Will you be my Cubby Buddy? (The Grand Finale)

Now presenting our final project:

Cubby Buddies

designed and created by Rachel Hwang, Magnolia Pak, and Vivian Yu

 

At the Child Study center many children are unable to reach the top shelf of their cubbies to store their art projects and other creations due to their small stature. Our Cubby Buddy remedies this issue with a sliding step that not only enables children to put away their art projects on the top shelf but also fosters independence.

The Cubby Buddy is activated by pulling it out with a foot, then stepping on top and embracing this new power that comes with height and stepping off once desired and kicking the Cubby Buddy back in.We designed the Cubby Buddy to be used with feet rather than hands because child are top heavy and have a natural instinct to kick things in.
There are also measures to remind children to kick the Cubby Buddy back in, including a kick sign and lights that light up as soon as the Cubby Buddy is pulled out.
Cost of the Cubby Buddy: Wood ~$14, Supports ~$5.50, LEDs ~$2, Drawer Slides ~$8.50, Soldering Board ~$4. Total Cost: ~ $34

The history of the Cubby Buddy:
Week 1&2: Brainstorming
We decided that we wanted to work on the step cubby project because it was a problem that was different than all of the other groups and was a problem that the Child Study Center always had.
In further brainstorming, first we looked at collapsable stairs: much like the ones used for attics or pets, but we soon decided that it would be to complicated and more unsafe for the children due to too many moving parts.So we stuck with an idea similar to what we started with: a drawer type sliding step. Now presenting: Cubby Buddies!

Week 3: Cardboard Prototype and Lights code
This week we started making a cardboard prototype of the cubby, planning the wood prototype, and also figured out the code that we need for the lights.
Cardboard Prototype:
Since we didn't have any wood at first we made a cardboard prototype to visually map out what we need to do.

Lights Code!
Now that we know we are using a button, using our past ENGR 160 skills, it was pretty easy to make a code that will tell the lights to turn off then the button is pressed (because the cubby buddy will be in the cubby and pressing the button) and when the button is not pressed the lights will turn on (because the cubby buddy will not be pressing the button since it is out of the cubby)


Week 4: Wood Prototype
This week we got our wood to build our final prototype of the cubby and went to a checkup with Becky about our progress.
Final Prototype logistics:
We got our wood! Unfortunately it is not exactly the same size as we specified, so we had to redo some math to make sure all of the pieces fit together. We also learned how to drill and cut plywood (and splintered a lot of wood). Building a cubby took way more time than we expected, but shockingly the hardest part was drilling the drawer slides in, because of the precision required and the fact that the drill did not fit into the cubby much to our dismay.
 

Here's our wood cubby next to our cardboard cubby!

We added the L brackets to the Cubby Buddy to insure it's stability and to increase the load it can take. 

We also made a sign, as per suggestion of last time we made a sign to tell the children to kick in the Cubby Buddy when they are done using it, we also decided to make the sign light up so it is easier to see and easily distinguishable.

Our kick sign

Week 5: Putting it all together: adding bottom piece, testing buttons and lights, and soldering
This is our last week working on our Cubby Buddy before the final presentation! And the Cubby Buddy team is working on putting all of the pieces of our project together.

Horray it works! and can support one whole Vivian

Bottom piece:

To maximize space for the children to put shoes in we decided to make the bottom support piece like a bracket shape so it will not interfere with any storage space at all. We also added a piece of delrin to the bottom to decrease the friction between the bottom piece and the ground because delrin has really low friction.















Here is a video of the bottom support in action:

Lights:
For the lights we decided we wanted a bunch of lights lining the the front of a cubby shelf and a light up sign. First we tried to individually light up all of the lights, but that proved impossible because we would have to control each light separately and we do not have enough arduino pins to accomplish that. Instead we figured out how to make a string of lights by soldering a bunch of LEDs to two strings of wire. (In other words we found out how to make homemade Christmas lights!)
Once we made the strings of LEDs we strung them on a part of the cubby and inside the paper sign.

First trial with string of LEDs SUCCESS! 

Button:
Here is the button that we are using to detect whether the Cubby Buddy is in the cubby or not, we placed it in the back of the cubby so when the Cubby Buddy is completely in the cubby it will be pressed. We also had to wire this from the bottom of the cubby all the way to the top of the cubby where the arduino is.

Soldering it all together:
Once we figured out how to wire everything, we soldered everything together and placed it inside a little box that we made (for the aesthetics).

And here is our Cubby Buddy in action!

