Servo Powered Catapult

Looking for a fun creative project? What about an easy to make catapult? Well, luckily for you, this project is both fun and easy if you have the correct materials. The Catapult we made is designed to launch after you enter certain values on your laptop. Pretty cool right? Now this sounds complicated but this guide will walk you through step by step. The end product is a about a foot long, half a foot wide, and a foot tall. We've included the option of a regular catapult in case you cannot obtain the servos or photon.

Supplies

1. Photon kit including at least one servo.
2. A computer to write the code.
3. One or multiple screws
4. Hot glue
5. Rubber Band
6. Scrap Wood (Measurements do not need to be perfect but we listed below what we used:
7. One base piece: 1 foot long, 1/2 foot wide, 1 inch thick
8. Two identical side pieces, should be thin and around 1 foot tall.
9. (Optional) Side connecting pieces: We did this for support but also added style!
10. One small piece that connects your two side pieces, this will be used to position the servo
11. a thin flexible piece at least 1 foot long, this will act as the launcher

Step 1: Creating the Base

To start the base, you need a bigger piece of wood that can support everything you are about to add. The base should be at least 1 foot long by 6 inches wide. The thickness of the wood should be at least 1/2 inch. Next is cutting the identical side pieces. They should be around one foot tall, 2 inches long, and about an inch wide. These are just the measurements we used and they are flexible. The sides need to be attached in the middle of the long sides of the base(see picture above for guidance). They can be attached multiple ways. We screwed them in through the bottom. However, they can also be attached with a nail gun or even hot glue if you have neither a drill or nail gun.

Step 2: Adding to the Catapult

The next step is adding onto the base of the catapult. One option is adding side connectors. This step is optional, but adds support to the catapult as well as some flair. You will need four very thin long pieces of wood. These pieces will attach the top of the catapult to the sides to make it look better. We would recommend using hot glue to attach these pieces(see attached picture). If you do use a nail gun or screws, be wary that both have the potential to split the wood since it is so thin. Next, you are going to need a piece that connects the two side pieces. The thickness and width can be any measurement, but the length must be the width of the base minus 2 times the thickness of the side pieces. If this sounds complicated we will explain more in depth. The width of our base was 6 inches and our side pieces were an inch thick. This would give us 6-2(1) which equals four inches. f you are still having trouble look at the pictures above for guidance.

Step 3: Setting Up the Photon and Servos

After the base is complete, you must set up the photon. If you do not have a photon, than skip to step five for the regular catapult. You need to open your photon and plug in into a computer. Once it is plugged in, you will need to open particle.io and set up an account. It's fairly easy and it will walk you through the steps of connecting your photon. Once connected, you need to write your code and wire the breadboard correctly. Above are diagrams of how to wire and write the code. After wiring, you can click on the IDE on the left dropdown menu. It gives you the space to write down the code for moving a servo. Once written, you can press flash on the code and it will transfer the directions to your photon.

You just created a function. To see your function click on console or the name of your device. The name is probably extremely long with numbers and letters unless you renamed your device. On the bottom left you will see something that says (Servo1pos) It will let you enter a value and press call. You can move the servo anywhere from 0 to 180 degrees so don't try putting in larger or negative numbers.

Step 4: Finishing the Catapult.

The next steps rely on positioning. Before you put the servo on the catapult you need to attach a long then flexible piece of wood to act as the launching arm. It does not matter the actual length as long is it is longer than one foot. We used hot glue to attach it and you will need to as well. The next step is gluing the servo onto the platform. If this sounds unclear refer to the pictures above. You may want to put popsicle sticks around the servo to hold it in place but this is not required. The final step is adding a holder on the arm of the catapult. This can be done using a small cut cup or adding some tape so that a marble or small ball can fit inside. Congratulations! You have now completed the Catapult. You can mess around with the degree values on the function until your catapult launches just right. If your servo is not very fast your catapult may only launch 10-15 feet. If you want a farther launching catapult, skip to the next step. If you are interested in texting your catapult to launch, go two slides. Thank you for reading. We hope your product turned out well.

Step 5: Catapult Without Servos

If you haven't obtained a photon or you're just looking for an easier version, than you have come to the right place. The next few steps are very simple. First you need to drill a screw into the bottom of your base. Next, you're going to need a long, thin flexible piece of wood to act as the arm. You're going to glue part of the rubber band to this piece of wood. The other part of the rubber band will wrap around the screw in the bottom of the base. This will create tension as you bend the arm back causing it to launch farther. Lastly, you need a stopper. The measurements on the stopper do not matter as long as it blocks the arm from not going to far. See the picture above for more guidance. The stopper just needs to block the arm from overextension. You're almost finished! All you need now is a small cup or holder to glue to the arm. The cup/holder can be a different size depending on what you are trying to launch. Now all you have to do is sit back, bend back, and watch it fly!