If you're curious, above is a picture of our finished cannon.
The group is Aisha Baig, Nina Truong, Sierra Milhoan, Chris Evans and myself (whose name can be found above). The task was to create a cannon capable of launching projectiles (specifically of the smaller, spherical kind) to assorted distances, the values of which would be subject to our whims, and those of Mr. Twilley. The portfolio will cover our journey - failures and successes - step by step, until the end. I do not, however, personally believe that any amount of substance that could be produced in any media would ever truly express the sheer grandeur of this which has consumed almost half a year of our lives. Know that what you will see is but a fraction of our experience in room 126.
MATERIALS USED IN THE CANNON:
- 2 foot PVC pipe
- 1 foot PVC pipe
- PVC threaded adapters - one inch diameter
- PVC cap - two inch diameter
- PVC coupling - two inch diameter
- PVC bushing - two inch by one inch diameter
- 90 degree PVC elbow slip - one inch diameter
- sprinkler valve
- old bicycle tube
- devcon clear epoxy adhesive
- teflon tape
- PVC cement and primer
- 1/2" plywood
- (miscellaneous hardware)
- lots of wood
- cylindrical cookie container
Our Process by the Week
At the beginning, the first week to be precise, we were merely trying to figure out what we wanted in our design. Something simple yet effective was the essential idea. It did however take us much longer to actually find a design for the base.
When the second week started, we began work on the barrel stabilizer. We knew what the cannon itself would look like, so we knew what kind of dimensions and the sort we needed. We determined an idea, and we made a prototype. That which he had would ultimately be used for the actual stabilizer, though, problems were discovered (flimsiness primarily), so modification was necessary.
The third week consisted of continued work on the stabilizer. We decided to work with a model which we dubbed the "Twin Towers". With an obvious namesake for offensive purposes, the idea consisted of two main structures on opposite ends with poles in between to support the barrel. The idea was not apparently flimsy, but it was scratched for its overly complicated nature.
With the fourth week, we had a few ideas for the stabilizer which all held foundation in the original idea which we saw in the prototype. To be precise, it was all sort of like a wooden plank with two holes on opposite ends that would be used in a similar function to that of handcuffs. Except, instead of a man's wrists held within, it was the dual barrels of the cannon.
Here is a document on OnShape titled, "Aisha is gross". Chris Evans began and named this document (as if there was any question to its origins). This particular document is of our stabilizer. Two were printed out to connect the barrels. The two dibits on the top and the one on the bottom had sticks inserted in and subsequently allowed for the two copies of the stabilizer to be connected.
In the fifth week, we finally decided on a stabilizer which we would use. A snug fitting prototype was produced (we tested this on a cannon provided by Mr. Twilley), and we decided to print a final copy next time we had the chance. We also began messing around with some ideas for the base of the cannon.
All of October and a good ways into November was allocated for the express purpose of learning about and working with the Arduino.
Above is a video of one of our Arduino circuits which we created. Before watching here is a little bit of background:
The Arduino is a small, portable computer that was simplified so as to make the technology experience easier, more fun, and actually accessible to people who aren't necessarily the most technologically minded. The Arduino is capable of taking in many inputs and producing many outputs such as turning on/off a light or perhaps even playing a tune. As such, it is very capable of translating messages from the electronic world into actions in the real world. Above is a picture of the most common model, the Arduino Uno.
On the first week of non-Arduino work in November, we started and finished working in the workshop to produce the body of the cannon. We gathered the components, fitted them as necessary with the various tools available, and attached the pieces with the PVC primer and cement.
Sierra, using a miter saw, cuts the PVC pipe to an appropriate size for the barrel of the cannon. The pipes were originally too long and had to be made more suitable for the task. The miter saw is a good tool for the task as it contours to the object's shape and cuts quite smoothly.
A small hole was fashioned to glue a bike valve to the PVC barrel. We had to do this before we connected any of the pieces or it would have been very difficult. The valve will bring air into the cannon so as to add pressure.
The second week in after the Arduino process (which only consisted of one day), we wanted to print out the stabilizer, but we still found inadequacies in some of the measurements. We began some basic revision instead of actually printing.
The third week involved even more grueling assessment of the stabilizer. Not much more than that happened.
The fourth week finally yielded our final copy of the stabilizer which we were able to then attach to the barrels with only a little sanding involved. We were able to start really thinking about the base of the cannon and what we wanted. Determining the launch angle measurements were the primary focus of these endeavors.
During the planning period, we were still working out the best approach to achieving the launch angles which we desired. Here was a little bit of our jumbled thought process which probably made more sense at the time. Presumably, we were trying to find how far off the floor of the cannon's base that the trenches needed to be (that would hold the "sticks") so as to get the launch angles which we determined would work the best.
The fifth week was mostly brainstorming for the form of the base. We did ultimately determine that we wanted this sort of box complex that would have an open front and top face. Sticks, for lack of a better word, would fit into the side walls of the box and hold the cannon up. Measurements began to be drafted up.
The sixth and seventh weeks involved remeasurement of the original projections. We determined this based on a lack of stability and resources in our earlier design. A fair amount of math was also in this week as we found the lengths of the trenches in the sides of the box that would be necessary to place the sticks in so that our launch angles would be achieved. We did eventually reach an acceptable model.
Here is the digital model of the 4 major wooden parts which constitute the base of the cannon. In this media, they are ready to be printed into the physical world. These originally were produced through OnShape, but had to be moved here.
The pieces for the base of the cannon which we created via OnShape then had to be "printed" out. This tool, the shopbot, is hooked up to the computer and through this, it is able to read the digital models and produce our parts in the material world. However, this thing leaves behind quite a mess that forces one group member (me) to stay behind to vacuum up.
The eight week involved the process of the assembly of the base of the cannon. We got the pieces cut out (after a system malfunction of the shopbot on the first day), we sanded the pieces down as they were fairly rough, and then we assembled the pieces in the intended box form with a combination of a hammer, nails, and some good old fashioned elbow grease.
Using one of the smaller models of the table saw, Chris refines the dimensions and general smoothness of this wooden piece which will be used to prop up the front of the cannon. We had "printed" it out to precise measurements using the shop bot, but we found it didn't quite fit. When Chris finished here, the fit was much more snug and effective.
The ninth week was the last week of work. All that still needed to be done was the work on the rotation device which was achieved with cylindrical cookie container. Then, with everything together, we had the cannon.
Towards the end, we added rotational mobility to the cannon. To do so, we acquired a cylindrical cookie container which we thoroughly screwed with. The basic idea, however, was that this object would allow the main portion of the cannon to turn to face different directions without having to manually pick the whole thing up.
Above is the link to a video of the cannon actually launching a ball. Isaac attempts to catch the ball but unfortunately (for him) fails.
Some Problems Encountered Along the Way
- The "sticks" that supported the cannon were flimsy and one even broke.
- The stabilizer was easily found to be too flimsy and took a lot of time to produce to an acceptable degree. Even with the final copy, it had to be sanded down because it was a little too snug. The main problem with this was that a lot of time was wasted on this issue.
- We wanted to incorporate the arduino into the system, but we did not have enough time or understanding of the concepts to pull this off. We were not, if it wasn't obvious, good at allocating our time.
- We originally wanted to fire the cannon with the base facing upwards, but that always made the cannon fire too high. It actually worked better with the base on its side.
Below are some links to some of the more important documents that may or may not be referenced elsewhere in this portfolio; either way, they should be viewed.
Just so you can see, this is our cannon in all its glory.