Step 1: Items Needed.
1) 5" section 1" sch40 pvc
2) 2" sec. 1" sch40 pvc
2) 90 degree 1" elbows slip to slip (s/s)
1) 1" coupler s/s
1) 1" thread adapter slip to thread female (s/tf)
1) 1" threaded male plug
1) 1" s to 1/2" tf reducer
1) 5 1/2" sec. 1/2" sch40 pvc
1) 1 1/2" sec. 1/2" sch40 pvc
1) 90 deg. 1/2" elbow s/s
1) 90 deg. 1/2" elbow s/tf
1) 1/2" end cap
3) ball point pens like the ones shown
1) 8 AA battery holder
1) shrader valve (I like the metal ones)
1) 1/2" 12volt solenoid valve (straight ports)
1) piezo buzzer rated around 12 volts
1) SPST rocker switch
1) 12volt single channel remote switch
1) 9volt battery plug
2) crimp on plugs
Some light gauge wire
Spray paint of your choice
8) AA batteries
Pvc cement and primer
Wire end crimpers
Soldering iron and wire
Step 2: Air Tank
Take the threaded plug and drill a hole to fit the shrader valve. Apply silicone sealant to the stem of the valve and insert it into the hole from the inside of the plug. If your valve has a nut, tighten.
Wrap Teflon tape around the threads of the plug and screw on the plug to the air tank. Paint and set aside.
Step 3: Barrel
Heat the 5 1/2" pipe section and slightly bend the pipe.
On the outer curve of the pipe, mark a line down the center. Mark off 6 equal sections along the center line. The marks I made on the side of the pipe are reference lines to show what angle to drill each hole. The outer most holes get drilled at the most extreme angles. Notice the angle of the tubes in the last photo. These are the angles to drill the holes at. The angle lessens as you move inward. Drill the 6 holes in the pipe to fit the pen tubes.
Disassemble 3 pens and cut off the closed ends and cut the tubes in half. Take the writing end part and cut off the straight part, cut that into 4 short sections till you have 6 pieces. Put one short cut off into one end of each tube and super glue them in place.
Insert a tube, glued piece first, into each hole you drilled earlier.
Use super glue around the base of each tube to hold them in place.
The barrel is made this way to cover as much area as possible while still remaining compact.
Paint and set aside.
Step 4: Electronics
I have 2 types of remote switches shown. We will use the +, -, NO (normally open), and the COM (common). The first one is a two channel switch (I'm using that one for this instructable, not for any reason) so NO2 and COM2 will not be used. The second switch shown is s single channel switch. NC (normally closed) is not used. If you hook this up, when the mine is turned on, it will go off immediately and turn off when the remote button is pressed. You don't want that unless you want to blow yourself up!
To start, take the 9volt plug and solder the red wire to one post of the SPST switch and another red wire to the other post. On the end of the second red wire, splice in another short price of red to it for a jumper wire. The end with the splice goes into the + port, then the short jumper wire goes into the COM port.
Get the piezo buzzer and spice in a piece of wire (I'm using green wire) on the red wire of the buzzer or the positive side if there are no wires (if no wires, run a wire to it). Crimp a plug on the end of the green wire. At the splice of this, put in the NO port of the remote switch.
Take a piece of wire (I'm using black) and crimp on a plug to one end. Splice the other end with the black wire of the 9volt plug and the black wire from the buzzer. Insert the splice into the - port.
The wiring is done. Put the remote switch into it's enclosure and twist the wires together to keep things neat and clean as shown.
Step 5: Final Assembly
Screw on the air tank on the side the arrow points away from (<-- air tank). Now would be a good time to pressurize the tank and check for leaks in a bucket of water. If you have leaks at the pvc joints, try applying super glue to the joint, wrap some type of fabric thread around the joint and apply more super glue and let dry. If leaking happens at any screw joint, apply more Teflon tape or seal with some silicone sealant.
Take the 1/2" 90deg s/tf elbow and screw it to the other side of the valve (elbow <-- air tank). Assemble the rest of the barrel.
Hook up the crimp on plugs to the 1/2" valve (it does not matter which plug goes to which post, it just needs power to it)
Put batteries in the power pack and tape it on the mine in a tight space. Plug in the power with the 9volt plug.
Find a spot for the remote switch,master switch (SPST) and buzzer.
Adjust the barrel to an angle you think will shoot well.
Step 6: How to Use
Load bbs into the tubes and tape over the ends the keep the bbs in place.
Pressurize the air tank (for bbs, I fill to 100psi. I use a shock pump for mountain bike shocks).
The unit is ready to be deployed.
Find a hidden spot that has a clear place to shoot into. Place the mine with the tubes pointing in the direction of the opponent. Remove the tape covering the tubes and turn on the unit. Cover with camouflage if desired.
Move to a position overlooking the trapped area but still in range of the remote (test range before using).
When an opponent is in the blast radius, press the button and the mine will be triggered, spraying bbs at them and buzzing.
Hit the button again to stop the buzzing and save battery life.
If you hid the mine so well that you can't find it, hit the button and follow the buzzing sound.