Week 9 Outside Meeting #2 - Machine shop

Finally! Success! At the machine shop we used epoxy glue to make the K'Nex base MUCH sturdier. That had to set for an hour. After that, we aligned the system, put tape on the wheel frame and wooden block to remember how to set it, and then mounted the K'Nex base with zip ties. 
Here is a picture of the glue on the base: 

Week 9 Recap

Mechanical

During class today we scratched the tape/wheel idea and just sanded down one of the edges so that the belt would fit the wheel without any extra components. That worked really well actually! 

Jacque using the power tool to sand down the inside edge of the wheel

We also used a heat gun to morph the ends of the belt together. Here is the result!

Now we just have to go back to the machine shop to mount the base again (for proper tension) and to align the whole system properly. 

Electrical

Datasheets:

• http://www.instructables.com/id/Wire-a-Potentiometer-as-a-Variable-Resistor/
• https://www.sparkfun.com/datasheets/Components/LM7805.pdf
• http://www.fairchildsemi.com/ds/LM/LM2901.pdf
• http://www.bourns.com/pdfs/3006.pdf

Week 9 Outside Meeting

Mechanical Group:

Today we went to the machine shop and made some serious progress. Along with the help from the machine shop crew, we built a base for the wheel to sit in made of a wooden block donated by the shop, mounted the k'NEX base by drilling holes and holding it with zip ties, and attached the lego piece to the generator shaft by using a mold and screw. 

Here are some pictures of our progress:

The base mounted with zip ties

Close up of the base mounted with zip ties

Sarah posing with the tool used to drill the hole for the bike base

View of the whole thing!

In-Class To Do:

• Glue in wheel
• Attach generator to base
• Set up belt

Electrical Group:

In-Class To Do:

• Set up the breadboard with wires and all the pieces
• Continue needed calculations
• Solder etc.
• Draw up how to attach the electronics and LEDs

Together:

Need to work on the presentation and the final paper (due next week)

The presentation will be in LeBow 240 in the Hill Conference Room

Final Paper:

• Correct the errors and tweak until up to date (Jacque)
• Circuitry update (Courtney & Jess)
• Research corrections (Courtney)

Presentation:

• 10 minute speech with 2 minute question-answer session
• Upload slides to include:

• Title Slide (Sarah)
• Presentation Outline (2nd slide) (Sarah)
• Paper in slide form (All of us with)
• Introduction (Sarah)
• Project Objective (Sarah)
• Project goals and timelines (Sarah)
• Project budget (Sarah)
• Preexisting waterwheel and surrounding exhibit (Sarah)
• Research (Courtney)
• Overall design (Jacque)
• Calculations (Jacque)
• Mechanical & Electrical design (Courtney & Jess)
• Results (Megan)
• Future work (Megan)
• Question Slide (Sarah)
• References Slide (Courtney)

We set up a GooglePowerPoint so we each can contribute to the presentation and make modifications without having to convert from Mac to PC.

Week 8 Recap

Mechanical Group: Jacque, Sarah, and Megan 

 

To have the belt fit perfectly on the wheel and not slip off, we covered the wheel in duct tape and then layered more tape on the sides where the edges of the belt would end. This worked very well! 

Next, we modified the base structure to be very sturdy and to have a place to put the generator. In these photos, the generator is not yet fully mounted, but will be soon with zip ties. 

Front view of base (facing the wheel head on)

Side view of base

Top view of base

View of the generator shaft and the lego piece it needs to fit

NEED TO DO: 

Visit machine shop next week and ask about suggestions on how to fit the generator shaft into the lego piece and how to mount the wheel and base to the wooden board. 


__________________________________________________



Electronics Group: Jess and Courtney 


Want LEDs to run in a parallel circuit (so that each bulb lights up at different times)

Going to first try using a current with 4 milliamps

The lights require 3 Volt batteries (9 Volts will kill the LEDs)

FROM EXPERIMENTING:
the light from the LED is discernible when it reaches 2.4 Volts and needs 4 milliamps

When the wires are connected and attached to the external power source, the total amperage reaches 12 milliamps. 


NEED TO DO:

calculate the resistor we need to get from 5Volts emitted by Voltage Regulator
(using 5 mA, 3V bulb, +/- 2V resistor)

need to look up datasheets for the 7805 

Week 8 Outside Meeting

An hour before class, we took a look at the current K'nex structure and how it fitted with the generator we ordered. We also got the wooden base for the overall prototype.

