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==How to use== | ==How to use== | ||
Normal operation of the harmonograph is quite simple. Once | Normal operation of the harmonograph is quite simple. Once the pen and paper are secured to their respective pendulums, all you have to do is set the pendulums into motion by rocking them back and forth and drop the pen arm. To get different drawings from the machine there are a couple different parameters that you can change. First is the position of the weight. Moving the weight up and down will alter the frequency of the pendulum and therefore the harmonic ratio between the two. Next, the period can be altered by starting the pendulums at different positions in their swing. The final way to alter the drawing is to alter the amplitude of the pendulums. This can be achieved by putting more or less energy into the pendulum's swing. | ||
{{Gallery | {{Gallery | ||
Revision as of 00:30, 6 May 2013
Abstract
The Two Pendulum Harmonograph was created by Team C.R.A.M (Creative Reuse Art Machine) in the ENGR215 Introduction to Design class at Humboldt State Universityto fulfill the need of SCRAP Humboldt to have a an art machine made out of upcycled materials that they can take to schools and art festivals to demonstrate creative reuse. Other options were considered as a final solution to SCRAP Humboldt's problem, but the Two Pendulum Harmonograph was found to be teh best solution to the problem presented by SCRAP Humboldt. The project underwent many changes to become an art machine that visually demonstrates the interaction between two pendulum frequencies.
Background
Engr 215 Introduction to Design, a class offered by Humboldt State University, is an Engineering Design class. Every semester, the class designs specific products for a client to educate students and give them experience in working in group projects with clients. Spring semester, 2013, the design class worked with SCRAP Humboldt. Scrap Humboldt is a non-profit organization the aims to inspire creativity and sustainable behaviors for all ages, through creative reuse of materials from the waste stream.
Problem statement and criteria
Our mission was to create an art machine for SCRAP Humboldt to take to schools, festivals and other events to inspire creative reuse by being fun and interesting for people of all ages.
Specifications:
- Fits in a 1998 Volkswagen Beetle.
- Made out of 75% or more reused material.
- Able to be carried by 1-2 people.
Considerations:
- Will be used by adults and children.
- Needs to be easy to setup and transport.
- Must complement SCRAP Humboldt's existing paint spinner.
Criteria is weighted 1 to 10, 10 being the highest.
| Project Criteria | Description | Importance (1 to 10) |
|---|---|---|
| Safety | Safe for both adults and children | 10 |
| Engaging | Visually stimulating | 9 |
| Repairability | Easy to repair | 8 |
| Durability | Ability to withstand daily use by both adults and children | 7 |
| Unique Design | Ability to create more than 2 different unique designs | 7 |
| Ease of Use | Easy to use | 6 |
| Portability | Ability to fit in a 1998 Volkswagen Beetle and can be carried by 1 or 2 people | 5 |
| Cost | Cost less than $300 | 4 |
Description of final project
Based on our criteria, we decided that a two pendulum harmonograph was the ideal solution. A harmonograph is a machine that uses pendulums to create parabolic curves, or Lissajous figures. As pendulums swing, they swing at fixed frequencies. The pen and paper track the combination of the two frequencies and create a drawing. The drawings show the harmony between the two pendulums. Shown below is a diagram of the final solution with labeled parts.
Costs
Materials cost with retail price and actual project cost.
| Material | Use | Quantity | Retail Cost ($) | Retail Cost Total ($) | Project Cost ($) |
|---|---|---|---|---|---|
| 48" x 1/4" x 1 1/2" Wood | Pendulum Arms | 4 | 2.50 | 10.00 | 0.00 |
| Table | Force of Gravity Neutralizer | 1 | 25.00 | 25.00 | 0.00 |
| Brackets | Gimbal Brackets | 4 | 0.75 | 3.00 | 0.00 |
| 4" x 1/2" x 2 1/2" Wood | Gimbal Blocks | 4 | 0.50 | 2.00 | 0.00 |
| Bricks | Pendulum Weight | 4 | 0.50 | 2.00 | 2.00 |
| 3 1/2" Bolts | Secures Writing Instruments | 2 | 0.59 | 1.77 | 1.77 |
| 6" Bolts | Secure Weights | 6 | 0.79 | 4.74 | 4.74 |
| Wing Nuts | Secure Weights | 6 | 0.30 | 1.80 | 1.80 |
| Bolt Nuts | Secure Weights | 10 | 0.10 | 1.00 | 1.00 |
| 1 1/2" Bolts | Fulcrum Pen Arm | 2 | 0.94 | 1.88 | 1.88 |
| 3 1/2" Bolts | Gimbal | 4 | 0.86 | 3.44 | 3.44 |
| Wood Screws | Reinforcement | 16 | 0.03 | 0.48 | 0.48 |
| Plywood Board | Writing Surface | 2 | 7.50 | 15.00 | 0.00 |
| Binder | Writing Surface | 1 | 7.00 | 7.00 | 0.00 |
| Total Cost | $79.11 | $17.11 | |||
Maintenance cost
In order to ensure proper use of the machine, minor maintenance will need to be up kept. First, the pen must be replaced when the ink runs out. Next, every time the machine is set up, use lubricant on the joints where the pen arm connects to the pendulum.
The machine is comprised mainly of wood products and must be stored in a dry area to mitigate mold and warping within the parts. Finally, the surface underneath the paper may become rough from use, so it may need replacement if this occurs, though this is unlikely.
| Maintenance Task | Frequency | Cost/Year ($) |
|---|---|---|
| Replace Pen | When Ink Dries | 0.00 |
| Replace Paper | After Every Drawing | 0.00 |
| Lubricant | Before Each Use | 5.00 |
| Total Cost | $5.00 | |
Testing Results
Through testing, we found that the harmonograph needed low friction between the writing utensil and the writing surface. Therefore, we found gel pens and printing paper work the best.
- Final Product
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- Harmonograph results
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How to assemble
The first step in using the harmonograph is to assemble the machine. Start by unfolding the card table and putting it on a flat stable surface. The next step is to take the pendulums and insert them through the slots in the table. The pen arm pendulum goes in the slot that orients the pen right above the other slot. This other slot is for the paper platform. If you put the pendulums in the wrong slots the pen arm will be pointed the wrong direction.
To insure the gimbal is properly aligned, the pointed bolts must go into the depression on the gimbal stand which keeps the pendulums from shifting around.
The final step is to attach the weights to the pendulums. The paper platform weight clamps down on the pendulum with two bolts cinched together by wing nuts. This clamping mechanism allows for quick weight height adjustments. The pen arm weight has a long bolt that must be fed through a hole in the pendulum. This weight is not meant to be adjusted.
How to use
Normal operation of the harmonograph is quite simple. Once the pen and paper are secured to their respective pendulums, all you have to do is set the pendulums into motion by rocking them back and forth and drop the pen arm. To get different drawings from the machine there are a couple different parameters that you can change. First is the position of the weight. Moving the weight up and down will alter the frequency of the pendulum and therefore the harmonic ratio between the two. Next, the period can be altered by starting the pendulums at different positions in their swing. The final way to alter the drawing is to alter the amplitude of the pendulums. This can be achieved by putting more or less energy into the pendulum's swing.
Discussion and next steps
Weight adjustments
- Easier way to adjust weights
Larger dimples for gimbals
- Smaller dimples leads to gimbals slipping out
Improved pen arm design
- Less friction
- Less pen arm play