When I was a student I use to play chess with my flatmates. Then I moved in with my wife and I teach her how to play chess, but she doesn't like it a lot. So I start building a robot in order to play chess with me. The project isn't completed yet but... I will.
I'm part of a robotics association (I-Grebot) and we have the chance to own an ultimaker1. So I decided to use it a lot for this project.
Step 1: Find Chess Pieces
First things first, I need chess pieces. I find a very nice model on thingiverse.
Step 2: Piece Recognition
Ok I find my chess pieces, how my robot is going to recognize them on the chessboard. There are plenty of internet projects with shapes recognition thanks to a webcam. But I want something different and I want a little of magic. If a web cam is standing over the chess board, people will quickly guess that it helps the robot to know what piece were moved. I want something more discrete, so people say, "How does it work?".
I decide to hide RFID chips inside each pieces and use a reader under the chessboard squares.
Step 3: Download FeeCAD
In order to hide the RFID chip, we have to modify the pieces model to draw a cavity inside. I tried to import my STL files into Solidworks but that said "impossible to import the piece has too many side". So I have to use FreeCAD to simplify the model before importation.
Step 4: Simplify Each Piece
- Import your piece in FreeCAD, and select the mesh in the left pannel
- Go to "View" menu and select Workbench->Part (A new menu appear in the top pannel)
- Go to "Part" menu and select "create form from mesh" the enter 1.0 (it can freeze for a minute or two)
- A new part in blue appeared in the left pannel.
- Delete the old mesh and keep the part.
- Export your part in *.STP.
Step 5: Modify Your Piece
I am more comfortable with solidworks so I will use it to modify each piece. My RFID chips are small discs of 18mm diameter and 1mm thick. So I will make a cavity of 20mm diameter and 2mm thick in order to be sure. The cavity have to be blind, I select the base of the piece and make a hole of about 5mm, then I make an extrusion of 3mm, it leave the cavity needed of 2mm at about half the base of the piece.
Step 6: Print Your Pieces
I use Cura to slice my part and build the Gcode. I use the plugin "pause at height" to let me put my chips inside the base.
Step 7: Choose Technique to Move the Pieces
On internet you can find similar projects in which the chess pieces are moved by a robotic arm such as this one. Obviously this is not the choice I made for the movement of pieces on the chessboard. Always with the objective to put a little magic in the project, I chose to use the arm of Inmoov project.
For those who do not know the Inmoov project, it is the first life size humanoid robot you can 3D print and animate. The project was designed by Gael Langevin, a French modelmaker and sculptor. Replicable on any home 3D printer with a 12x12x12cm area, it is conceived as a development platform for Universities, Laboratories, Hobbyist, but first of all for Makers.