Current K'nex base as of 3:30 pm May 22, 2014

Goal for what our prototype will look like

The LED blue lights also came in yesterday (see picture). They are about 5 millimeters in size with 14-inch long wires (DC). We bought five of them just in case, but we will only really need three.

We managed to retrieve an axle from LeBow 132 that we need in the K'nex structure (as seen in the close up picture of the base).

The plan for today during class is to split up into mechanics and electronics:

• Mechanics: 
• Figure out how to mount the generator to the existing K'nex base
• Fit the axle to the base
• Mount the K'nex base to the wood
• Electronics:
• work on the LEDs and electronic portion of the project

Week 7 Recap

In class today, we addressed the to do list we created from last time:

• Choosing a set of materials for the other wheel

So we are going to use a Lego wheel - one with a radius of about 0.75 inches (0.56 inches really).

• Get reflector off of bike wheel

Took a while, but we managed.

• Design support base for smaller wheel

The support base is made out of basic K'nex pieces.

 

Top left & right: the first version of the base structure for the small Lego wheel.

Bottom left: the team working hard on building the support.





The generator has to be mounted within the vertical plane relative to the suspended Lego wheel. 
But because we do not have the generators on site with us, creating the base from the mix of Lego and K'nex pieces was impeded. The generator is about 30 mm in diameter, 48 mm (~1.75 inches) long, and with a shaft of 2.5 mm. 

Generator image from Ebay

• Base structure

Megan and Sarah are going to go get some wood so we can construct a wooden base to hold the bike wheel and fork as well as the K'nex wheel

• Lengths and distances for belt system

Some pictures of the small wheel with the urethane belt we received:

Top left: the bike wheel that we received from Wolf Cycles with the urethane belt.

Top right: the small Lego wheel with the urethane belt and bike wheel.

Bottom left: close-up of the Lego wheel and the urethane belt.

Thanks again to Wolf Cycles for the bike and fork!

Next:
we need to get a shaft from LeBow 132 Engineering building

Week 7 Outside Meeting

So we are still consulting with our TA, Marco. From his suggestions, our next in-class meeting will concentrate on:

• Choosing a set of materials for the other wheels (right now we are thinking of using a K'nex wheel)
• Get the reflector off of the bike wheel
• Design support for smaller wheel
• Need base structure: co-linear, vertical, and constant
• Figure out lengths and distances for the belt system

By meeting of Week 9: the generators should be here, so then we can set them up and get the wiring and circuitry done


FINAL REPORT:
Researching Section: Courtney
Calculations Section: Jacque
Mechanical Work: Sarah and Megan
Abstract: Jess (everyone helps edit for continuity)

Email draft to Marco: Jacque


Researching LEDs:
(http://www.modeltrainsoftware.com/miniatureleds.html)

This site sells 3V blue LEDs (technically for miniature train sets, but this suits our needs). Luckily they mention on site that the parts ship next business day and cost $2.25 each.

Week 6 Recap

Today we had to look at the big picture and make some BIG changes to our plans. 

We aren't doing a full-scale Please Touch Museum exhibit for the water wheel. Instead, we are doing a full-scale prototype model of the system of belts and pulleys that would be attached to the water wheel at the museum.

So it's week 6 and the deadline to have a physical representation of what we've been up to is a whole lot closer this side of week 5. We walked all the way down to Wolf Cycle to get bike parts. We got a 24 inch wheel -- that's actually a 19 inch rim when not counting the tire (see picture below)  and a fork to fit it. 

This bike wheel part (minus the tire) will be the giant wheel from that diagram Jacque drew in week 5's recap. Next we have to calculate out the proportions so all the other wheels will be proportional to our big 19 inch bike wheel.

We also need to order the belts and wait for the motors to get here.

Week 6 Outside Meeting: Researching Materials

Flat Belts

(the following information was from: http://www.gatesmectrol.com/common/downloads/files/mectrol/brochure/GatesMectrol_Belt_Pulley_Catalog_5_11.pdf )

Features:
Smooth, vibration free operation
Use with small pulley diameters
High strength, low stretch for long life
Sealed edges, no cord fraying
Easily guided with flanged pulleys
Kevlar or steel cord construction
No lubrication needed
No retensioning required

Application Characteristics:
Heavy load lifting or lowering
Allows for "slip" requirement
Smooth uniform motion
Small bending radius for small design envelope
Very low stretch characteristics

As seen from the photos, the best part about flat belts is how it can be used on a smaller scale, the make of a flat belt purposefully reduces stretching and wearing out, and can be used with pulleys with smaller diameters. The charts are helpful when we need to determine the coefficients of friction and weight etcetera when we need to decide what the flat belt's material should be.

