I play chess pretty poorly and have always wanted to get better, but I don't even own a chess set. I decided I wanted to make my own set, but with a twist. I have made a chess board with a secret drawer that is locked unless the pieces are arranged on the board in a specific pattern.
The way it works is there are magnetic switches underneath the chosen squares on the chess set and magnets glued to the bottom of every chess piece. When the chess pieces with the magnets are placed on the squares with the magnetic switches, the switches open. The arduino is programmed to move a servo with a lever attached inside of the box when the switches are open. When this lever is lifted, the spring-loaded drawer is no longer held in place and pops out.
To lock the drawer again, press the pushbutton on the side while holding the drawer in. A buzzer will go off whenever the servo lever is being opened or closed.
Step 1: What you need
(x1) Standard Servo (RadioShack #273-766)
(x6) Switch-Magnetic Reed Flange (RadioShack #55050593)
(x1) Universal 1000mA AC Adapter (RadioShack #273-316)
(x1) M-type Adaptaplug (RadioShack #273-344)
(x1) Grid-Style PC board (RadioShack #276-149)
(x1) SPST Normally Open Pushbutton (RadioShack #275-644)
(x1) 75dB Piezo Electric Buzzer (RadioShack #273-793)
(x32) Round Ceramic Magnet (RadioShack #64-1883)
(x7) 10kOhm Resistor (RadioShack #271-1335)
(x3) Male header pins
(x2) 36"x24"x1/4" plywood
(x1) 1.5"x1.5"x1/8" plywood
(x1) 2"x2"x1/2" plywood
(x1) Chess Piece Set
Step 2: Cut wood
Use a laser cutter to cut the drawer pattern on the other sheet of 1/4" plywood.
Step 4: Glue drawer
Save the 1/2" squares cut from the same sheet. You will later use these to mount the servo.