Pumpkin Carriage

Can’t believe it’s already time to wrap up intro to fabrication. I’ve been having a lot of fun in this class and will definitely miss weekend/late night shop sessions. For my final project, I made a pumpkin carriage that will run (a little) when you place the pumpkin onto the button.

 

I got several mini pumpkins from apple picking a two weeks ago and have been wanting to do something with them. As soon as I learned about the assignment, I thought about powering up a pumpkin. My initial idea was to create a Cinderella-like carriage with a flying unicorn attached to the top. Due to time constraint, I had to scale down the decorative elements and focused on mounting the motors.

Thanks Ben for giving me this double gearbox!

It was a bit tricky putting them due to the scale but yet I was so amazed by how neat each parts are constructed.

After assembly the gearbox comes measurement time. I need two wheels attached to the motor’s metal shaft and two wheels attached to a free spinning shaft. The wheels need to have a tight fit to the shaft which requires two different central openings. The free spinning shaft is shaped as a rounded dowel while the motor shaft is shaped in hexagon. I measured all parts with a digital caliper and prototyped with cardboard before switching to acrylic. Due to different friction in materials that affects the fit, I had to modified my design several times at the laser.

Green tint acrylic wheels cut by the laser.

Noted the amount of failed wheels behind….

Birdseye view

Base

Assembly time!

Birdseye

Bottom

I was usually pretty confident with my measurements. However, I made more errors this time than before since building a moving object requires more attaching points and higher precision. The distance between the motor mount was a little off but luckily, I managed to lock it with tilted screws after minor expansion on one of the holes. I also didn’t think about the placement of battery before creating the base which left no room for me to mount the battery and had to double sided taped it to the motor.

Side

When you place the pumpkin onto the button, it powers up the motors. Unfortunately, the carriage will only move after brief second which I suspect the irregular shaped of the pumpkin and weight as causes. Ben warned me about the possibility of motors not powerful enough to carry a pumpkin yet they seem powerful enough that the button press is rather the issue.  I will bring in a slightly bigger and rounder shaped pumpkin tomorrow and hopefully it solve the problem and run longer!

If not, it still runs even if it’s just a little bit!

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