Rise of the Cubby Buddies

Project Idea:

Magnolia, Vivian and I created a Cubby Buddy - a pull out stool from the bottom cubby for the children to step on in order to reach the top shelf of their cubby.  Because the children in the Child Study Center are young - two to five year olds - and short, our intentions were to create a device simple, easy to use, and convenient for children.  With the Cubby Buddy, children can still place their boots or shoes in their cubby without the Cubby Buddy interfering with space or inconvenience issues.

Before building the Cubby Buddy, we understood that in order to build a working Cubby Buddy, we would need to build a cubby with it.  However, we only built the bottom two sections of the cubby (for boots and coats) since we did not need the top section for anything.

We also understood that the children are top heavy, and having them kick the Cubby Buddy would reduce injuries as they would have less chance of falling over.  Kicking the Cubby Buddy would also increase and foster independence as at an early age, and they will begin learning to complete simple tasks on their own.

Week 1 & 2:

We proposed the Cubby Buddy idea and drew our ideas out on paper after visiting the Child Study Center, taking measurements and observing the children interacting with their cubby.

Week 3:

Our next step was to calculate dimensions and cost, and to research cheap materials to create our wood prototype.  In the meantime, we created a rough cardboard prototype with exact dimensions.  While waiting for materials to arrive, Magnolia wrote the code for our lights we would use for the cubby.

Week 4:

Week 4 commenced the building of our actual cubby and Cubby Buddy.  However, once we received the wood from Home Depot, we came to the grim realization that the dimensions of the wood was a little smaller than the actual dimensions and had to recalculate and scale the cubby and Cubby Buddy.  The materials we used for the cubby and Cubby Buddy were:

• Wood
• Drawer Slides (2 pieces)
• Nails (3/4 in, 2 in)
• L-Shaped Metal Supports (2 pieces)
• LED Lights (green, white)
• Arduino and Six Batteries

Week 5:

After building the cubby and Cubby Buddy, we added a button, lights, feet and top box.

The button was placed behind the Cubby Buddy in the back of the cubby.  When the Cubby Buddy was all the way in, the button would be pressed.  However when the Cubby Buddy was pulled out, the button would un-press and lights would begin to flash reminding the children to push the Cubby Buddy back.

There were two location for the lights - one on the edge of the wood above the coat section of the cubby and some behind a drawing of a person kicking the Cubby Buddy that Vivian drew hanging in the middle of the large section of the cubby.

The feet of the Cubby Buddy was a piece of wood with delrin glued to the bottom of that piece of wood.  The feet is drilled to the edge of the Cubby Buddy on the bottom so when the Cubby Buddy is pulled out, the weight of the children won't bend and mangle the drawer slides.

At the top of our cubby is a wooden box made from scrap wood that contains all the wires, Arduino, soldering board and batteries.  Ideally, with one of the cubbies in the Child Study Center, the box would be on top above the third shelf.  The children would not be able to touch the materials inside the box.

Improvements (2.0):

With more time and less restrictions for the project, we would find a way to put the green lights on the cubby without having wires and black electric tape on the cubby show.  We would also order a set of cheaper drawer slides that was said to be able to withstand more weight.

Our final model of the Cubby Buddy totaled $34 for the wood, drawer slides, soldering board, LEDs and L-shaped supports.  With more time, we could potentially find cheaper materials and cut the cost down.  With 37 cubbies in the Child Study Center, a cheaper cost increases the amount of Cubby Buddies built.

Final Thoughts:

Our Cubby Buddy will one day save many children the stress of not being able to reach the top of their cubby.  With such an invention, a simple yet practical invention, children can also learn to become more independent while kicking their Cubby Buddy and learning to push it back in once finished using it.


Now that our final project has come to an end, I am grateful for all that I have learned: coding, sautering, using the wood cutter, drilling, and most importantly, thinking outside the box.  Coming into the class late January, I would not have believed this was possible to complete in four weeks.  Upon completing this project, I am now more confident in my abilities in finishing projects that I start, and with engineering, particularly mechanical engineering.  Making this Cubby Buddy has assured me to continue engineering despite not having an engineering major at Wellesley.  With the skills I have acquired this semester, I hope to pursue and chase my dreams and continue with mechanical engineering.

