Tic Tac Toe Machine

The team

This week’s objectives

• Mechanical Design
  • design a machine that includes mechanism+actuation+automation+application ✅
  • build the mechanical parts and operate it manually ✅
• Machine Design
  • actuate and automate your machine ✅
• Document the group project and your individual contribution (this page!) ✅

Machine

Application

Application a device designed to help the user to perform specific tasks

The application for our machine is to play tic-tac-toe against a human adversary, using an aggressive play-to-win AI.

Automation

Automation describes a wide range of technologies that reduce human intervention in processes.

Our machine provides full end-to-end automation for the entire game of tic-tac-toe.

Actuation

Actuation. An actuator is a component of a machine that is responsible for moving and controlling a mechanism or system, for example by opening a valve. In simple terms, it is a “mover”.

From the point of view of machine design, Actuators are the parts of the machine that operate in its environments ( to affect it/change it, in some way), while the sensors are the parts that receive information from its environment.

In terms of actuation, our machine has a moving pen, whose tip can be arbitrarily positioned in any position in the operating space/volume.

For all intents and purposes, however the pen will only occupy 2 planes in space:

• the paper plane: when the tip of the pen is touching the surface below the machine. This setting can be used to paint, draw on it or mark it in some way.
• the hover plane: when the tip of the pen is held away from the floor/paper/whiteboard. This position allows us to freely move the pen without leaving marks or painting anything.

Mechanism

Mechanism (engineering), rigid bodies connected by joints in order to accomplish a desired force and/or motion transmission

The machine that we have built has various mechanisms to operate and perform action in all 3 spacial dimensions:

• 1 mechanism to operate on the X axis (1 degree of freedom) using dual stepper motors
• 1 mechanism to operate on the Y axis (1 degree of freedom) using a single stepper motor
• 1 mechanism to operate on the Z axis (1 degree of freedom) using a single servo motor

The combination of these mechanisms allow the machine to have an operating space/volume of approx:

412 mm x 420 mm x 18 mm = 3,114,720 mm³ = 3114 cm³

Here’s a short excerpt of the code used to control the machine over the operating space.

This week’s responsibilities

• Angel:
  • TO DO
• Marco:
  • TO DO
• Dhanu:

Mechanical Design and assembly We started out with an already existing frame made with aluminium and had to add, - X AXIS: 2 acrylic plates as holders for 2 steppers working in unison. - Holders laser cut in 5mm acrylic sheet to hold the stepper motor, wheels and a provision for endstoppers. - Y AXIS: Aluminium frame attached to the 2 X axis acrylic plates and an extension for the Z axis. - Z AXIS: A stationary plate extension and a Servo motor with a pen attached to it.

• Edu:
  • Software Development
    • Backend implementation
    • Frontend design
    • Analysis and evaluation of tic-tac-toe algorithms
    • Integration of existing algorithms into the backend code
    • Parametrization and configuration of the application
  • GCODE:
    • Development
    • Validation (in GCode Simulators)
    • integration of GCode into backend
  • Communications
    • Implementation of Serial comms between backend app and Arduino/GRBL

Problems encountered

During mechanical design and assembly

We started out with an already existing frame made with aluminium but,

• We had to use an aluminium frame that somehow had to be connected to the 2 acrylic holder plates, as the Y axis.
• We needed to move the pen up and down without the addition of an extra axis/motor.
• The initial iteration of the assembly had the pen too far away from the bed and adding a plate as an extension made it flimsy.
• We needed a stable and reliable bed at the base for a lot of testing.

During electronics design and implementation

TO DO

During software programming

The software development part ended up being a demanding beast, and we encountered several issues as the days went by:

• We had issues with GRBL and the use of Relative coordinates (but that turned out to be a ghost, and GRBL actually worked perfectly)
• We accidentally burned one arduino board, and we still don’t know how
• We almost got our computers infected with a virus while trying to find a fix for a Serial communications library
• And we had serious issues while trying to get Serial communications working because we forgot to add 1 critical byte at the end of the commands.

If you want to read about all the issues that we encountered during the software development/programming, check out Edu’s page

Development Iterations

Iteration 1

Sending custom commands to arduino via Serial Interface

Iteration 2 - The product, as we presented it

Sending GCODE commands to Arduino with GRBL installed

Iterations with the assembly

Iteration 1

The first iteration of the assembly had the Y axis above the base frame and we were planning to make an extension arm as the Z axis. Eventually, we realised that flipped it upside down would make the Z axis shorter and makes the machine more stable.

Iteration 2