Final project part 2

On Friday we presented our idea to our client.  We got some good feedback from the child studies center.  

GATHERING SUPPLIES

On Monday we were ready to gather our  materials.

The things that we needed for our project are:

Construction Paper and Post-it notes

delrin sheet

delrin rods

Arduino microcontroller

LED lights

Breadboard

Transistors

RGB LED light strips

Last week, I suggested that rather than using the LEDs that we have in Engineering Lab and dealing with all of the wiring and soldering, that we should get LED light strips, because I saw a rather creative use of microcomputer-controlled LED lights strips to create a light and sound show in a old grandfather clock.

Nanaki was pretty enthused about the labor-saving and cool-ness factor of LED light strips as well.  We wanted to buy LED light strips.  Nanaki looked at light strip prices and options and we wanted to get digital light strips because we wanted a proper light show. 

We submitted our request to order the things that we wanted for our project.

MECHANICAL DESIGN:

When we came up with our current plan, we decided to split up the work into mechanical and electrical/programming.  

Although I'm a CS major, I decided to tackle designing the mechanical aspect because I really enjoyed CAD in Solidworks.   All the construction, relations and dimensions make my pieces perfectly constrained and so beautiful and proper.  *sigh*

Although I expect that both the feedback/control and the mechanical side will have their challenges in design,  The mechanical construction will be much more time-consuming than the electrical/programming portion, due to the plan to heat stake all of the spacers and dowels, which should be around 56 at the very least for just one array.  Still a better deal than soldering twice as much for a button array.  besides it would be much easier to debug.

Frankly, I've been thinking about the mechanical design of the toggle in the window frame ever since I came up with the idea to replace the button toggle 

My toggle mechanism will consist of a back board to hold things together, two dowels attached onto an sliding toggle that can be toggled back and forth, front piece containing a window to the sliding toggle, and a spacer that will prevent the front and back pieces from collapsing together and restricting the movement of the toggle.

On Monday, I made a physical prototype, putting my plotting to cardboard.

This prototype would would only include one window with one toggle good for one toy, so that I could test the design of one window without constructing the whole array which will have lots of 

It confirmed most of my design.  All of the dimension choices look pretty good.  

This is it being slid into the other position:

It moves pretty good.  It reminded me that I had to remember to make the height of the slider from the base of the dowels bigger than the maximum height of the window in the front plate.  

One revelation that I should have seen coming was that the toggle didn't even run on the track because the dowels kept the whole toggle suspended above the track.  Really, I could have imagined in my mind, but alas, good thing for prototypes, eh? 

of course the real thing will have proper spacers and will have little divots that would catch and keep the dowels and thus the toggle in place in the event of an accidental little jolt. 

On Monday I started actually constructing all of the pieces.

Class started at 1: 30 and I didnt' leave until 5:30 because I was on Solidworks creating my designs.

I made a lot of changes to my designs,

I love thinking about and remembering all of the dependencies.   

I have 4 pieces and every time one little thing changes one piece, at least one other thing on another piece needs to be changed. 

In the end I came up with the designs for the back plate, the front plate with the window and the toggle, with space left to insert a Delrin toggle.

It was enjoyable, but it was kinda lonely, because pretty much no one was left in the engineering room after class when I was working on the creating the Solidworks design. 

FRIDAY:  FINISHING DELRIN FINAL PROTOTYPE: 

Friday, I continued thinking about what thickness of Delrin I wanted to use.  Ideally, I would use as thin a Delrin as I could that could remain rigid over around 15 cm.  However another consideration is that the Delrin must be thick enough for me to heat stake the pieces together without too much warping, and as I was looking at the 1/16 Delrin, although it was very thin and looked rigid enough over 15 cm, it looked to be far too thin to heat stake accurately. 

My partner actually suggested 3D printing the front and back boards.  My problem with that was that the array would be around 11" by 11" which would not only be a little too big for the 3d printer, but would use up so much material as to be too expensive.   Additionally, inserting the inside toggle int oa 3d printed front and back when you can't remove the front and back would be a little tricky.  Mostly it was the cost prohibition.

I continued working on my beautiful Delrin designs.  

The back 

spacer

 
toggle, with two hole cutouts for the dowels

front piece

I thought of using construction circles to represent the dowels as they would rest in the divots in the front piece. make it a little more complicated than it otherwise would be, but I think it will be worth it if I ever have to move change the little divots 

Just look at all those relations!  :D

It may be that the little divots aren't deep enough to prevent the dowels from coming out of the divots, but if that proves the case, because the construction with all of the relations between the elements were well thought out, it should be a cinch modifying the depth of the divots, and the window frame.  :D   Wonderful are relations. 

LEARNING TO SOLDER. 

What is soldering?  Soldering is connecting two metal pieces of metal with another metal glob.  Okay, its more refined than that suggests.  you might want to connect two metal pieces, just because you want to connect, them.  Or you might want to connect the two metal pieces together so that an electrical charge can pass through it, and carry power, or a signal or other wonderful things that the flow of electrons can carry.   

In the latter case we use some soldering metal that contained lead to connect two metal pieces together, because, as it happens, lead is a good conductor of electricity, and plus, it has a low melting point, making it easy to melt over the two metal pieces to join them when the lead cools.

This is how you solder.  You get a really hot stick, with a very hot tip, and use it to really heat up the joint, hot enough to melt the solder in the correct way and not hot enough to heat damage the components at the joint.  When you have the joint and the solder stick just hot stick just hot enough, then you press a wire of lead to the joint at the tip of  the hot stick and melt your solder in to a nice neat puddle that you get a nice concave curve connecting the two two pieces which you can get because surface adhesion will give you a concave meniscus. 

One should also exercise good judgement in soldering, like fanning away bad fumes, and being really careful of hot metal sticks.  >.<