Motor Powered Cardboard Trojan Horse
This is my project for the Autodesk Instructables Make it Move Design Challenge. I chose to create a Mini Trojan Horse Design out of cardboard and PLA, utilizing a Lego train motor to move forward by itself. The main ideas of the design I chose were to make a project that not only looked visually appealing, but was also cost efficient in the materials used.
The Trojan Horse was one of the first ideas I had in mind for a project theme as creating a design in its likeness wouldn’t be too expensive, and I could easily incorporate recycled components like a Lego train motor I owned. I also used placed a few Minifigures inside the horse as a reference to how the Greeks hid some of their soldiers inside the horse to win the Trojan War.
I also faced various challenges when I was building my project. When I created the trap door on top of the horse, I found difficulty in creating the trapdoor on the back of the horse as I couldn’t attach the hinge without the cardboard piece falling into the body. This issue was resolved by using Lego bricks to stabilize the cardboard in the position I wanted it, then using a piece of cardboard scrap inside the body to prevent the trapdoor from getting stuck. I feel like I could have tried to find a solution in order to make the hair and tail out of cardboard as well, but as it is right now, I feel like the alternative of using strips of black paper was sufficient enough for the tail but didn’t work so well for the hair. Thus, I didn’t add any hair as I believed the design looked better without it.
After completing this project, I don’t plan on submitting it to the actual Autodesk Instructables website for the contest. That being said, I feel like I still made a design that both adheres to the contest’s guidelines and successfully reached my 2 goals of making it visually appealing and cost efficient.
Steps I Took to Build my Project:
1) Design the horse body and parts on Fusion 360.
This is my design of the project in Fusion 360. Out of every other modeling application, I found Fusion worked the best for me. I started with the base before working my way up to the head, then designed the round pieces last.
2) Use a Laser Cutter to carve out the cardboard pieces.
The Laser Cutter is by far the best option to create the main horse body. I used cardboard as the main material for my pieces as it’s lightweight and easier to bend, but wood might work better for stability (though be cautious of its weight).
3) Use Flashprint 5 with a 3D printer to create the round pieces (nose and back of head) and the wheels.
The round pieces (which are the nose and back of head) will be difficult to create with just cardboard, so using PLA instead works as a solution to that. I recommend that the wheel holes are scaled slightly bigger than a Lego axle’s size, as the ones I made were just barely too small to fit on them. You can use any 3D printing preparation software, but for this I used Flashprint 5.
4) Construct the main body with cardboard pieces and attach together with glue.
With most of the pieces made, you should be ready to start the construction process. Build the main body starting with the head all the way down to the legs, and use glue to make sure your pieces stick together.
5) Attach a hinge to the horse’s back and a cardboard piece to the hinge to make a trapdoor.
The hinge I used was from a small wooden box from Michael’s, which I could easily unscrew and glue to the trapdoor piece. After gluing the trapdoor with the hinge to the back of the horse, I stacked Lego bricks inside the horse so the trapdoor wouldn’t fall through completely. To prevent you from not being able to open the trapdoor, you can use a keyring as a handle.
6) Cut out about 8 thin strips of black paper, glue them together to create a tail, then glue it all on the back of the horse.
Make sure the pieces aren’t too long, and slightly angle each piece when sticking them together so that most of them can be seen at once.
7) Drill out a hole at the bottom of the base to insert the motor, and glue it on.
The motor I used was from a Lego train set, and I needed a hole of about 6.8 mm in diameter to make sure I could fit the Technic pin and that the base was glued on flat.
8) Place battery pack at the top of the base, securing it in place with glued Lego bricks around it.
The set the motor came from had a battery pack and an IR receiver. Set the receiver to 1 before doing this step, then place the parts inside the base as shown in the image above. I placed gray Lego bricks around these parts to make sure they didn’t fall out when running.
9) Attach 2 wheels to an axle, placing it inside one of the motor’s holes, and repeating for the 2nd set of wheels.
Since my wheels didn’t fit a regular Lego axle, I had to substitute with Lego staff pieces instead. As long as you scale your wheels slightly bigger, you shouldn’t run into this issue.
10) (Optional) Place a few minifigures inside the body via trapdoor.
This step doesn’t matter much, but it can definitely add more emphasis to the size of the horse and as a reference to the hidden Greek soldiers in the original myth if you choose to add them.
11) Turn on the motor, and use the remote to test the movement.
Lastly, turn on the motor by pressing the on/off button on the battery pack and using the remote from the train set the motor came from to do a test run. If the remote doesn’t cause the motor to move, make sure the remote is set to 1 as well as checking if the axles were placed properly.