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Overview
Our project converts mechanical energy into electricity to power an analog record player.
Keywords: Energy, Circuitry, Music, Fabrication
Process
We inspected inside the record player to realize it was powered by simple analog circuits. It requires 12V. Cranking the stepper motor can generate this, but we needed capacitors to store energy so the player continues briefly after motion stops.
We tested with an LED to confirm capacitor behavior—if working, the LED should stay on briefly after stopping.
Problem: Not enough continuous energy to charge the capacitor sufficiently.
Question: How do we preserve the work done?
Solution: Use rotational energy + gears to spin the stepper motor more, producing more voltage.
Prototyping Gears
Got it working smoothly to light up LED, charge the capacitor up enough for smooth discharge
Playtesting
We tested with a Beatles record. With consistent cranking, the record played (though uneven—like a DJ remix without steady motion).
VID_20260227_134855.mp4Calculations & Energy Storage
Known:
12V, up to 1A
~0.5A draw, 15W max
Capacitance needed for 1 min:
~3 Farads → too large
Current capacity (4700 µF):
~0.042 seconds → not enough
Conclusion:
Capacitors mainly smooth voltage; most energy comes from real-time cranking.
Learnings
Measure stepper motor output (OCV, SCC)
Ensure voltage >12V and current >0.5A
Calculate energy early:
P = VI → 6W
E = PT → 30J (for 5s)
Capacitor energy = ½CV²
Interesting Observation
We observed ~2 seconds of music after stopping, which doesn’t match calculations.
Discharge/Recitifer Circuit:
View Final Documenation
View Final Documenation
PXL_20260302_195013273.mp4538A6811.MP4Process for Future Self
Determine electrical requirements (V, I, power, energy).
Calculate required capacitance.
Measure generator output (OCV, SCC).
Design energy conversion mechanism.
Optimize energy transfer efficiency.
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