Music Player
Date: 2025-06-18
Time Spent: 2.5 hours Task: Research — Understanding How Turntable/Stereo Machines Work
i watch some teardown vids and read around abt how theese stero machines work. took notes fast so its kinda scattered but heres what i got
digital turntable stereo stuff:
- Power: system takes in 12v DC, that’s what feeds the rest (motor/speakers/mcu)
- Motor thing (ESC): tells the brushless motor how fast/strong 2 go, uses PWM
- BLDC motor + gears: spins fast, gears slow it to 33/45rpm.
- platter/disk: the thing u spin manually or auto (scratching too lol)
- sound system: uses rp2 microcontroller + dac, sends music to speakers
- controls: sliders 4 speed & vol, 3 MX buttons, touchscreen too
- microcontrollr: does all the thinking - audio, spinning, buttons, screen
Date: 2025-06-19
Time Spent: 2 hours Task: Research — Motor Control and Audio Processing Integration
looked into the rp2 dual core use 4 audio + motor at the same time. drew out gear system too.
Key Concept
im trying to mix real disk feel w/ digital music, so u can scratch or cue by hand but still play mp3s. rp2 does both jobs together.
Gears i planned
- big gear (4t): on the disk shaft
- smol gear (4t): connected to the motor
- encoder gear (6t): for the feedback
ratio = 1:1 for motor and platter encoder sees 1.5x turns for more accuracy
basic system
music path: file > rp2 audio core > audio hat > speakers
motor path: slider pot > adc > rp2 > pwm > esc > motor > gearz > platter
interface: manual spin > encoder > rp2 > update song spot MX buttons > rp2 > triggers touchscreen > spi/i2c > screen stuff
Date: 2025-06-24
Time Spent: 2 hours Task: Fabrication — Creating Top Cover with Interface Cutouts
made the top panel 4 the case. it holds all the buttons + screen + sliders. looks ok
features
- 3 holes 4 Cherry MX buttons
- long holes for speed/vol sliders
- middle rectangle for the LCD
- cut it from MDF like the rest
- holes 4 mounting screws
protects insides but still lets u use everything
Date: 2025-06-25
Time Spent: 30 minutes Task: Fabrication — Creating Bottom Base Panel
made the base (bottom part) of the case so now it’s like a real box lol
what it has
- solid MDF base
- speaker spots (recessed a bit)
- part that can be opened 4 repairs
- holds stuff in place strong
finishes the shell so now its enclosed
Date: 2025-06-26
Time Spent: 2 hours Task: Wiring and Component Testing
wired all parts + tested on pi zero W (didnt work great so swapped it)
wiring setup
GPIOs used:
- i2s pins > audio hat
- i2c+spi > LCD screen
- buttons > digital pins w/ pullups
- sliders > i2c ADC
- motor > pwm pin
- encoder > 2 input pins (quad signal)
shared buses to save pins
results
on Pi Zero W:
- motor ran fine
- audio lagged bad
- screen was slow
- pi couldn’t do both well
issues:
- audio breaks up
- screen lags = bad UX
- CPU not enough
fix:
- moved to pi zero 2W
- quad core fixed all that
- same shape so easy swap
- everything runs smooth now
Date: 2025-06-27
Time Spent: 4 hours Task: Software Development — Creating Turntable Player Application
wrote a full python app that plays music, spins disk, shows screen stuff, all that.
features
player stuff:
- plays mp3s w/ pygame
- finds music in
/home/pi/Music/ - gets song name, artist, album etc
- shows album art too
- playlist with shuffle
hardware:
- MX buttons do play/pause etc
- sliders read by SPI ADC
- sliders control speed + vol live
- button states managed
screen:
- pygame GUI on LCD
- shows song data
- art shows nice
- has vol/speed indicators
- progress bar too
audio:
- speed change 0.5x to 2x
- vol slider mapped live
- works w/ audio HAT
- BT toggle too
system stuff:
- multithreaded so it don’t lag
- updates at 10hz
- runs at boot with systemd
- shuts down clean
status
software is mostly DONE:
- 4 scripts, ~400 lines
- split into modules
- hardware layer added
- install script done too
NOT tested on real thing yet. need to plug it in & try IRL