Lynn's Blog

The designing and creating process of this whole project was really rewarding. To make my toy, I followed the cycle of defining our device’s criteria, developing a plan to create the device, then actually constructing the toy. The goals I set for my toy revolved around my client’s (children) needs as well as the requirement that this toy needs to show energy conversion. These goals included: making sure that my product considered environmental impact, is safe (durable) for kids, and also that the final device is functioning and eye-pleasing.

In the end, my final product almost met all criteria that I set for it. First of all, I guaranteed that my toy was durable and safe by making the device container more thick and heavy with layered hard cardboard (instead of the softer kinds of cardboard). Secondly, my final product considered environmental impact because it was constructed from recycled material and it also uses a renewable energy source to power it. Third of all, my design was aesthetically pleasing since all the components of my toy were cut from precise measurements (for example, the angle of the cardboard that has the solar panels attached to it). But, the only criteria I didn’t meet was making sure that my device functioned. If it had worked, the process of energy conversion would’ve been more obvious in my product.

The problem with my device was that the handle used to move the pulley system would not spin as I tested. This was due to the fact that the electric DC motor used to spin the handle did not have enough strength. I ended up coming up with the solution, after observations and feedback from users of adding another solar panel into the series circuit of the other two solar panels, by putting it on a cardboard extension of the device’s container; this would’ve provided an increased amount of voltage for the motor and make its rod spin stronger.

This was a challenge I faced for my project, but however, because I did not have enough time to do this, I ended my project at its first prototype. Before, I thought that if I maybe refined the other components of my project to make them burden the motor less, the motor would work. I used a lighter string and smoother materials for my pulley system, and I also reduced the distance between the pulley and motor, yet through testing, my toy still did not work. You can see it in another video right here: Movie on 1-18-19 at 3.26 PM (one of the vertical boards was blocking the bolt nut’s movement, but basically it did not move. It only moved as intended in an up or down movement when I used my hand to forcefully turn the handle, I hope that you can see that through the motion of the pulley wheel instead).

Another thing I possibly could’ve improved on was maybe adding some soft materials (clay or foam) to the hard edges of many places in my device. Since this was made for children, I want it to be safer for them to experiment with. I could also wrap the vertical boards in plastic wrap for the kids so they can avoid painful splinters.

Additionally, I also compared my final device with the initial concepts I had for it at the start of this project. I actually used multiple components of the different other devices I found online; for instance, the reason why I wanted to use renewable energy to power motion and electricity was from the wind turbine energy generator and solar energy car I found from YouTube. I got the inspiration of generating sound energy for my device from another video, and I also incorporated the pulley system idea as well. Most of the research I did at the start of the project all made its way into my final toy somehow.

To finish up, even though my product did not function, I still felt like this was a very educating experience. I actually learned how to use a variety of tools to engineer a project, and how to design things to tailor needs for a client. It was very involving and interesting!

Throughout the process of creating my project, which is a pulley-system sound generator, I was able to learn many things through trial and error. My project wishes to show the energy conversion process of light energy then to sound energy. It displays this through a device meant to educate children that is complete with a pulley system, solar panels, electric motor, and drum.

Along the way, I had to consider many things while creating my work, such as: “Would this be suitable for my customer (as in usefulness, durability, attractiveness)? Would this work? How can I make this show energy conversion more clearly?”. By asking these questions, I realized many slight errors in my sketch, and changed a few things. I also created several prototypes for each section of my project and assembled them together in the end using tape at first, then hot glue. Other than making prototypes and refining them, I also tested using established criteria, and optimized my design from feedback of users.

Shell and device container:

On the first day for creating this project, I first started working on the shell of my pulley-system sound generator; it was made of double-layered cardboard strips glued together to stabilize the device as the motor rotates. Since one of the criteria that I first identified at the beginning of this project was to have a durable toy for children, I wanted to make sure that the shell containing everything was durable and steady.

My main goal while building was to make sure everything was most suitable for my solar panels as well as my electric motor (as the shell contains them), so that the energy conversion process is more apparent in this device. As I worked on the board that the solar panels would be attached to, I realized, however, that the electrical wires of the panels would not be able to connect the boards and the motor since the cardboard had no hole in it. I ended up cutting two circles, each with a diameter of 2.5 centimeters, off the cardboard.

I also realized that the angle of the solar-panel-attached cardboard (40 degrees) was too small to receive the most amount of sunlight. This would weaken how observable the conversion process is, so I ended up changing the angle to 55 degrees after I did some research for my calculations (it turns out that the optimum tilt for a solar panel is its location’s latitude; it also depends on season, so if it’s in the winter, another 15 degrees should be added. This is why my solar panel angle is 55 degrees, since Beijing’s latitude is around 40 degrees).

