Soldering – Week of 03/09/2015

The Fifth Week

The primary goal of my SRP thus far has been to create a device that shows the applications origami can have to engineering. However, the secondary goal of my SRP was to explore the field of electrical engineering, and that is exactly what I did during my fifth week. With the help of the grad students in the lab I am working in (shout-out to Ian!), I learned how to solder and managed to solder a Planar Inverted–F (PIFA) antenna together. Here is a picture of the final antenna:

Here is a picture of the soldering iron and its holder:

When soldering, it is critical to “tin” the soldering iron with solder (a metal alloy) before placing the iron back into its holder. Iron can easily oxidize (also known as rusting) when exposed to air, and the extremely high temperature of the soldering iron only speeds up this process. By leaving some melted solder on the soldering iron before putting it back into its holder (“tinning”), the iron is protected from oxidizing. Unfortunately, someone who used the soldering iron before me forgot to do this, and now the soldering iron has a “dead” side. This meant that whenever I was trying to put some solder onto my antenna, I would have to rotate the soldering iron until I found the side that actually worked. Though this made the task more difficult, with some help I finally managed to make my antenna.

Though the way antennas work and what makes a PIFA antenna different is a bit beyond me, I was able to test the frequencies at which my antenna worked best using a network analyzer. With the help of Ian, one of the grad students in the lab I am working in, I was able to calibrate the network analyzer, connect my antenna to it, and then test the frequencies my antenna resonated at. Here is a picture of the network analyzer and the outputs I got:

According to the network analyzer, my antenna works best at 1.23GHz and 2.89GHz. That's all I have for now - until next time!

-Parthib Samadder

Writing and Research - Week of 03/02/2015

The Fourth Week

During my fourth week, I mainly worked on a report that detailed the variables and the application I was considering for my final product: my origami rover. In this blog post, I’ve included a few details from that report:

The Application

Rockets that take human-made devices to space such as the Space Shuttle or the Delta II rocket tend to have very limited space in their fuselage or payload fairing. Figure 3 shows how the fuselages of the Space Shuttle are either extremely small or has a very small width in comparison to its length. As a result, a collapsible rover would be extremely advantageous when fitting the device onto a rocket’s fuselage or payload fairing. When discussing rocketry, space (in terms of volume) is extremely valuable, and through using a rover that takes advantage of the Miura fold, a larger rover could be fitted into the fuselage/payload fairing.

Figure 3: A diagram of the Space Shuttle. Notice the size of the aft fuselage and the width of the mid fuselage.

Variables to Consider for the Folding Material

There are many variables to consider when choosing the material that will be folded into the Miura fold:

1. Ductility: The definition of high ductility is the ability for a material to change shape under tension without breaking. This is important to the Miura fold because many metals will break if folded and unfolded many times along a single crease due to its brittleness (low ductility). As a result, materials with low ductility is not ideal for this fold. In addition, folding metals seem to lower the ductility of that metal along that crease.
2. Malleability: Malleability is the general ability of a metal to change shape under compression. This property allows for a metal to be made into a sheet and be folded. However, a high malleability also seems to make a metal hold its folded form without change, which is not desired for the Miura fold. A Miura fold should be able to easily transition between its collapsed and decompressed states.
3. “Ability to hold a crease”: If a material is able to maintain a crease impressed on it, then origami could probably be applied to that material, and the material will probably have a memory of how it was folded. Robert Lang has used this idea to apply origami from materials ranging from cloths to metals.
4. Stiffness: Stiffness in this context is defined as “the measure of force required to bend a material through a specific angle.” If the stiffness of a material becomes too high, the advantages of folding the material into the Miura fold disappears due to the inability to alter the state of the Miura fold easily.
5. Curl: The curl of a material is defined as  “the systematic deviation of a sheet from a flat form.” One reason why a material may experience curl is due to internal stresses inside the material as a result of folding. This specific type of curl is called “Structural curl.” Ideally, the curl of the material should be low so that the stresses within the material does not cause the material to curl up when it is in the compressed state of the Miura fold.

Brief Discussion of the Size of the Rover

Rovers and space probes tend to be fairly large when dealing with space exploration in order to fit several instruments aboard the devices. For example, the Philae spacecraft for the Rosetta mission was nearly a cubic meter! However, rovers and space probes dedicated to a single instrument can be significantly smaller and have more power available to that single instrument. As a result, this project will focus on a rover smaller than the traditional rover.

That concludes my fourth week! I will try to catch up on posts by next week. Until then!

-Parthib Samadder

Further Reading

• http://www.materialconnexion.com/Home/Matter/MatterMagazine81/PastIssues/MATTER61/CreaseandFold/tabid/691/Default.aspx
• http://www.paperonweb.com/paperpro.htm
• http://history.nasa.gov/diagrams/e3-5.htm
• http://www.langorigami.com/paper/paper.php