Final impressions and thoughts!
I am really happy with our Cubby Buddy and Becky seemed ready to try to get one for the Child Study Center, so all in all I count it as a job well done.
But as it is with all projects, there is definitely room for improvement, I think one of the big ones is price. The Cubby Buddy currently costs about $34, which is a lot considering there are 37 total cubbies in the Child Study Center but it is also true that prototypes are bound to cost more than if it was implemented in real life. I also think that the lights probably are not all that necessary and if we were not given the control and feedback requirement we probably would not have made them. It's a shame that we don't have time to test it out in real time with the children because I also wonder if the children will just play with the Cubby Buddy instead of using it because of the blinking lights. Given more time I would also want to explore adding the handles we had in the first design to make this even more safe and accessible for children.
Looking at the timeline of our Cubby Buddy we have come really far from our first brainstorms, this long and arduous journey of splinters, soldering burns, late nights at the engineering lab is one that I will never forget. All I have left to say is: Will you be my Cubby Buddy?

Final Project Week 5

This is our last week working on our Cubby Buddy before the final presentation! And the Cubby Buddy team is working on putting all of the pieces of our project together.

Horray it works! and can support one whole Vivian

Bottom piece:

To maximize space for the children to put shoes in we decided to make the bottom support piece like a bracket shape so it will not interfere with any storage space at all. We also added a piece of delrin to the bottom to decrease the friction between the bottom piece and the ground because delrin has really low friction.















Here is a video of the bottom support in action:

Lights:
For the lights we decided we wanted a bunch of lights lining the the front of a cubby shelf and a light up sign. First we tried to individually light up all of the lights, but that proved impossible because we would have to control each light separately and we do not have enough arduino pins to accomplish that. Instead we figured out how to make a string of lights by soldering a bunch of LEDs to two strings of wire. (In other words we found out how to make homemade Christmas lights!)
Once we made the strings of LEDs we strung them on a part of the cubby and inside the paper sign.

First trial with string of LEDs SUCCESS! 

Button:
Here is the button that we are using to detect whether the Cubby Buddy is in the cubby or not, we placed it in the back of the cubby so when the Cubby Buddy is completely in the cubby it will be pressed. We also had to wire this from the bottom of the cubby all the way to the top of the cubby where the arduino is.

Soldering it all together:
Once we figured out how to wire everything, we soldered everything together and placed it inside a little box that we made (for the aesthetics).

And here is our Cubby Buddy in action!

Final Project Week 4

This week we got our wood to build our final prototype of the cubby and went to a checkup with Becky about our progress.
Final Prototype logistics:
We got our wood! Unfortunately it is not exactly the same size as we specified, so we had to redo some math to make sure all of the pieces fit together. We also learned how to drill and cut plywood (and splintered a lot of wood). Building a cubby took way more time than we expected, but shockingly the hardest part was drilling the drawer slides in, because of the precision required and the fact that the drill did not fit into the cubby much to our dismay.
 

Here's our wood cubby next to our cardboard cubby!

We added the L brackets to the Cubby Buddy to insure it's stability and to increase the load it can take. 

We also made a sign, as per suggestion of last time we made a sign to tell the children to kick in the Cubby Buddy when they are done using it, we also decided to make the sign light up so it is easier to see and easily distinguishable.

Our kick sign

Check up with Becky:
We talked about
Q: Whether or not we need the handles
ANS: Not necessarily, so we can cut it out of our plan (we will)

Q: How to make sure the cubby buddy does not tilt due to the cubby buddy not being level with the ground
ANS: We can add a piece that is attached to the bottom of the cubby buddy that will account for the difference between the cubby buddy and the ground

Q:Where to put the sign? Should we add more lights?
ANS: It should be okay to put the sign in the cubby buddy, and more lights could be helpful to make sure the children are alerted.

Q: Wiring and where do we put the arduino?
ANS: Putting the arduino on top of the cubby is our safest bet, and for the wiring, as long as the kids cannot grab it wires are fine.

Thoughts for moving forward:
Overall I think we're at a good place. We still have many things to do: including but not limited to soldering and wiring the arduino, testing the button placement, making a bottom piece to increase stability.

Final Project Week 3

This week we started making a cardboard prototype of the cubby, planning the wood prototype, and also figured out the code that we need for the lights.

Cardboard Prototype:
Since we didn't have any wood at first we made a cardboard prototype to visually map out what we need to do.

The full cubby

Our cubby buddy

A front view of the cubby buddy

On thing we realized was that we needed something to account for the slight height difference between the cubby buddy and the floor once it is extended out. We first tried to account for this difference by adding wheels to the cubby buddy but then realized that wheels are too big and cumbersome, so we decided to wait until we see the wood prototype to actually see if this difference is significant enough to add something.

Planning final prototype:
We talked about ordering materials for our project and realized that we would not only have to make the cubby buddy but the full cubby which is a lot of wood which adds a lot of cost. Our final cost is ~$50 so we have officially maxed out the budget...

You might notice that "Force Plate" is not listed on there, despite it being our sensor for our lights, we realized that 1. force plates are expensive 2. force plates are heavy and large, both of these factors deterred us from using a force plate. We talked to Xixi about this and after thinking this through we realized that we actually don't need a force sensor because we can just use a button placed cleverly in the back of the cubby that will sense if the cubby buddy is closed or open and use that information to tell the lights when to turn on.