Also, for future reference, we can use the following site:

http://gatesmectrol.com/mectrol/brochure.cfm?brochure=5256&location_id=6150#TOPOFPAGE : this chart (materials for belts)

Pulleys

Needs to be:

1. groove to keep pulley in place

2. waterproof (either waterproofed easily or already)

3. rigidity

4. machine-ability

5. light-weight

6. low maintenance

7. able to keep belt on the track with minimal outside help

http://engapps.gates.com/LinearApp/MotionCalculator/Step1 : helps to determine which belts, pulleys, and what materials would be needed based on certain input parameters

https://woodgears.ca/bandsaw/crowned_pulleys.html :

Gives a short history of how crowned pulleys were used with flat belts in addition to more information of flat belts and crowned pulley applications. 

While nowadays we use V-belts, the older technology used flat belts in combination with crowned pulleys. A crowned pulley is a pulley that has a slight hump in the middle and tapers off slightly toward either edge (as shown in the photo below).

This tapering edge helps to keep the belt on track automatically. In order to better illustrate this concept of the pulley helping the belt to stay on track, the author demonstrates with a rubber band:

"The key to understanding the flat belt tracking on a crowned pulley is to look at how a belt flexes when pulled more on one edge than another. I'm pulling the rubber band in the photo on just the right edge. With more tension on the right side, that side stretches more, and the rubber band forms a slight arch. In an actual belt, this stretch is too subtle to be seen by just looking at it.

"To better demonstrate the principle, [the author] built a jig from Lego, using a rubber band and an exaggerated crowned wooden pulley. The higher section of the crowned pulley puts more tension on the rubber band than the narrower edges. As a result, the rubber band flexes into a slight arch towards the middle. As the rubber band winds onto the pulley, this arch causes the band to always wind further up on the conical section than what was previously wound on. The higher point on the pulley always creates more tension in the belt and causes it to arch in that direction.

"With this exaggerated crowned pulley, it takes just a few turns for the rubber band to wander from the edge all the way to up the center hump. Once the rubber band is on top, the maximum tension will be in the middle of it, and it no longer has any reason to arch in either direction...With much more subtle crowning on a typical pulley, the self-centering of the belt happens more slowly." 

The following information was quoted from http://www.niba.org/index.php/resources/technical-articles/0603-crowned-pulleys/

"In order to be effective, a crowned pulley requires that the conveyor system have enough tension in it to force the belt to conform to the configuration of the pulley. Experience has also shown that a crown is most effective when it has a long unsupported span of belt approaching the pulley (3 feet plus, with little added effect over 10 feet) That is, the belt must be free of the effects of troughing idlers, rollers, slider beds, etc., for the crown to offer significant tracking advantages.

"...A crowned pulley should never be run against the coated conveying side of a lightweight belt.

"...Belts with high transverse rigidity require less slope to the face of the pulley to allow the belt to conform to the crown and influence the tracking of the belt."

 Essentially, a crowned pulley needs a lot of tension from the belt in order to actually keep the belt tracked. 
So we next had to research how to calculate the tension of the flat belt we would need.

We will be using the calculator program from http://www.niba.org/resources/belt-tension-calculator/. The math behind this calculator is clearly explained on their website.

From the site http://www.visusa.com/belt_tracking01.htm, we looked up the typical crown radius specifications when used specifically with flat belt pulleys.

Week 6 in class plan: 
1. Group: Continue discussing materials, ask for teacher opinions 
2. Courtney and Jess: discussing electronics, what we need to build or buy, how we're going to do that
3. Sarah and Megan: purchase materials for pulley and belt 
4. Jacque: design and plan to purchase materials for raindrops 

5. Group: Think about prototyping possibilities 

Meeting with Marco / Week 5 Recap

On April 30th, I (Jacque) met with Marco (one of our advisors) to go over calculations and possibilities for generating the voltage with the available rpm the water wheel gives us without any external pumping. We have about 6 rpm to work with and a radius of 0.5 meters. We also figured in order to power one yellow or red LED we'll need at least 3 volts (the least amount required for the available colors).

