Wooden Disc Player
Introduction: Wooden Disc Player
I wanted to demonstrate how information storing devices work by building a large scale disc playing machine. Instead of being based on light interference like CD players, the device I built plays wooden discs with holes and "non-holes" (as I refer to them in this instructable) that either pass or block a laser beam. These holes and non-holes correspond to 1's and 0's in binary data that code a text message, like song lyrics or a quote. The binary information is read off the disc, stored on an Arduino, and decoded to display the text message on an LED matrix on the front of the device. As the data is being read, the LED matrix is populated to visualize the binary information. When a high bit is read, a MIDI note is also played. The music produced may sound random, but it symbolizes a series of 1's and 0's that actually holds meaningful information.
The wooden disc player I created can only hold about 700bits (<0.1kB) because of how large the holes are in the disc. Therefore, the messages that can be stored are short. For reference, a CD can hold around 700MB of information, which is about 10 million times more information than the wooden discs I made. 1014
The whole project helps imagine the scale of information storage on CDs (an already dated storage device) and how the digital information is read and decoded into something meaningful to humans.
In this instructable, I will go over the system design and construction, how the message was converted to binary information on a wooden disc, and the many challenges along the way.
The project was inspired by many sources, including:
* 8-bit Show and Tell's channel had an awesome video about a secret message stored on a record that could be read on a Commodore 64
* Vertical record players, like those by Gramovox and <PERSON>
* Mechanical music playing devices called polyphons, developed in the mid 1800's
* The Computer History Museum in Mountain View, CA
* Techmoan's video on the CED Videodisc developed by RCA
* Applied Science images records, CDs, and DVDs with electron microscope
* Optical rotary encoders
Supplies
10X 10”x15”x1/8” plywood sheet
White acrylic sheet
1X 50RPM DC motor
1X Arduino Nano
1X H-bridge L9110 https://www.amazon.com/gp/product/B00NN6EB3U/ref=...
1X stepper motors Nema 17 Bipolar step motor (3.5V 1A)
1X 2mm lead screws
2X pillow blocks 21. Two lead screw nuts 22. Two bearing slide bushing and 200mm linear shafts: https://www.amazon.com/gp/product/B01KL7I65W/ref=...
1X DOT matrix display MAX 7219
1X 5V power supply
1X Mini USB cable
2X photodiodes - https://www.amazon.com/gp/product/B00M1PMHO4/ref=...
2X IR LEDs
1X IR photodiode
2X 650nm laser module
1X 5.5 x 2.5 mm Panel Mounting DC Power Jack https://www.amazon.com/gp/product/B01LQGESUO/ref=p...
1X power switch - https://www.digikey.com/product-detail/en/zf-elect...
1X MIDI jack - https://www.amazon.com/gp/product/B01GBT9RC0/ref=p...
3X LM358 op amp https://www.digikey.com/en/product-highlight/t/tex...
2X NPN transistors
1X TIP120 transistor
2X diodes
3X 10k trim pots
Resistors as shown on system schematic
Prototype board
8mm diameter magnets - https://www.amazon.com/gp/product/B07DD61G2F/ref=p...
Metric hardware kit
Step 1: System Overview
The purpose of the device is to decode a message stored on a wooden disc. In this step, I'll provide a quick overview of the entire process.
1. Pick a message. I chose messages from some of my favorite writers and musicians to store on the disc. In the example drawing above, I have the classic "don't panic!" from Hitchhiker's Guide to the Galaxy.
2. Create a binary conversion table. If you are unfamiliar with binary information, there are loads of useful books, courses, and videos for learning all about the process. 33