fun to show off. When it fires you can hear three quick but distinct pops as the back of the barrel slaps into the metal case in recoil as each of the coils fire.

I used the high speed event timer to calculate the velocity of this coil gun. At a capacitor charge of 175 Volts, 1 coil pushes the projectile at a maximum velocity of 1.3 meters/second. Two coils gets me a max speed of 3.0 meters/second and all three coils shoots the projectile through the optic sensor in 3.3 miliseconds corresponding to a velocity of 4.9 meters/second and an average coil acceleration of 330 m/s^2. With a charge of 250 Volts on all three capacitors the maximum measured velocity is 8.0 meters/second or 18 miles/hour. Here is a photograph of the X-GUN getting measured for speed:

Here are a set of before and after photos of one of this coil guns shooting through some glass! Ok so it's not really shooting "through" the glass but it's breaking it anyway.

Last updated: 6/28/02
Copyright 2002, Greg Miller