(The little triangles, as shown in the picture above, are to make sure that the cardboard is 55 degrees. I changed their degree after the first prototype)

Electric motor and solar panel system:

I worked on the complicated system of the solar panels and the motor for the next few days. This one took a lot of time and revisions to complete because we had to figure out how to make sure that the electric motor receives enough energy to rotate. I started with my first prototype: with one solar panel to test out how the motor fits best with the solar panel, and how well the motor would work with a handle attached to it while only wired to one solar panel.

One of the first challenges I ran into was which type of DC motor would fit the electric panel best. I ended up with a small-sized DC motor after testing several motors one by one with my single solar panel. Under direct sunlight, the motor rotated well and successfully.

Here is a video of it (press link): singlesolarpanel

However, even though the handle seemed to work well, it would occasionally become “stuck” on the rotating rod of the electric generator and stop spinning. My conclusion was that the electricity produced by one solar panel was not enough to power the motor to rotate the rod. This means my model sketch was right, and I would probably need to have two solar panels in order to power my project. This was my second prototype for the solar panels.

After consulting teachers and the internet, I decided that I would connect the two solar panels to my motor with a series circuit instead of a parallel circuit. This means that one electrical current would run through the whole system in one path (unlike a parallel circuit, where there are multiple paths) and there would be an increased amount of voltage sent to the DC motor compared to one solar panel. This means that the motor would rotate faster than before and have a larger possibility of turning the handle smoothly.

I used many websites as reference to help me find how to connect two solar panels together (and also if I should use a series circuit) in order to provide me with twice the amount of energy:

MLA Citation: Punyani, Veenu. “How to Wire Solar Panels in Parallel or Series.” HES PV, HES PV, 29 Oct. 2014, hespv.ca/blog/wire-solar-panels-parallel-vs-series/.

MLA Citation:“Connecting Solar Panels Together For Increased Power.” Alternative Energy Tutorials, Alternative Energy Tutorials, www.alternative-energy-tutorials.com/energy-articles/connecting-solar-panels-together.html.

We first connected the electrical wires of the solar panels to their negative and positive terminals using electrical tape, so we can still easily remove the wires if we made a mistake (this was the second prototype for the electric solar panels):

It successfully worked, and the handle spun more smoothly on the electric generator than before. To make sure that the system would work more well within my device, where the motor would also be burdened by the pulley system, I cut off the extra parts on the handle, so it would become lighter in weight.

One of the criteria that I identified at the start of the project was to consider environmental impact. I tested the solar panel and motor a few more times to make sure that the motion would be fluid under direct sunlight, with the handle at the same place on the rod each time; it was indeed able to do that, so it means that my project considers environmental impact through using a renewable energy source to power it.

As my final and third prototype for the solar panel system, I soldered all the terminals together, and attached the solar panel system to my device container using velcro tape.

Here is a video of it on my device with the pulley (sunlight replaced by LED light): Movie on 1-18-19 at 3.05 PM

Pulley system and drum (vertical boards, pulley, string and drum):

As the final part of my device, I mostly worked on the pulley system and drum of my project. This is the section that will mainly be the part of my device that transfers the light energy and electrical energy to mechanical energy and sound energy. I didn’t really do specific prototypes for this system because of time constraints, but I modified it throughout the process.

As I constructed the pulley system, I mostly just followed my model sketch. However, I refined this section of the product along the way so that it would burden the electric motor of the device less. For instance, instead of just using a wooden dowel to be inside the pulley wheel, I used a dowel encircled by a plastic straw to decrease the amount of friction between the pulley and stick. Additionally, I used a thinner, wool string (the “cable” of the pulley system) so the electric DC motor would use less effort as it pulls. Another thing that I did was add stoppers made of bendy pipe cleaners beside each end of the pulley wheel to keep the wheel from sliding back and forth across the dowel.

For the pulley system’s load, I had changed it from a rubber ball to a big bolt nut, something lighter than before. The nut perfectly balanced the system because it wasn’t too light so that it was just pulled towards the pulley and it wasn’t too heavy so that the motor wouldn’t be able to move.

As for the two vertical wooden boards that are part of the device, I made them much shorter than the planned design because I felt like it would strain the motor again if it had to pull the load with an extra distance and height. Because of this, it was no longer needed to create a cardboard shelf for the drum or else the drum would be too tall.