Cubby Buddies Week 5

This week, after finishing a model of the Cubby Buddy, we added the technical parts for the Cubby Buddy including lights and a button, and included a bottom piece to the Cubby Buddy we call "feet."

Because the Cubby Buddy is not the length of the depth of the Cubby, we had to make a few adjustments with the button.  First, we found a larger button, and second, we added a small plank of wood behind the button for the Cubby Buddy to fully press on the button when closed.

Our final product can withstand the force of fully grown adults and can be roughly kicked in and out.

Lights:

We had to add lights to the top front of the cubby as well as lights behind a photo Vivian drew to remind kids to remember safety and push or kick the Cubby Buddy back in place once pulled out.

Our challenge while making the lights was the sautering.  And like Christmas lights, if one goes out, all will because we wired them in series with one another.

Our second challenge once completing making lights were to install them onto our cubby.  We had to drill holes in corners of the cubby, which with a big drill, was difficult.  We fed long wires through the holes and sautered them onto a small breadboard.  The breadboard, arduino and batteries lie in a wooden box we made out of scrap, leftover wood (right picture).  The battery pack is not covered or easy access in case new batteries are needed.  The box is used to hide a majority of the wires so kids won't be distracted or tempted to touch and accidentally hurt themselves.  The box sits on top of the entire cubby out of reach for the children.

Here is a video of our Cubby Buddy in action with lights.

Button:

Putting wood pieces in the back of the cubby and inserting the button with wires sauntered on took a lot of trail and error wood cuts and button placement.  After Magnolia sautered the wires onto the button, in order to feed the wires to the top of the cubby and connect them to the breadboard, we had to cut a wedge out of a piece of wood in the back of the cubby for the wires to fit in the corner.

After jamming the button into the back of the cubby, we realized when the Cubby Buddy was pushed all the way in, the button was not fully pressed.  Using a thin sheet of cut wood, I glued it to the back of the cubby for the button.  Now, the button is fully pressed when the Cubby Buddy is pushed in.

Feet:

By adding feet to our Cubby Buddy, the weight of children will not force the drawer slides to bend.  We cut a U-shape out of a slab of the wood and attached a sheet of delrin to the bottom of it.  The U-shape is to reduce cutting down the space for children to put their shoes in the cubby.  The delrin is to reduce friction between the feet of the Cubby Buddy and the carpet floor in the Children Study Center.

Cubby Buddies Week 4

Week 4 was all about building the cubby and Cubby Buddy.  Materials we used for the cubby and Cubby Buddy were:

• Wood (11/16 in)
• Drawer Slides (2 pieces)
• Nails (2 in, 1/4 in)
• L shaped support (2 pieces)

Once we got the wood, Magnolia, Vivian and I immediately started cutting wood and drilling and screwing pieces together.

However, our first problem was the sizing of the wood.  The cut pieces of wood we received from Home Depot was smaller than our actual measurements.  Because of this, we had to rescale our cubby and Cubby Buddy based on the sizes of wood we were provided with.  Below are measurements of the new cubby and Cubby Buddy sizes.

In order to cut our wood planks into smaller pieces for the Cubby Buddy, we used a table saw in the wood shop.  With different sized and shaped pieces of wood, there were many different ways of cutting the wood: standard sliding wood past the blade, using a metal guider for pieces longer than wide, and using another object to push the piece past the blade.

The first task we did after cutting was attaching the drawer slides.  With just Magnolia and I, we were both just beginning to learn how to use the a drill.  Connecting the drawer slides was extremely difficult as we had to use 1/4 in nails and drill them through specific holes.  Once we attached the drawer slides to both the cubby itself and the side of the Cubby Buddy, we began connecting all sides of the cubby together.  With two inch nails, this task proved much easier.  The one thing we had to keep in mind while drilling was not to splint the wood.

The next day, Magnolia, Vivian and I met to finish installing the L supports for the insides of the Cubby Buddy and the tops and bottom of the cubby and Cubby Buddy.  Using a scrap piece of wood, Vivian drilled a handle onto the Cubby Buddy.  The handle stretches the length of the Cubby Buddy and is about an inch long, small but large enough for a child's hand or foot to reach under and hook onto.

Here is our finished product of a cubby and installed Cubby Buddy.  Next to the wooden model is our cardboard model.