One generator that we found requires 900 rpm to generate 3 volts. This can be seen here on ebay.

Using the relationship: 

ωA represents the angular velocity (rpms) for the water wheel and rA represents its radius. ωB is the angular velocity we'd get with water rB we decide to use. At first this was upsetting, figuring that for 900 rpm we'd need a final radius of 3 mm. Wowza! That seemed not very feasible, especially for the durability we're looking for, so we had to consider our options. An amplifier? That would require external power, not ideal, but it could work. Maybe use a bike dynamo? That may require too much torque/inertia, which we do not have much of. We met before class to discuss, but didn't come to any serious conclusions. 

During class, however, Dr. Scoles had the idea to do more than 1 wheel ratio. Brilliant! This means that we'd hook up the larger pulley that is attached to the water wheel to a smaller radius with a belt, and attach a larger radius to that smaller radius, so from there we could have another belt to an even smaller radius, getting an actual decent amount of rpm! Here's a sketch of what I'm trying to say: 

And with the ratios in this spread sheet, we can reach at least 900 rpm:

These ratios seem a little crazy, but we think it is definitely doable. It'll have to be! This coming week we're going to search for DC generators like the one on ebay (only issue with that one is it takes 2-3 weeks shipping! But if we have to order it from there, we will). We also have to consider materials to make the pulleys and what belts to buy. 

Other in class accomplishments: 

Jess & Courtney:

They had to calculate the mass of the existing water wheel to continue the "Background" section of the blog. We obviously needed to estimate every measurement, and most of these estimates had to come from looking closely at the photos we took from the Please Touch Museum. 

Courtney & Megan: 

They learned how the external power source operated along with a small example moter complete with working gears encased in clear plastic. The max voltage for that particular motor was 3 volts, but had been known to make it safely to 5 volts for no more than 10 seconds. Hopefully we can use this generator/motor or a similar one for our project. 

Sarah: 

She worked on the final project. 

Week 5 Outside Meeting

On April 29th, We met up to further discuss the design of the mechanical and electrical systems. The main decision to  be made was whether we were going to use belts or gears for the system. 

First we had to research the basics of gears and belts, putting together a simple pros-and-cons chart:

Most of the research comprised simple Google searches, including more in-depth looks at the following links:

http://wiki.answers.com/Q/State_the_advantages_and_disadvantages_of_gears_system_and_belt system?#slide=1

This site provided us with a quick slide show that detailed several advantages and disadvantages of both gears and belts used within mechanical system. 

http://www.newworldencyclopedia.org/entry/Belt_(mechanical)

This site, from a scholarly source, described the different types of belts, their usefulness, and their common shortcomings. Most of the pros and cons for belts came from this site.

http://en.wikipedia.org/wiki/Belt_(mechanical)#Flat_belts

Once we decided we wanted to use a flat belt, we wanted to research more about flat belts in particular. This site was helpful in determining the specific shortcomings and advantages of these types of belts.

http://www.amazon.com/s/ref=nb_sb_noss_1?url=node%3D16412081&field-keywords=gears+plastic&rh=n%3A16310091%2Cn%3A16310181%2Cn%3A16412081%2Ck%3Agears+plastic

For a feasible comparison, we went on amazon to find some listings for gears to see what the price range would be.

http://www.flatdrivebelts-anysize.com/Belt-Pricing.html

For the same reason as the gears, we looked up some price ranges for flat belts (we also looked on amazon).

After a lot of deliberation and a vote, we decided to proceed with our design using flat belts. On amazon we found a feasible option for our purchase that works with our budget.

This is another video that is also very helpful in visualizing the parts we're going to need to put together. 

Week 4 Recap

Research:
We received a series of leading questions from Professor Scoles in order to help further the research portion of our project. To address these questions, we decided to create a new tab titled "Background".

Design:
Today in class we looked at the pictures and videos of the water wheel in the museum and wanted to decide on a design for the project. First we drew the wheel on the board from several different angles. 

   

Then we discussed where we could put the generator, lights, and rotation device as seen in the following image. 

Next we had a discussion on gears and belts. Gears would be easier to maintain, but belts would be more feasible in the time we have left this term. Our team plans to research both options and have a decision by next week's class as to which system we would use in our design. The below is a rough sketch of the gear system on the left an the belt system on the right. The gears would have a large gear with many teeth that turns the smaller gear to turn faster. 