On the other hand, for the drum, I constructed it using a cut balloon and a recycled soup tin-can. I wanted to use materials that considered environmental impact, so I found this tin-can at home to add to that. When I attached the drum to my device, I used duct tape instead of hot glue, because the hot glue would cause the pressure inside of the metal tin-can to build and explode.

Mostly for what I’ve done while designing the pulley system of this device, is to make sure that the electric motor can coordinate well with my system. By doing so, I can create a better experience for my clients (children) when they can see an obvious process of energy conversion within my design. Basically, this can help me to reach my main goal of educating children about energy conversion.

Here are photos of what the complete device looks like from behind after I attached the pulley system to the rest of the design (so you can see the pulley system more clearly):

Attached below is a revised sketch of my original model based on the changes I made throughout my designing process:

When I finally tested the first prototype of the device (the photo of this is the one above the sketch) it was able to meet a few of my previous criteria. The cardboard container was durable and steady as the motor rotated, I was able to use a renewable energy source to power the motor, and several materials (tin can, solar panels) that were consisted of this project considered environmental impact. It was pretty aesthetically pleasing and not too crudely designed as I measured before I cut all my materials.

However, the only thing wrong was that pulley system wasn’t able to move as expected. I was testing this using my criteria of whether this device would work and show energy conversion. It did not work and the motor did not move at all; one of the problems that the device faced was that the motor did not have enough power to pull the load of the pulley system.

Here is a video of the device under LED light: Movie on 1-18-19 at 3.25 PM #2

(From this video, you can guess the energy conversion process my device shows, which is light energy to sound energy. The device collects light energy from its solar panels and converts it to electrical energy through the motor. It then transfers the energy to the pulley system as mechanical energy, then uses gravitational energy of the load of the pulley system to create sound energy from the drum of my device)

Even though I tried to lift some burden on the electric motor before by changing other parts of my design, I decided that the problem was the motor and the solar panels itself. The solar energy received from the two solar panels was not enough to power my whole device, and this caused the motor’s rotating strength to be weaker than what the pulley system needed in order to pull the load.

What also suggested this was the feedback gathered from a user (Annie) of my toy: “This project is very creative, but one way this pulley system sound generator can improve is that the metal bit (bolt nut) can bounce on the drum with smoother movements. However, I believe that this can be done if the solar energy received from the solar panels can increase.”

My solution for this problem would be to wire another solar panel along with the initial two (attached using velcro), it would just be another addition to the established series circuit and I would lengthen the cardboard the solar panels are attached to to give it space. If I added this extra solar panel, it would contribute more solar power for my motor and give it a stronger spin.

I would probably need  longer wires to connect the two far-ended solar panels on each side to the terminals of the DC motor though.

Here is a plan for the solution that I drew:

In spite of this, I did not have enough time to operate my plan for a second prototype of the device, so I was forced to complete this project with only two solar panels.

In conclusion, regarding the creation of my project, I followed the process of creating prototypes, testing the prototypes using criteria, gathering feedbacks from users. Then using the test results and feedback, I made a plan to optimize my design even though I did not have time to actually complete the solution. I felt like I learned a lot because of this project, and the experience was rewarding!

What I’ve decided to make is a toy that converts light energy into mechanical energy and sound energy; the toy that I want to create is mainly complete with a pulley system, solar panels and an electric motor.

Specific Materials:
1. 2 Solar Panels (or enough to power the electric motor, taped onto cardboard box)

2. 1 Electric Circuit (placed within cardboard box)

3. 1 Electric Motor with a spinning rod (placed within cardboard box)

4. Large cardboard sheets

5. 2 skinny wooden boards at least half a meter long (50 cm) (glued on to either side of the box)

5. Wooden dowels (lengths enough to complete more than a meter) (connects pulley system with wooden boards using glue, is the rod that spins pulley system)

6. Tin can or any container similar to a tin can (used to make drum)

7. 1 balloon (skin of drum)

8. 2 metal rings with a radius of around more than 2 cm (to spin the rod of the pulley system)

9. 1 plastic tube with a length of around 4 cm (spins the string of pulley system)

10. Small wood scraps or pieces (used to make handles glued onto electric motor)

11. White paper (A4) (used to make tags)

12. Synthetic string (not wool or ones with coarse surface, the string around the pulley system, winded around the plastic tube)

13. 1 rubber ball (tied to string)

14. 2 rubber bands (used to attach balloons to tin cans)

Adhesives: Wood glue and tape

Click on link below for the PDF file of my model or you can just look at the picture below (the PDF is a bit slow to download because the file is big):

DSCF3594

Plan:

Thursday:

1. Cut out the cardboard and create the box that contains the electric motor, circuit and solar panels.
2. Using the leftover cardboard, create the small box that will hold the electric generator.
3. Put solar panels, electric motor and circuit into the initial model.

