I recently had the idea to create a catapult, But not just any kind of catapult, an electronic catapult! I wanted something I could just sit it down hit some buttons and watch it do its thing without being to big.

This is what I came up with:

It is a little bigger than what I would of hoped but maybe I will make a smaller desktop/ office version soon.
It uses the Arduino as the brains of the operation and do note I'm still quite new to Arduino.
It use 3 servos to control tension, angle and trigger.
Tension and angle are controlled but two potentiometers.
The trigger is controlled by a push of a button which also resets automatically!
There is a extra button for Manual Reset if needed, As well as the on and off button (blue)
all powered by Arduino and a custom shield to run the servo without killing the Arduino

Let me show you how I build it so you can build your own!

Step 1: Materials and tools

First thing first, Sit down.
Grab some paper and draw what you want! This way you wont spend hours in the hardware store getting things you wont need.
My design is very basic, it uses a H shaped piece for the angle stopper and just a simple arm made out of a plank of wood that share the same pivot as the H piece.

Design yours how you want, even do a Google on some designs if you don't like mine.
I have listed some pictures to look at for ideas.
When you have your design and idea your going to need to get the stuff to build it out of, Now it doesn't have to be wood, I could be anything!
Try and keep it light to keep the work low on the servos.

I went down to my local hardware store and picked up a bunch of wood for around about $15 for this project.
Your also going to need basic tools, bolts and other junk depending on your own design.

<p>hola me podria facilitar las medidas de los materiales? muchas gracias</p>
<p>Hey,</p><p>Where did you get the springs from? I'am trying to do something similar to yours for a school project.</p><p>Thanks!</p>
<p>can you send me the code for this project?</p>
hey! I'm trying to make this for a school project. which Arduino did you use and which diode? thanks! (I have no idea what I'm doing)
The arduino I used was from freetronics but pretty much arduino would work. I would recommend the uno. The diode was a 1 amp 1n4004, these are very common. Have fun! -Travis
Hi! I just got one question and what type of spring did you use? Thanks
Whats exactly attached to the Arduino to create all of the ports?
How exactly are you powering this?
The power comes from a 9V 2A dc plugpack.
@UnusualTravis; Hi! You've taken Catapult Science to a whole new level! I've tweeted this. Cheers! : ) Site
Need this at our bunker. :P <br>I see that you have the servos running at 6v vs 5v. Is there a particular reason for that? <br>And where can I get some of those AWESOME buttons?
I used 6v vs 5v because Stall torque spec's are: 10.5kg/cm(4.8v),13kg/cm(6v), <br>I also got the &quot;AWESOME&quot; switches from my work at Jaycar electronics, but they are not cheap at around $15 each. But it was totally worth it.
the higher the the voltage the more torque it will have
Excellent setup, I like how organized everything looks.
nice job......... how far can it throw a tennis ball

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Bio: Sorry I have not posted in a while, Been pretty busy, Be back soon! I enjoy all things electronic, Its a great feeling when you ... More »
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