Automated FarmBot Lighting System

This project involved the development of an automated, height-adjustable LED lighting system for the FarmBot Genesis to improve lighting consistency and reduce energy use in controlled-environment agriculture. The system used an ultrasonic sensor to estimate plant canopy height and a motorized winch mechanism to reposition LED fixtures and maintain an optimal light-to-canopy distance. Subsystem testing validated safe mechanical operation, sensor accuracy, reliable homing, and demonstrated an estimated 43% reduction in lighting energy consumption compared to fixed-height systems.

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Drew Geiser

Project Timeline

Jan 2025 - Dec-2025

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Engineered a winch-driven lifting mechanism capable of synchronously repositioning multiple LED fixtures while maintaining alignment and load stability.
Established an empirically derived light-to-canopy operating distance through PPFD testing to inform mechanical sizing and control logic.
Integrated safety features, including limit switches and an electromagnetic brake, to prevent uncontrolled motion of the lighting system.
Conducted structural and performance testing, confirming acceptable shaft deflection under load and repeatable homing behavior.
Quantified energy efficiency gains, showing that dynamic light positioning can substantially reduce power demand relative to static lighting.

SKILLS

Solidworks

Electromechanical System Integration

Motor Selection & Drive Integration

Engineering Calculations (Deflection, Torque, Load Analysis)

External Links

Final Report

Final Poster Presentation

Technical Validation & Design Details

Light Intensity Characterization: Empirical PPFD testing quantified the relationship between LED fixture height and canopy light delivery, identifying an optimal operating distance of approximately 0.35 m used to define lift travel limits and control setpoints.
Canopy Height Sensing: Ultrasonic sensor validation demonstrated a typical measurement error of approximately 24 mm, meeting design tolerances and supporting conservative canopy-responsive positioning at the subsystem level.
Energy Efficiency: Comparative analysis showed that dynamically adjusting light height can reduce lighting energy demand by approximately 43% relative to fixed-height operation, with negligible power draw from the lift mechanism.
Safety & Risk Mitigation: A formal Failure Modes and Effects Analysis (FMEA) informed safety-critical design decisions, including mechanical travel limits, limit switches, and an electromagnetic brake to prevent uncontrolled motion

PPFD_vs_Distance_power_law (1).png

Figure 1: Measured PPFD as a function of LED fixture height, used to determine the optimal light-to-canopy operating distance (~0.35 m).

Figure 2: Section view of the winch-driven lighting lift mechanism integrated above the FarmBot growing bed.

Figure 3: Electronics mounting shelf supporting the stepper motor, motor driver, and Arduino-based control hardware.

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Figure 4: Electronics mounting shelf supporting the stepper motor, motor driver, and power supply.

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