Monday:

1. Fit the wooden boards onto my cardboard box
2. Fit small piece of cardboard onto the wooden boards

Wednesday:

1. Complete the pulley system (wheel and ball)
2. Attach pulley system to wooden boards

Friday:

1. Create small drum using a container and balloon
2. Create small tags to stick onto the device
3. Attach rubber ball

    Several products have already been invented that have the same purpose, such as the hand-held generator (which converts kinetic energy into electrical energy) which causes a light bulb to light up after turning the handle of the device multiple times, or bracelets with UV beads that change color under light (light energy to chemical energy).

      Source: Alexnld.com “DIY                              

Source: RoyTecTips from YouTube “Bracelet UV Changing Color Bead”

    The criteria that must be achieved for this project is that the final product, as mentioned above before, must be able to show and educate the energy conversion and transferring processes from physics and must be safe and suitable towards young children. The toy should also be environmental friendly as well as durable.

    In order to decide what type of product to create, I have researched through some ideas, other than the two above, that have already been invented in order to gain inspiration for my project.

    The first interesting idea that I came across was the elastic car, which is a car that is self-propelled by the twisted elastic band (which contains potential energy) in its center. The energy conversion happening within this device is the process of converting elastic potential energy to mechanical energy, which causes the wheels on either side of the car to turn. Initially, this car does show the energy conversion process and looks safe for children. It also considers environmental impact, since you can recycle unwanted DVD disks and credit cards to make this product. The only con is that it does not show the conversion of a renewable energy source to electrical energy since it doesn’t require one, and it isn’t too aesthetically pleasing plus durable with a rough design.

   For this one, I find the idea of using simple elastics to create motion very interesting, so I might use this in my final product.

    The next evaluated design is the wind turbine energy generator, which is a machine that can generate electricity to produce light by a motor that is spun really fast from moving air or wind. The energy conversion that happens within this device is kinetic energy to electric energy and light energy.

    This device, unlike the first one, took a renewable energy source and converted it into electrical energy to produce light. It shows the energy conversion process and is quite safe for children; it looks good in aesthetics but the process of creating one consumes a lot of time that will not suit into the schedule set for us to finish this project. For this one, I really like the idea of mimicking a wind mill to produce electrical energy, which could also be an inspiration to some components of my final project as well. I could maybe use the idea of a fan converting the energy.

    The third design consists of multiple long sticks with guitar picks attached to each end that protrude out of a ball capable of rotating. The sticks, as they spin, will be able to pluck stretched rubber bands across a separate object (similar to string instruments) and create sound. It’s energy conversion process starts with mechanical energy from the ball’s sticks to sound energy of the separate object. Even though, frankly, the device was crudely designed in the video, I found it interesting because it included sound energy, a type of energy that I never correlated with my initial ideas for the project. The design wasn’t too complicated and the materials could also be recyclable.

    Additionally, the fourth idea I came across is the “electric generator“. This design creates electrical energy from the continuing rotating motion of the wheel next to the lamp. The energy conversion process shown here is mechanical energy to light energy. The advantages that this product possesses is that it can be environmental friendly (since its materials can consist of recycled DVD disks and so on), quite aesthetically pleasing, and safe for children. It also easily teaches energy conversion since the effects of the rotating wheel on the lamp is instantaneous and obvious. The downsides to this project is that it requires a complicated array of  materials to construct (that are possibly not available in China) and it would take up to much time to complete. One thing I could use from this design is the idea of using motion to generate electricity; I can even use some kind of renewable energy source to do this.

    The fifth device I came across was a pulley system, which transfers mechanical energy to gravitational energy (the bucket is higher from the ground). One of the project’s advantages is that the system isn’t too hard to create and it can be environmental friendly. It’s safe for children, and can teach physics as well. It can be made into something that is aesthetically pleasing and functional. The only disadvantages this project possesses is that it isn’t really that complicated and interesting as a whole, even to the targeted audience, children. I could maybe only use some specific portions of this device, which is the pulley system that moves objects up and down.

    The sixth and final device that I found was a solar-panel powered car. (1:47 to 5:32) The biggest advantage of this device is that it turns a renewable energy source (light energy) into electrical energy. It also looks quite eye-pleasing and would easily be able to teach children about energy conversion. It is also safe and durable as a toy, and it considers environmental impact since it uses a renewable energy source. The only downside to this device is that it is too complicated to make within the time constraints. However, I do want to use the idea of using a solar panel so I would have to learn how to connect the solar panel to the device and make it move in order to incorporate solar panels into my product.