PHYS S-12 : Dan's Documentation
Final Project: RC Hot Air Balloon
My final project is a remote controlled hot air balloon with sensors on board. Click here to see my hot air balloon interface page, which I used to control and monitor the balloon.
To see my full process, including code snippets and indepth explanation of everything I did, go here.
I had planned for the helium balloons's bouyancy force to be equal to the weight of the load. Then I could use the hot air generated by my fire to lift the hot air balloon. Unfortunately, The hot air ballon can not yet freely go up and down. The fire I have doesn't raise the temperature enough; therefore it doesn't create enough bouancy force to make a difference in the ballooon's direction.
Electronics
On board the balloon, I had an esp32 feather, various input devices, and a servo motor. The esp32 feather is a great choice since it easily provides wireless transmission. Here's a list of the devices I used.
The IMU provided me with orientational data, the pressure sensor told me the balloon's altitude, the thermistor told me the temperature inside the envelope, and the servo motor controlled the hot air by covering the fire.
In the future, I'd want to fix an issue with my sensors that didn't allow me to access the acceleration data.
Basket and Fuel
The small rectangular openings are for the wires of my electronics to fit through. I had originally designed four circular holes to accommodate the standoffs of my fuel container.
Sadly, since I used Isopropyl alcohol as my fuel, it had a chemical reaction with my 3D printed container and destroyed it. I replaced it with a less-ideal small teapot that I hotglued onto the basket.
I need to mold clay into a custom container in the future. This will be able to withstand the heat and also be big enough to provide a sufficient fire.
Envelope
The envelope was formed form a circle cutout of a mylar blanket. Mylar is extremely lightweight and has high heat retention.
The problem with mylar was actually one of its benefits: being lightweight. It is extremely floppy and gets out of shape with the silghtest wind. I plan on buying craft wires to shape my envelope in the future.
Networking
The networking is what I am most proud of. I utilized the esp32's Wifi module to connect via wan. I used firebase for a real time database and p5.js for my web interface. I had to learn all these things from scratch, and it was a very fun experience.
Here's my basic networking structure:
Improvements Needed
As I've touched on before, my project needs further improvements. The main issues are that the fire wasn't big enough and the envelope was floppy. I plan on fixing these in the future by molding wax into a bigger fuel container and using sculpting wires to give structure to the envelope. Stay tuned for updates to this documentation!