We have not yet included the LED lights reminding kids to push the Cubby Buddy back in, or the button determining whether the Cubby Buddy is pushed in or pulled out.

On Friday, all CSC groups met with Becky.  While presenting our idea, we noticed when the Cubby Buddy is pulled out, it is 11/16 of an inch off the ground.  With the weight of a children on it, the drawer slides could easily bend and weaken.  Amy suggested attaching a sheet of delrin onto the bottom of the Cubby Buddy that would act as feet.  While in the CSC, we also noticed the cubbies on a carpet surface, and understood that delrin, rather than wood, would slide better on carpet.

Our second issue was the button placement.  Our original idea was to place the button on the side near the end of the cubby.  When the cubby was pulled out, the button would un-press, and when pushed back in, would press again.  However, we realized that once the button was unpressed, the Cubby Buddy would only hit the side of the button and would not push back in.

Our last issue was the possibility of items stuck in the back of the Cubby Buddy.  The depth of our Cubby Buddy is about an inch shorter than the depth of the cubby.  This increases the chances of items in the back blocking the cubby from going all the way in.  We will put wooden pieces in the back on the cubby to decrease the likelihood of that.

The next step for our Cubby Buddy is to install lights and the button.  We will drill holes in the cubby for wires and tape them along the corner.  The breadboard and power source will be placed on the top of the cubby.

Cubby Buddies Week 3

Week three marked the beginning of a cardboard prototype and research for a final model.

We created a rough cardboard prototype of the cubby itself but cut out close to exact measurements for the cubby buddy.  We put together the bottom cubby and middle cubby for the coats and added handles for precaution.

Larry suggested L-shaped metal supports for the insides of the Cubby Buddy which we found online for about $2 apiece.  We included cardboard cutouts of them in our prototype in the bottom right picture.

In our cubby prototype, we have included the supports, handle for kids to pull the cubby out, and the drawer slide on the sides of the Cubby Buddy.

Our initial idea for the handles were for them to look like those on the cubby.  Upon further discussion, we concluded oval shaped holes in the cubby would be safer for fear of the kids running into the handles.

In the middle picture below, we played out the pieces of the cubby and Cubby Buddy in SolidWorks to calculate the total area of wood needed for the entire cubby and Cubby Buddy.

We are putting lights behind a picture to put on the back of the coat block of the cubby.  The picture shows a person kicking the cubby.  When talking to Becky, she suggested having the children kick the cubby back since they are top heavy and it will be easier and safer for them.  This shows that the children they are allowed to use their feet and can be rough with the cubby.


To further the process with the lights, we wrote a simple code and connected LED lights onto a breadboard and an Arduino.  We used a red, green, and blue LED and found that the Blue shone with the largest radius.

In the video, beneath my finger is a button.  When the button is pressed, the lights do not flash, but when the button is not pressed, the lights start flashing.  The lights were set up to imitate what our final version with the picture would look like.  When the cubby is pushed all the way in, the button would be pressed, but once the child pulls the Cubby Buddy out slightly, the lights would start flashing to inform and remind the kid to push the Cubby Buddy back in.

In addition to using an Arduino, Magnolia, Vivian and I learned to solder wire together using a soldering iron and some led.  We soldered a mini robot that when a battery was inserted, LED lights acting as eyes would begin blinking rainbow colors.

At the end of this week, we came to a conclusion that although our project does not contain a lot of feedback and control, our project is just as time consuming with all the physical building of the cubby and Cubby Buddy.   Our project is more on the side of mechanical engineering.

MATLAB: Thermal Systems Part 2

Heating Curve:

Using a given code in class, test_thermal.m, we ran our code producing the graph on the right.

Our graph ran for 300 seconds and paused every half second to plot the graph.

1: Calculating The Physical Constants

Using test_thermal.m from above, we took the slope at the beginning of the curve and the initial and final temperature to calculate the time constant: t = Rth*C.

• Rth = (deltaT / P) = ((R * deltaT) / V^2)
• used: change in temperature, voltage
• Rth = 6.9
• C = (P / slope) = (V^2 / (R * slope))
• used: voltage, resistance, slope
• C = 16.2
• t = 112.1

Our calculated time constant was 112.1 seconds and the temperature at that time should be 334.4 K.  The actual temperature from the graph above at 112.1 seconds is 338.6 K, which was a bit higher than expected, although still approximately 63.2% of the final asymptotic value.

