Let's start with the parts list and schematic. Parts:
Arduino
(2) Hitec HS-311 servo motors (Amazon.com)
(1) Hitec HS-645MG servo motor (high torque)--Amazon.com
(1) mini Servo YKS SG90 (Amazon.com)
(1) Two channel remote control toy--I got a car for $11.99 at a local pharmacy
(3) 5 volt relays--Jameco.com #139977 (these are polarized so that positive voltage on one coil lead causes it to pick up, but the other polarity doesn't; you can produce the same result with a 5 volt relay and a diode. Relays "B" and "C" only operate one at a time--based on the polarity provided.)
1/4" x 3 1/4" x .025 spring (available at Lowes)
(6) 12" servo extension cables
Spring from a ballpoint pen
4" lazy susan http://www.amazon.com/Capacity-Bearing-Turntable-Bearings-VXB/dp/B002TIKEQ6/ref=sr_1_2?ie=UTF8&qid=1372692771&sr=8-2&keywords=lazy+susan+4+inch
9 volt, 500 ma DC power supply
6 volt, 1 amp DC power supply
3D printed parts, design and print files at:
http://www.thingiverse.com/thing:110350
Wood, screws,paint, wire, jumpers
In this step by step tutorial I will be showing you how to make your very own Homemade Viking Catapult!
You will need 5 sticks that are are 4-6 feet long with a diameter of 1-2 inches. I am using 4 foot long sticks. The 2 shorter sticks you need will be 2-3 feet long also with a diameter of 1-2 inches. I am using 2 foot long sticks. You will need all of the items shown in the picture. You will also need something that will make a hole about 1/2 an inch wide, such as a drill.
This Instructable will show you how to create a small desktop catapult that can be made with a few supplies from around the office. Although it may seem there are a lot of steps, but don't despair each one is very simple and you will be launching paper balls and other desk junk in no time.
So the first thing we need to do is gather the proper supplies. So here's the list: