#assignment_2

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Assignment 2: Mechanical Computer

How can people have an impact on the spaces which they inhabit? This is the question that I wanted to ask with this assignment. By creating a means of interaction with the people in the space, my project intends to essentially count the amount of people in a space, which could then be translated into a change in the environment. That change could be physical or ephemeral, or maybe even emotional. In this case, I wanted this change to be auditory.

Step 1: Switch and Relay

What do people do in a space and how can we use this as an input? I was working with the assumption that people will want to sit when they’re in this space, I think that’s a pretty safe bet, I know that I like to sit sometimes, The question then becomes, how do we record this input? The switch and relay that i designed would utilize the pressure created by the action of sitting, basically the seat would compress as a result of sitting, this compression would be translated via a plunger which would attach to a lever. When the input moves down the output will move up.

Step 2: Logic Gates

Now that we have an output, we need a way to combine a multitude of these outputs to produce specific results, this is where the gates come in. The first gate on the chopping block is the AND gate, a gate where and output is only created when both the inputs are 1. My and gate uses a similar system to the relay, utilizing a lever, this lever can rotate based on the inputs, but if both are 1 then the lever will move upwards on a track which would then create the desired result.

The next gate on deck is the OR gate, wherein an output of 1 is created if any or both of the inputs are 1. My OR gate uses a bar on tracks with inputs on both sides. As one input moves upward, the bar moves along with it, this works for either side and it will also function with both sides activated.

The final gate I designed was the XOR gate, where the output is 1 if any of the inputs are 1 but the output is 0 when both inputs are one. The XOR gate is an essential piece in a binary adder which is why I decided to design one, in hindsight this may have been a fruitless endeavor seeing that an adder isn't specifically necessary for what I was trying to see, nevertheless I designed one. The concept works as a combination of the two previous gates, the two inputs are attached to a bar with rotating joints, this means that one positive input would result in the bar rotating, but with two positive inputs the bar moves upward rather than rotating. This bar is designed to interact with another bar situated above it which controls the output, So by having the input bar rotate, the ends will start to push the output bar upward. The space between the bars is specified so that if the bar moves upward without rotation it will not interact with the output bar, instead stopping just below therefore not activating the output.

Step 3: Changing the Space

My intention with this project is to use the amount of people to effect a change in the auditory condition of the space The way I imagined this happening was that the inputs of people would interact with a wind organ by opening and closing valves to allow or prohibit air flow. In all honesty this ended up being rather weak and unresolved, the mechanisms I designed did not effectively interact with this system. If I were to move forward with this project I would definitely try and dive deeper into how these systems can interact and what they can interact with in order to achieve my goal.

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Assignment 2: Designing a Switch + Relay

I’ve set the goal of this piece as counting the people existing in a space. The intention being that the people would provide the input of the device simply by sitting or standing in the space. The device would then take these inputs into account and add them all together, which would subsequently produce a result specific to the amount. This result may have a visual representation or an auditory representation.

Switch

The fist step in the design process is to create the switch which will respond to the presence of a human. The switch I designed responds to pressure exerted by the weight of the person. A plate would that can either be sat upon or stood upon would be connected to a spring and plunger system which would move in the vertical direction. The system at rest would be in the up position, this would qualify as the 0, the system, when acted upon, would be in the down position, this would qualify as the 1.

Relay

The next step would be to incorporate the switch into a relay. The relay I designed would use a lever. The switch would provide the input to one side, while the other side would be connected to another plunger.  Each would incorporate a spring, which would allow it to move back to the rest position when the person stops providing the input. In simple terms, as one side goes down the other side goes up. When the output plunger goes up it could then interact with another lever which provides opportunity for compounding

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Mechanical Computing-Case Study

In doing research on the topic and application of mechanical computing I came across an interesting video. This video is a military training video from 1953, its purpose: to explain the systems that make a naval fire control mechanism work. Naval Fire Control meaning the system which controls the guns on board a battleship to accurately hit specified targets. The video starts with basics such as addition and multiplication by a constant, then moves into more complex and specific calculations taking into account speed, direction, line of sight, range rate, and bearing rate. I’ll include a link to the video in this post, then ill go into a bit more detail about the systems.

Shafts and Gears

The first system discussed is shafts and gears. This system is able to perform multiplications by a constant by varying the size of the gears in sequence. For example, a gear size ratio of 2 to 1 would result in one revolution of the driving shaft being converted to two revolutions of the output shaft, and so on and so forth. This is one of the most basic of mechanical functions.

Cams

The next system discussed is cams, cams convert rotary input to linear output, cams consist of two pieces, a working surface and a follower. The working surface is the rotary component while the follower is usually a pin that rests along the working surface and moves in response to the form of the surface. This means that by manipulating the form of the working surface one can generate multiple mathematical functions. A constant lead cam will function as a 1 to 1 representation of the rotary motion (used in this case for ship speed). A reciprocal cam will represent 1/input, a square cam represents the square of the input, and a tangent cam represents the tangent of the input. Cams can also function with two inputs and one output, this would be a barrel cam (in this case these produce super elevation which is a naval combat function and not necessarily relevant).

Differentials

The final of the more simple systems is the differential, this is a system of gears that can be used to generate the sum of specific quantities, an adding machine basically. In the simplest of terms, a differential consists of 3 gears, two act as inputs and one to act as the output. A simple diagram would be two linear racks to act as the inputs with a circular gear in between acting as the resultant out put. If assigned a measurement scale along each axis, one could start to see that by moving the two racks in specific numerals, the central gear would be situated at exactly half of the sum of the input numerals. From there, one could set the output scale to double that of the input which would result in the accurate sum of the inputs (if that is unclear, I’m including a visual diagram which will explain this better).

Component Solver

Here is where we start to look at the more complex and context specific systems at play in this case study. The first system would be the component solver, which is used to calculate and display 3 vectors: Ship Speed/Direction, Range Rate, and Bearing Rate. Basically, these 3 vectors make up a triangle which is integral to the aiming and targeting of naval guns. The system is a combination of multiple smaller systems. For speed and direction, the system uses a combined gear and cam, the ships direction relative to the line of sight to the target is plotted by a gear within which lies a slot which displays the direction. Integrated below this gear is a cam system which takes in the ship speed as an input and moves a pin within the slot on the gear, further to the end representing high speed and the center representing a zero speed. This pin then interacts with 2 perpendicular racks which represent range rate and bearing rate respectively. Since they are connected with the pin they will move along with it thus calculating and plotting the data.

Integrator

Another one of the context specific systems is the Integrator, its primary function was as a range keeper. By utilizing a rotating disc, two balls, and a roller, it was able to calculate the change in range from a target in real time. The disc would be representing the ships speed by rotating at a specific rate. The two balls would represent range rate through linear movement across the face of the disc. The movement of the balls would then move the roller which would calculate and display the range change. This range change could then be used to calculate the present range from the target. This system could be used to calculate both positive and negative range change as a result of the position of the balls, if they were on one half of then disc then the result would be positive, if they were on the other the result would be negative.

Conclusion

Through the combination and variation of simple systems, the amount of calculations possible is seemingly endless, provided that you have infinite time, space, creativity, and resources to achieve it. Although these systems are most definitely outdated, so much useful information can be gleaned through the observation of them in action. If nothing else, they certainly do provide some infinitely intriguing and mesmerizing visuals.

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The Good, The Bad & The Ugly: Assignment 2 Recap

Im going to start this blog by saying: YOU WILL FAIL! But with enough dedication, commitment and a ton of trial and error, YOU WILL SUCCEED and it will feel amazinggg!!!

Choose one LaserCutter and Stick to it!

Each machine will have its own tolerances, and it is unsafe to assume that testing results for one machine applies to the rest. The best recommendation for perfecting your craft is selecting one laser cutter and testing different material settings until you arrive at the best possible outcomes that result in the best possible fitting of pieces. I made the mistake of moving from one machine to another too many times which caused me to have to spend valuable time figuring out the best settings for that new machine instead of spending that time on improving the design.

Prototype early!

The absolute best advise anyone could ever give is to start testing models and gear ratios EARLY in the process (As early as the day you are handed the assignment). Our team went through three iterations of the design before we were able to arrive at a design that was elegant and (somewhat) functional.

Figure out your snap joints early!

Snap joints is what you are most likely to use to hold the car together. Because dealing with these kinds of connections is detrimental for the sturdiness and stability of your project, we recommend testing the snap joints simultaneously while testing laser cutter settings and material properties. 

Casting Rockite: Fly-Wheel Designs Only

Casting the flywheels out of Rockite was no easy task. The goal with the flywheel design is to get the most inertia possible with the least weight necessary. To achieve such desired outcome, I recommend casting the heavy rockite the furthest distance possible form the axis of rotation. Bulky material closer to the axis of rotation of the flywheel will add to the overall weight of the car without adding significant inertia i.e. energy storage to the system. All this extra weight will cause your car to move slower and for a shorter distance, as well as increase the friction between its moving parts.

Make it the lightest possible!

After arriving at a design that seems to functions, I recommend taking one last pass at the design but this time carving out any material that is not serving a purpose. You can achieve that by hollowing out parts of the chassis that exist between joints as long as it does not interfere with the structural integrity of the car. As mentioned before, Flywheels can be reduced in weight by adding material close to the circumference of the circle and away from the axis of rotation.

Make your Drive Axle hefty! 

This is something we realized after the fact; since speed in the flywheel is being transferred through the gears and transformed into torque in the drive axle, it is important for the drive axel to the consist of material that can tolerate such high torque. Because of that, it is recommended that you beef-up the drive axel in order to increase sturdiness and stability.

Final Remarks!

This assignment was a great challenge and an awesome learning experience all at the same time. In architecture, we are used to dealing with tolerances down to the 1/32″, which you may think is small but it is actually not. this Architectural-Engineering exercise made us think about functionality as a  variable depended on tolerances that went down to the 10th of a millimeter. This exercise was extremely eyeopening in that regard, and resulted in products we were all proud of.

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Assignment 2 Reflection

The self-propelling car assignment. 

Advice for any that are attempting this project.

The assignment is difficult and requires many hours of testing and a bunch of materials wasted. My project moved but only slightly, so my advice would be to focus on making the car as small and light as possible and have the majority of the car be allocated for the torsion spring, wind up coil, or flywheel. 

The gear ratio and torque will be stressed at the beginning of the project, but the main thing to focus on is the torque to weight ratio. The materials that are used are not very strong so cannot produce a great amount of torque, so the weight must be very low in order for your car to move. The gear ratio is important, but it may seem like a bigger one is better. The more important thing here is to get the gear ratio at a scale of your car, if the gear ratio is too high that is more for the car to push. 

I had a great time with this project and learn a large sum about gear mechanism and the design build process. 

Good Luck!

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The Moooving Mooog

A summary of the challenges faced and changes needed to be made in the final self propelling car.

Function

The car moved, but only as much as you pulled it back and if you were lucky it would move a little more off of inertia. The gear system design to propel the car forward at six times the imputed distance required too much of the one delrin barely function torsion spring. So as a result the car pushed itself through the pull back gear train at a one to one ratio with the torsion spring. This was not ideal, but enough to make the car move. 

Changes

There could be many changes to the car that would improve the function, all centered around the relationship from weight to torque. Our biggest problem was the torsion spring itself not being able to pull back without snapping and once it was able to not snap it did not wind up enough. A couple solutions to this are changing the size of the torsion spring, changing the number of torsion springs, changing the width of the torsion spring, or all of these things combined. These solutions all deal with the input, but another way to solve the problem is decreasing the amount of torque required to move the car. To solve that the car could become lighter through decreasing the amount of material used to construct the car, this could be done by slimming all of the layers of the car, decreasing the size of the car itself, or by taking out the layer gear assembly and moving to a stricter gear ratio making the car extremely slim. The last and simple solution would be to just take out the shifting gear mechanism and choose to have the car only rely on one gear train. This would make the car lighter, but also not require the torsion spring to move as many gears. I’m sure not all of these solutions would be as effective as I think they would be, but if a next car would be made it would be able to move a full two feet.

Design

The design change slightly over the course of the project, the main thing required of the body is to hold the axles in place. Apart from that requirement, there is much freedom in how the body can look. The final design was something that was simple and the intent was to show that it didn't need a fancy design to work. On the review, some comments include it was too design

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The third team’s toy vehicle is a tricycle that uses two flywheels made out of Rockite cement

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Demonstration of a functional toy car!