2: Simulation

We modified the heatsim.m code by putting in our calculated values from above and resulted with the graph to the right.

The generated graph had a very similar curve to the our experimentally measured results from the initial test_thermal.m graph.

3: Bang-Bang Control

Magnolia, Vivian and I modified test_thermal.m to contain bang bang control with a target temperature of 340 K.

Compared to the behavior of last bang bang simulation, this simulation reached a close 340 K through smooth increase.  In Thermal 1, our bang bang started and stayed at 0 for a bit, immediately increased with no warning and once goal temperature was reached, began dropping and increasing in little segments.

Above shows the code and the graph produced from the graph.  Below shows the values of the temperatures at the plateau of the graph.

4: Proportional Control

error = target state - present state
setpower = Kp x (target - T)

We modified a second test_thermal.m code to include proportional control.  We ran the code for three different proportional gains: 0.05, 0.2, 0.5.  The smaller the proportional constant, the smaller the increase in temperature.  The larger the proportional constant, the more significant the increase in temperature of a system.


The proportional constant cannot be too big or it will act like bang bang control and will basically be on full power from the beginning and will stay on full power until when the target temperature is reached.

The optimal proportional gain constant is between 0.2 and 0.5 for the target temperature can be reached while using the power efficiently.

Reflection:

This activity allowed us to see the differences between simulations and actual experiments.  Although the numbers and graphs produced were very similar, differences were ubiquitous.  There are many limitations due to the natural nature of Earth causing the difference between actual and theoretical data.

Examples of thermal systems can be seen in many things we do everyday including heaters and air conditioners.  Having some control over them is important in creating and designing safe devices.

Cubby Buddies Week 1 & 2

Task:

Magnolia, Vivian and I are to create an object for kids to easier reach the top shelf of their cubbies.  We are to incorporate feedback and control into our final design.

Cubby Buddy:

After taking measurements from the cubby at the Children's Study Center, we decided to make a pull out stool at the bottom of the cubby while keeping the space large and un-touching the shoes and boots below.

To the right is a drawing with measurements of the cubby sizes.

Issues:

Safety is the main issue we need to keep in mind while designing this cubby.  When the kids pull out their cubby, having it out is not safe with others walking around in the hall.  We also need to ensure they will be safe when using the Cubby Buddy.

We also need to take in mind maximizing space when creating this Cubby Buddy.  With a pull out device, it can easily become too bulky.

With 37 cubbies in the Children's Study Center, minimizing cost will be a struggle.  Although for this project we are only creating one final Cubby Buddy model, if this were to be used in the Children's Study Center, we would need to keep the cost down.

How It Works:

Handles:

Kids are allowed to pull out the cubby by themselves.  There will be a curve shaped handle that will go across the entire length of the cubby.

For safety precautions, we added handle bars to the side of the cubby for the children to hold on to while stepping on top of the cubby.  By analyzing the average children height, we will determine where exactly and how many sets of handle bars to put on the cubby.

Sliding & Locking Mechanism:

A wheel will be attached to the end of each side of the Cubby Buddy and will slide with the guide of a track connected to the side of the cubby.

When the cubby is pulled all the way out, the weight of the child on the cubby will keep the cubby from sliding back in on its own.

However, when the cubby is pushed back in, our initial idea was to have an elastic plastic shaped with half circles for the wheels to slide and lock into place when pushed all the way in.

Second Idea: there will be two wheels, one wheel which will not be able to move much at the end of the cubby keeping it in place.

Lights:

For our feedback and control, we will 1. use an ultrasonic sensor at the back of the cubby to sense how far the cubby has been pulled out.  2. We will use a button on top of the Cubby Buddy, and when stepped on, green LED lights attached to the edge of the cubby and below the board of the main cubby will turn green.  Once the kid steps off the button, after a given second or two with the unpunished button, red LEDs will turn on behind a picture informing the kids to push the cubby back in.  We incorporated visuals as they might be too young to understand why green generally means go and red means stop.

In the picture to the right, the kid's height is exaggerated to show where the lights would be put.