This Instructable will teach you how to build an air cannon that can be triggered with a switch. This cannon is capable of shooting projectiles, such as oranges, or parts of a potato very far distances, and at very high velocities. At 60 PSI, this device is able to shoot a small orange at ~77 mph with a range of ~500 feet.
While making this Instructable, make sure to have plenty of ventilation, preferably working outside. Also, wear gloves if you are worried of getting PVC cement on your hands.
Air cannons are capable of shooting projectiles at very high velocities. THEY ARE NOT TOYS!!! Never fire an air cannon at any person, or living thing as this could possibly injure or kill someone. When firing, make sure you are in an open field, or a place where the projectile has absolutely no chance of hitting someone, or someone's property that isn't your own. If you are under 16, then make sure to have an adult nearby when firing. Make sure to use common sense when firing, and don't do bad things with it. I nor Instructables take any responsibility for anything you do with this cannon.
Step 1: Materials
Here is a list of the materials you will need:
PVC parts (make sure all PVC parts are PRESSURE RATED )
1. 1 - 4' length 2" diameter PVC pipe (~$4.16)
2. 1 - 3' length 2" diameter PVC pipe (~$3.12)
3. 2 - 2' length 1" diameter PVC pipe (~$2.16)
4. 2 - 2" x 1" PVC bushing (~$1.35 each)
5. 2 - 3/4" PVC coupling (~$0.20 each)
6. 2 - 1" PVC elbow (~$0.51 each)
7. 2 - 1" PVC threaded adapter (screws into sprinkler valve) (~$0.74 each)
8. 1 - 1" FNPT threaded in-line sprinkler valve 24 volt >100PSI rating (I used this one: http://www.lowes.com/pd_50552-74985-57101P_0__?productId=1186963&Ntt=orbit+inline) (~$11.53)
9. PVC cement can (such as Christy's Red Hot Blue Glue) (~$4.37)
10. PVC purple primer can (~$4.00)
11. 3 - 9 volt batteries (~$1.00 each, but usually can be found around your house)
12. A new or broken bike tube (all you will need is the bike pump input) (~$2.00)
Drill and 1/4 drill bit
Total cost, if you don't have any of these parts, and excluding tools, adds up to ~$40, but if you already have pvc primer, pvc cement, batteries, bike tube, and/or any other parts, then it should be a bit cheaper