Monday, January 12, 2015

A Homemade Horn

For awhile now, I've been fascinated by wind instruments, particularly the French horn. As mentioned in my previous post, I've always liked harmonics, and wind instruments rely on harmonics to operate, so naturally I wanted to learn to play. However, I had a problem: horns are expensive. So, I decided to make my own for about $10 at the hardware store.

I purchased 12' of .5" diameter tubing, a small copper pipe converter, and a set of funnels. These became the main tubing, mouthpiece, and bell of the horn, respectively. By simply sliding them into one another, I created a simple horn.


The interesting thing about this horn is that it's a natural horn: it can only play the overtone series, but no other notes. If the horn had valves to change the length of tubing, it could play notes outside of this series.
I have never played horn before, but I went ahead and made a video of me trying. Hopefully, I'll get better soon!


Wednesday, November 19, 2014

Playing an Octave in Just Harmonics

I've always loved the way that string harmonics sound. However, I've been unable to really do anything entirely with harmonics because you can't play a full octave using only harmonics. I decided to figure out how many strings I would need to play an octave and I came to the conclusion that three was the smallest number, and the three should be tuned in a first-fourth-fifth fashion. In my example, on the guitar, I tuned my top strings to E-A-B. This lets you play an E major scale, but 2 octaves up from the low string.


I decided to go ahead and try to play a song on these harmonics, so I settled on Minuet in G by Bach (although it is no longer in G because I had to transpose it to E).


I'm considering trying to figure out a tuning where I can do 2 octaves, and I think I may only need 5 strings, but I'm not sure.
It's also worth mentioning that this octave is in just tuning, a tuning system that makes the frequencies of notes in the octave whole number ratios times the tonic frequency.

Sunday, October 19, 2014

A Grand Day Out: Visiting the Mun in Kerbal Space Program.

Awhile ago, I decided to make my standard "Mun" rocket more efficient and more realistic. I was inspired by the original Saturn V rocket. I decided that rather than simply landing on the moon and going home, my lander would undock from an orbiting module, land on the moon, come back, redock, and fly home. This made the mission much more difficult, but much more efficient since I didn't have to bring the "going home" fuel down to the lunar surface with me.


The rocket begins with 5 large fuel tanks to achieve orbit. The fuel tanks use asparagus staging, making the rocket extremely efficient.


The craft achieves a low equatorial orbit around 70 km.


After achieving orbit, the craft uses the very efficient "Poodle" engine to extend its periapsis to the Mun's altitude.


The craft's orbit intersects the Mun's sphere of influence.


Once inside the Mun's sphere of influence, I make a retrograde burn at my periapsis to circularize my orbit. In the above photo, I am about halfway through the burn.


This photo shows the completed burn.


The lander (on the right in this photo) now detaches from the orbiting module. The orbiter first transfers fuel into the lander to help with the descent and ascent from the surface.


I performed a retrograde burn with the lander to begin the descent. Notice that the lander's orbit (blue) puts it on a landing trajectory whereas the orbiter's orbit (white) remains above the surface.


When the lander neared the surface, I performed another retrograde burn. Then, I set her down in the flattest spot I could find. I sent Handas Kerman out to plant a flag, and then it was time to go back home.


Contrary to achieving orbit back on Kerbin, on the moon, I perform a gravity turn almost instantly. Also, instead of just aiming straight east, I am aiming to intersect the orbit of the orbiting module.


Here, you can see the lander's orbit before the circularization burn. I managed to bring the lander and the orbiter very close on the first time around.


Here, the lander's orbit is almost exactly the same as the orbiter, allowing them to dock.


Here, you can see the orbiter (left) about to dock with the lander (right). The lander has its lights on, so you can see the orbiter in this picture. However, everything else is very dark because the Mun is blocking the sun.

After the two redocked, I performed a standard reentry maneuver to bring the craft back to Kerbin. Along the way, I jettisoned the orbiter module and only brought home the lander.




Recording Myself Playing Guitar

I decided to record myself playing guitar recently. My step dad scheduled a time for me to meet with his sound manager, and he agreed to help me. I recorded two songs, "Bouree in E Minor" by Bach and "Paranoid Android" by Radiohead. My guitar doesn't have classical, nylon strings, so "Bouree" doesn't sound so good because you can hear my fingers squeaking on the strings as I rapidly move around the neck. Other than that though, I was very satisfied with the end result of the recordings.

I don't have much else to say, so here's a link for you to download them and listen.

A Thing I Made Up: Kelly Diagrams

In my Vector Calculus class recently, we were tasked with writing a paper detailing all rhombic tilings of the sphere with at most two distinct "types" of vertices. A "rhombic tiling of the sphere" effectively means a polyhedron made out of rhombi. I found it difficult to visualize these polyhedra because they exist in three dimensions. Drawing them didn't help much since drawing is a 2D medium. However, I came up with a new way of diagramming polyhedra: the Kelly diagram.

The Kelly diagram for a cube.
To create a Kelly diagram for any polyhedron, draw all of its faces out flat. Then, draw loops around the corners of faces that meet at a vertex. This means that, in a Kelly diagram, each vertex is represented by a loop that encloses the corners of the polygons that meet at the vertex. For example, the Kelly diagram above represents a cube. Note that there are 12 loops, and each one encloses the corners of three squares (for the outermost loop, assume that the area around the drawing is the inside). This is because there are 12 vertices on a cube, and each one has 3 squares meeting at it.

Kelly diagrams were a very useful visualization tool in my paper. Using this new form of diagram, I was able to prove the non-existence of the rhombic octadecahedron. If you want to read my full paper, you can download it here. The file is an open document text (.odt) so you may have to download Openoffice to view it.

Sunday, September 7, 2014

Making a Jacob's Ladder Better

Around a year ago, my friend, Max Justicz, was graduating high school and headed off to MIT. As a parting gift, he gave me his 12000 volt neon sign transformer. It's been sitting in my closet since then, so I decided to finally put it to good use and make a Jacob's Ladder.


This was definitely cool, but it needed some improvement. Also a little over a year ago, my former robotics coach left our school to live in Connecticut with his wife. He let me keep his 12V air compressor, and for the longest time, I've been searching for a project to use it in. I realized that I could probably use the compressor to make the Jacob's Ladder spark upwards even faster by using the compressor to pump air along the wires in the direction of the arc's movement. This was the result:


As you can see, this was totally awesome. It ended up making something that looks almost like a plasma sword. This project was definitely worth the small amount of effort it took to create it. Overall, it's one of the coolest things I've built.

Thursday, September 4, 2014

Kerbal Space Program: Building a Low Orbit Fueling Station

For awhile, I wanted a way to practically apply my docking skills (that is, having one spacecraft attach to another in space). I used a little bit of the Infernal Robotics mod, but not much. I started off by sending up two base modules and docking them.

Two of these were attached at the front (the end with less docking ports)
After attaching the base modules, I sent up two large fuel tanks attached to one ship. I docked the first tank, then separated the second one, and then docked the second one.

Docking the first of the two orange tanks while the second is still attached. 

The completed station, with both fuel tanks docked. 
The station was complete. It had nearly full fuel tanks, solar panels for electricity, and six docking ports for refueling ships and future additions.