⚙️ Samson eFit Module – Internal README (MVP Implementation)

🎯 Purpose

Build a compact, motor-controlled resistance unit with basic wireless control and encoder-based feedback.
Stay within MVP scope and avoid feature creep until core functionality works.

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🧭 MVP Core Goals

• Smooth electronic resistance using BLDC + driver
• Wireless control of load (ESP32 → PWM)
• Encoder-based feedback to maintain commanded resistance
• Basic safety limits (current/thermal)
• Minimal UI (phone/Pi/serial)

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📦 Current Components (Received)

#	Component	Purpose	Notes
1	Waveshare 4" Round DSI Touch Display	UI	Use later; not MVP-critical
2	AS5600 Magnetic Encoders (5 pcs)	Angle/rep sensing	High priority for control loop
3	Milwaukee M18 Battery Adapters (2 pcs)	Power source	Portable demos; regulate as needed
4	400W BLDC Motor Controllers (2 pcs)	Motor driving	PWM control with FWD/REV/Brake

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🧩 High-Level Architecture (MVP)

• ESP32: PWM output + encoder reading + wireless interface
• BLDC Driver: Drives motor phases based on PWM
• AS5600 Encoder: Shaft position/velocity feedback over I²C
• Power: 18V battery via adapter (regulate for ESP32)
• UI: Minimal (phone > Pi display for later)

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🛠️ Implementation Order (Milestones)

1. Bench-test BLDC controller + motor (no load)
2. Read encoder position/velocity reliably
3. Close feedback loop (PWM adjusted from encoder)
4. Add safety limits (brake/stop/overcurrent handling)
5. Wireless interface to set target resistance
6. Optional: Pi display UI after stable MVP

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💻 Firmware Tasks (ESP32)

• PWM generation + tuning
• Encoder I²C driver (AS5600)
• Resistance control loop (angle/speed → PWM adjust)
• Safety watchdogs (fault detection)
• Simple wireless command interface

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🔩 Hardware Tasks

• Encoder magnet mounting on pulley/shaft
• Secure motor + driver on bench fixture
• Power routing + regulation
• Fusing + emergency stop provisions

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🔋 Power Notes

• M18 battery: 18V nominal
• Driver acceptable: 6–60V
• ESP32 requires regulated 5V/3.3V
• Add DC-DC regulator if powering both from same source

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🚫 Scope Limiters (Avoid Feature Creep)

Not MVP:

• Full AI workout planning
• Cloud accounts or server database
• Advanced touchscreen interface
• Subscription model

MVP success = controllable electronic resistance + encoder feedback loop.

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🧪 Testing Targets

• Commanded resistance holds within stable margin
• Encoder data noise acceptable
• No uncontrolled torque spikes
• Safe stop behavior verified

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📝 Notes to Ourselves

If it does not directly help us control and stabilize resistance, it waits until after MVP.