Week 18, Project Development¶

Applications and implications¶

From Nueval

For the week, the concept is the following

Propose a final project masterpiece that integrates the range of units covered.
Your project should incorporate:
- 2D and 3D design
- Additive and subtractive fabrication processes
- Electronics design and production
- Embedded microcontroller interfacing and programming
- System integration and packaging.
- Where possible, you should make rather than buy the parts of your project.

The following checklist is included to guide the work

This is an excellent set of questions, which I am using to guide the documenation on my final project page.

My project will deal playing cards with an interface for choosing the number of cards to dispense and the number of players. This concept has been implemented by others (see final project page), but I am starting from the ground up.

In short, at the moment I have a working control board which is fully programmed. The primary remaining task is assembly and refinement of the design. While this is made as a simple statement, this is expected to require a significant amount of work. I expect this will require a major push and long nights.

Project development¶

To reveal the current state, I will answer each of the listed questions individually, as that will best address

What will it do?

My final project is a card dealer, which will distribute playing cards based on a user interface to select the number of players and the number of cards per player.

Who has done what beforehand?

There are a variety of online examples which have made automatic card dealers.

Arduino Card Dealer A card dealder relying on an Arduino as the core microprocessor. As designed, it lacks any interface to change the number of players or cards.
Automatic Card Dealer This card dealer and shuffler was created in a class project. This design is somewhat analogous to my stated design. Adding a shuffler would be an additional spiral to my current work.
Cardboard Card Dealer This is a fun online design with the project made from card board. It doesn’t have any microprocessor, though uses some interesting mechanics to deal the cards from a running DC motor.
Lego card dealer. Built from Lego blocks, this is a functional dealer. It inspires in that it deals cards, but the Lego based design and premade components has little direct applicability to my work.
Joseph Machines Card Dealer. This is a fun version. Joseph Machines is a well known online designer of Rube Goldberg inspired videos. With a motorized toy pickup truck, a wheel, and some string, he is able to deal cards as the truck rotates around a pole. Certainly no functional inspiration for my work, but it is another fun solution to the concept of automatic dealing.

What will you design?

My project requires a number of specific components. The primary ones include:

PCB board to control 2 stepper motors
PCB board to provide 12V power to the stepper motors
A case which holds the PCB and has the dealing mechanism at the top
An internal structure for the case which holds components in place
A turntable which allows the case to rotate
A roller to move the cards
An arm to hold the cards in place and put pressure on the cards against the roller

What material and components will be used?

The case housing will be laser cut MDF
The internal structure will be 3D printed using PLA
The turntable will be based on a lazy susan mechanism
The microprocessor will be a Seeed Studio Xiao RP2040
A PCB will be cut from a copper board
An RP2040 will control the dealer
Two A4988 motor control board
Two NEMA stepper motors
Four capacitors to regulate the voltage coming to the motor
A PCB board which will take power from a QC (Qualcomm Quick Charge) power supply and output 12V
The roller will be 3D printed
Rubber bands will be on the outside of the roller
Springs will be used to create pressure for the arm
An 2x16 LCD screen will provide details on player and card selection, including an I2C communication board
Three buttons will control the functionality, one for number of players, one for number of cards, and one to start the dealer
Assorted M4 nuts to hold motors and other components in place
Brass screw mounts to place in 3d printed parts

Where will they come from?

The MDF and PLA are supplies available in the lab
The microprocessor came from Seeed Studio
The A4988 control boards are available in our lab
The turn table plate is recycled from a used furniture store, though new ones are available at craft shops
The elements for the PCBs (capacitors, LEDs, resitors, potentiometers) are available in our lab
Springs were available in supplies in the lab
Rubber bands were purchased at an office supply store
The LCD screen and I2C board were available in lab supplies
Bolts are available as part of a kit in the lab
Stepper motors are available in the lab

How much will they cost?

At the moment, the vast majority of components used for the project were obtained via supplies in the lab, and consequently I am unaware of any retail cost. For the bill of materials in the final project, cost details will be added.

What parts and systems will be made?

Parts to be made: * 2x PCBs (main control board, and power delivery) * Main case, laser cut * Support frame, 3d printed * Roller * Swivel mechanism

Systems to be made: * Programming main control software * Programming library to control LCD * Programming library to control motor * Programming library to respond to buttons

What processes will be used?

Laser cutting
3D printing
PCB milling
Soldering
CAD design

What questions need to be answered?

The primary questions remaining to be answered related to motor control and working properly for the desired functionality. I already have software functionality that controls two stepper motors, responds to buttons, and interfaces with the LCD.

However, the motors have not been extensively tested for card distribution. Initial testing has resulted in the roller moving the entire deck of cards forward. There needs to be a way to hold back to a single card. A slot for ejecting cards needs to be tested, as that could be a solution to limit to a single card.

Additionally, the mechanism to rotate the dealer case has not be fully tested. I have developed two different rotating mechanisms. One is based on a 3d printed lazy susan (with 3d printed conical bearings). The other relies up on a metalic piece for rotation with stainless steel bearings.

How will it be evaluated?

The evaluation will be based on ability to distribute cards according to the settings. In theory, the software allows up to 6 players, and up to 13 cards/per player. An initial test would be based on ability to distribute 2 cards to 2 players.

Further tests would increase the number of cards and number of players. Success would be defined when the correct number of cards is distributed, and that the cards for each player are separated from other players.

What tasks have been completed?

The PCB boards are completed, as the power board delivers 12V, and the main control board moves motors. The board responds to the buttons, stores the number of players, and the LCD interface is programmed.

In controlling motors, one motor already moves to positions for each player, and another does rotations for the roller.

There has been some initial testing of the card roller mechanism, as well as testing of the pressure arm mechanism.

What tasks remain?

The main remaining task is determining a robust card distibution mechanism. While there is a basic project box designed, it needs futher polish and assembly into a finished looking project.

While these can be expressed in “simple” languaged, pulling it all together is expected to take a large amount of time. I have worked via many prototypes, largely with 3D prints. Since many of the prints are complicated, many of the prints take 2-4 hours. This results in a very extended time line.

What has worked? What hasn’t?

The PCBs and control software has all worked very well.

Find a way to release a single card with the rotor has not worked well. The current primary focus is to determine and discover a robust way to release one card at a time

What questions need to be resolved?

As noted, the primary question to resolve is a need for a robust single card distribution mechanims.

The rotating mechanism is not fully implemented, and needs to be tested.

While the main housing is box shaped, the final size and design of the internal components is yet to be completed.

What will happen when?

I am up against a tight deadline, with approximately two week before my final presenattion. In the first of these two weeks, focus will be on the card distribution. The roller mechanism needs to be refined, as well as finalizing the rotating mechanism.

What have you learned?

This is a very open ended question. My biggest lesson has been synthesizing all the lessons and tasks from the proceeding weeks. Looking backwards, tasks which I previously found intimidating are not a concern at all. Particularly, the ability to design and fabricate a PCB is quick. Similarly, the need to work something up as CAD drawing, and then pushing it for 3D printing (or laser cutting) is quick.

While I have learned a little on pulling all these various skills together, I feel I still need to improve planning. Notably, further upstream testing of things like the roller mechanism could have increased efficiency in the final push.