Team C8: Domo Arigato Poker Roboto
Carnegie Mellon ECE Capstone, Spring 2019: Mark McKinzie, Chris Reed and Eric Sun
Last week I did some light research and work to prepare to write the motor driver, but other than that was unproductive.
I believe I’m still on track for my tasks. Next week I will work on the communication layer between the play areas and the central computer, as well as the motor driver.
No changes were made to the design this week. No changes to the schedule have occured. As we’ve discussed in past team status reports we believe the shuffler/dealer is still the riskiest part of the project, but nothing has changed to make us think we need to starting working more seriously on contingency plans.
As Chris and Mark get farther along on printing the parts for the shuffler/dealer and setting up the servo motors, we feel more and more confident that it will be completed on time and within spec.
Last week I finished the chip detection driver, and worked on a rough prototype of the e-ink display driver. With the display driver I ran into some difficulty because there are very subtle differences between the models that are not made explicit in the documentation. It was a process of trial and error to get the screen to work, but once it began working it was an easier process to get the rest of the driver figured out.
I ended up using a second library to make generating images for the screen easier. The way an image is sent to the device is as a big two dimensional array of binary values, because each pixel the screen can either be on or off. However to generate text and graphics by hand would be a pain and require a large amount of boilerplate code. Instead I use a two step process. The first step is generating the image using PIL (Python Image Library). It creates a “canvas” that can then be drawn on. It has resources for drawing text, images, shapes, and more. Then the second step is to take that canvas and render it to black and white, and output an array like the one required by the screen. That data is then written to the screen’s memory.
Finally, I wrote some simple code to glue everything together for the demo. It was a simple loop that checks for new cards, checks for new chips, then updates the screen with the results if any are new. While this isn’t the exact approach that will be used for the final game coordinator running in the play area, I hope to be able to reuse a lot of the code.
I believe I’m still on track for my tasks. Next week I will work on finalizing the game coordinator in the play area and building a simple server to test with on the central computer.
This week I fabricated poker chips for each dollar value: $5, $10, $15 using copper tape rather than aluminum foil as a conductive medium. This method of construction was much simpler and much easier as the copper tape adheres to the poker chips and the leads of the resistors, minimizing the need for excessive solder to hold the resistor in place. In addition the dealer tray which will rotate was fabricated in the Makerspace using a 3D printer and holds a full deck and is slick enough that dealing one card at a time from the bottom of the deck is a simple and fast process.
The next step is to test stacks of the copper taped chips and see if the dollar values remain accurate. For the shuffler and dealer we need to print the shuffler trays and then begin assembling the motor and gear system inside the 3D printed system. The schedule is still on track to be completed on time.
Our demo went very well this week. All of the aspects of our player area are functional and ready to go: We have a full deck of RFID cards that can be detected correctly by our RFID reader, we have a prototype chip with embedded resistor and are able to detect the monetary value of a stack of chips, and we have our E-Ink display hooked up so that it displays the cards and chips of the player in real time.
We have also begun production on our shuffler/dealer, as stated in Chris’ weekly update. We will also begin on working on the central computing unit, so that we can link multiple play areas together now that we have one functioning set. We will continue to work out that before working on incorporating the play area into a more visually pleasing unit.
This week I focused on 3D printing parts for our shuffler and dealer. I made modifications to lower the cost of the parts we wanted to print. I was able to get the first one-sixth dealer tray model printed out as well as the dealing platform to hold the deck of cards. Both pieces came out very sturdy, but since we made them very thin the diagonal slope on the dealing tray is a little flimsy so we may support it with a little tape on the back to ensure it doesn’t snap. For the next dealer tray we print, if we have more money, I may make it a little thicker to try and solve this issue.
We are on schedule for our project right now. Next week, I want to print the shuffling platforms and work with Mark to hook up our motors to both the shuffling and dealing platforms so we can practice dealing and shuffling the cards out. Once we know the mechanics work, we can work on putting them all together into one enclosure as a unit.
