Summary of Secret Compartment Chess Set
This article details a DIY project to build a chess set with a secret, magnetically locked drawer. The mechanism uses magnetic reed switches under specific board squares and magnets on the pieces; when correctly arranged, an Arduino triggers a servo to release the spring-loaded drawer. A pushbutton locks it again, accompanied by a buzzer sound.
Parts used in the Secret Compartment Chess Set:
- Arduino Uno
- Standard Servo
- Magnetic Reed Flange Switches (x6)
- Universal 1000mA AC Adapter
- M-type Adaptaplug
- Grid-Style PC Board
- SPST Normally Open Pushbutton
- Piezo Electric Buzzer
- Round Ceramic Magnets (x32)
- 10kOhm Resistors (x7)
- Male header pins (x3)
- Plywood sheets (various sizes)
- Chess Piece Set
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) Arduino uno (RadioShack #276-128)
(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 outer box pattern on the 1/4″ plywood.
Use a laser cutter to cut the drawer pattern on the other sheet of 1/4″ plywood.
Step 3: Glue outer box
Glue together the pieces of the outer box.
Step 4: Glue drawer
Glue together the pieces of the drawer.
Save the 1/2″ squares cut from the same sheet. You will later use these to mount the servo.
For more detail: Secret Compartment Chess Set
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How does the secret drawer unlock?
The drawer unlocks when magnets on chess pieces are placed on specific squares with magnetic switches, causing the Arduino to move a servo lever that releases the spring-loaded drawer. -
Can I lock the drawer manually?
Yes, you can lock the drawer by pressing the side pushbutton while holding the drawer in place. -
What provides the audio feedback for the mechanism?
A 75dB Piezo Electric Buzzer sounds whenever the servo lever is being opened or closed. -
Which component controls the servo movement?
An Arduino Uno programmed to activate the standard servo when the magnetic switches detect the correct piece arrangement. -
How are the chess pieces modified for this project?
Magnets are glued to the bottom of every chess piece to interact with the magnetic switches underneath the board. -
What material is used to construct the box and drawer?
Plywood sheets of various thicknesses (1/4", 1/8", and 1/2") are cut using a laser cutter and glued together. -
How many magnetic switches are required for the project?
Six Magnetic Reed Flange switches are needed and installed underneath the chosen squares on the chessboard.