Here's a video of a homemade water wheel! It is definitely pretty far from what we are going to be able to make, but the general idea of hooking it up to a generator and then to a light is the same. Now we have to figure out how to make the axle rotate along with the rest of the wheel! 

Week 3 Recap

Week three was really when we started picking up speed in terms of the project. We decided to really focus on the waterwheel idea since the Rain Forest exhibit already had a working waterwheel that we could build off of. The Rain Forest exhibit has a earthy theme to it: there are clouds, a glowing sun, light-up rainbows, and tons of water-related activities for the children. 
The water wheel can  actually be controlled by the kids. While the wheel always turns due to the perpetual flow of water coming from one of the tubes, the kids can push down on a button connected to the waterwheel to make more water come out the other tube and makes the wheel go faster. While at the museum, we had to think about how we would make our idea worth while for the kids. We need to consider repetitive action, manual control, and an exciting end result. We are planning to place some LED lights above the wheel that will have their energy generated by the rotation of the wheel (a demonstration of hydraulic energy). Repetitive action will be encouraged because the lights will turn off and the kids will have to do the activity again to keep the lights running. The more the children push the button, the more water will be poured onto the wheel, and thus the more energy will be generated to light up more lights, an exciting end result. The kids will control the amount of water that comes out through the pushing of the button, an example of manual control. As seen in the picture, the water wheel is a good size, but the kids can't reach the wheel from the sides which will work as a safety precaution. We have many creative ideas regarding the lights that will hang near the wheel. For example, the lights can be like lightening bolts, rain drops, or even just normal bulbs, but the project needs to fit in with the theme of the room. Below is a video of the  Please Touch Museum's waterwheel spinning with the perpetual stream of water (without pushing the button).

This is a photo of the Please Touch Museum! The group went with our advisor, and we explored all of the exhibits and got to know the ins and outs of the museum as we were assisted by Claudia, an employee of the museum. There were many great opportunities, but one that stuck out the most was the river in the middle of the Rainforest Rhythm exhibit. We want to try working with that, somehow modifying the existing water wheel into a source of power for a generator and then to light bulbs (possibly shaped like raindrops!). There is a lot to learn and research, but at least it is a start!

There seemed to be many outside opportunities, and we discussed the sustainable playhouse as well as the solar powered figurines, but we might be better off just focusing on the wheel for now. The museum would need a hefty grant for the playhouse, but maybe if time permits we can start a draft for an idea. But first, we have to figure out how to hook up a generator to the water wheel! 

Weeks 1 - 2 Recap

Weeks 1 and 2 have been productive in the brainstorming area, but we're still really waiting to visit the Please Touch Museum to make any final calls. Thankfully, that will happen tomorrow, so there will be more to discuss then! So far, we know that the museum wants us to revamp their old exhibits and give them a unique STEAM (science technology engineering arts and mathematics) approach. We are currently not exactly sure what we have to work with, but we know we must appeal to younger kids as well as teach with clarity, excitement, and simplicity. 

For now, here are some ideas we have come up with: 

1. Solar Energy - solar powered dancing figurines, solar powered race track - kids can find inspiration to dance along with the toys, or they can pretend to be a race car driver as they watch the cars move down the track 
2. Wind Energy - pinwheels powering lights, a large model wind turbine - kids can blow on the pinwheels creating energy to shine beautiful lights 
3. Water Energy* - waterwheel powering a model town, music, or light - kids can run water through the waterwheel to watch a town light up or dance to music being powered 
4. Sustainable Playhouse - there are a lot of ideas to go with here, but many seem pretty unattainable. We could have a green roof, bio wall, solar panels, or even decorative but relevant items like sun catchers or wind chimes - kids could play house and get a glimpse of what it would be like to have a home that is fully sustainable 
5. Mechanical Energy - cranking a wheel or running on a belt to power something - kids getting active and transforming their own kinetic energy into electricity 

*The water energy idea seems most relevant now after hearing what the museum has to offer. They already have a waterwheel, so maybe we could do something with that, or build around it. 

All of these ideas seem to have a lot of potential, but it all rides on how the museum feels about their attainability, relevance, and safety. We will have plenty of more ideas come tomorrow, quite possibly having nothing to do with what we have come up with currently, but at least it's a start to something that is going to be great and original!