Lights Code!
Now that we know we are using a button, using our past ENGR 160 skills, it was pretty easy to make a code that will tell the lights to turn off then the button is pressed (because the cubby buddy will be in the cubby and pressing the button) and when the button is not pressed the lights will turn on (because the cubby buddy will not be pressing the button since it is out of the cubby)

Final Project Week 2

This week we chose and presented our project ideas!

We decided that we wanted to work on the step cubby project because it was a problem that was different than all of the other groups and was a problem that the Child Study Center always had.
In further brainstorming, first we looked at collapsable stairs: much like the ones used for attics or pets, but we soon decided that it would be to complicated and more unsafe for the children due to too many moving parts.

So we stuck with an idea similar to what we started with: a drawer type sliding step
Now presenting: Cubby Buddies!

*cubby step is in 

Here is a more in depth version of the design:

We plan on making a drawer slide type mechanism with a locking mechanism that will keep the cubby buddy for moving while the children are on the step or when it is supposed to be in the cubby.
The Cubby Buddy will also have a handle on it so the children can pull it in and out with ease (just like a drawer!)

Control and Feedback:
For the control and feedback portion of the project we planned on putting lights up on the shelves that would light up green, yellow, and red when the children step on a force plate that will be on top of the step.

 ***BONUS ROUND***
Added Safety feature:

The handles will provide extra support and stability for the children for getting up or getting down the cubby buddy.

UPDATES AFTER PRESENTATION & BECKY'S FEEDBACK
To think about:
-Children do not easily associate colors of lights with directions because it is too abstract of a concept, therefore the color of the lights will not be useful indicators. Signs and pictures on the other hand are very useful and effective!
-Children are very top heavy, so making the cubby buddy usable with feet would be a very nice solution!
Positives:
- Handles are awesome! (you can never be too safe)
-It fosters independence! yay!
-Lights are a good option because they are not loud and distracting to the classrooms nearby.

Moving Forward:
Becky's comments really helped us put things in perspective for the children, moving forward we are going to think about making the handle easily used with hands or feet, get rid of the red, yellow, green lights, and think about putting up a kick sign to remind the children to put away the cubby.

Thermal Systems Part 2

This was week 2 of thermal systems on MATLAB
Last time we simulated a thermal system of a cup of coffee on a hotplate, this week we are working with a real life thermal system! By using: a heater (whose power we controled), a thermal reservoir (with a resistor in a brass casing aka a "heat sink"), and a temperature sensor/thermistor.

Deliverable 1. Calculate the physical constants: using "testthermal.m" (given) find the two parameters: thermal resistance Rth and heat capacity C.

According to our math, our theoretical time constant is a little higher than the true time constant, but this makes sense since we had to estimate when calculating the slope that was used to find C.

After we found the physical constants Rth and C we experientially measured the heating curve with these new thermal parameters.

Deliverable 2.We then modified our heat simulation from last week to fit our new thermal parameters

The simulation and the experimental are pretty similar even though they are scaled differently when we look at them closely the slopes are almost identical. The biggest difference is the the fact that the experimental graph does not start at an initial temperature of 0. The peak temperature for experimental is 335K and simulated is 327K which is a difference, but not significant enough to be too concerned.

Deliverable 3. We then started to experiment with different types of control, starting with bang bang we modified test.thermal.m to change the power supply based on whether the measure temperature is above or below the target temperature.

Table of peak temperature

Experimental Bang Bang

Simulated Bang Bang

The main difference between the simulated and the experimental bang bang is the extremity of the temperature change, which in part has to do with the scale and the long amount of time it takes to heat things up in real life. Both the simulated and the experimental show the temperature reaching the "peak" or "goal" temperature then bouncing back and forth, as expected with Bang Bang control.

Deliverable 4.Then we implemented a proportional controller for a target temperature of 340 K using Kp= 0.05, 0.2, and 0.5 W/K

Kp=0.05

Kp=0.2

Kp=0.5

Upon looking at the graphs we can tell that the system does not reach the control set point when Kp is small, which makes sense because of the nature of proportional control to correct more and more once it is close to the goal, but due to Kp being too small it never reaches goal, which means it cannot correct and will be stuck never reaching the control. In this specific example the increases are so small that it plateaus before it even reaches control.
Conversely when Kp is high it tends to overshoot the control quickly, but then it takes a while to find it's way back. Considering this knowledge and the graphs .2 seems to be the optimal gain for our system because it is a happy median between the small .05 and the large .5

Final MATLab thoughts!
This week's real life thermal systems was far more complicated than last week's simply because of the nature of real life systems, we sometimes forgot to wait long enough for it to fully cool down which lead to many inaccurate results that we thought was our code.