Key Takeaways
✓ Load cells in UAV scales enable real-time payload monitoring, overload protection, and precise material dispensing for agricultural and logistics drones.
✓ Micro load cells like GML670 (5–200 kg, full-bridge, manganese steel) are ideal for medium-to-large agricultural UAVs, while GML611 (1–50 kg, aluminum alloy) suits lighter payload drones.
✓ Key selection criteria include compact size, lightweight design, vibration resistance, fast response time, and temperature stability.
✓ Proper installation at the drone's payload mounting point and signal conditioning via amplifier modules are critical for accurate weight measurement in flight.
How UAV Scales and Aircraft Scales Are Transforming Agriculture and Logistics
As UAV (unmanned aerial vehicle) technology advances, drones and unmanned aircraft are becoming indispensable tools in agriculture and logistics. UAV scales and aircraft scales — equipped with precision load cells — play a crucial role in improving operational efficiency, safety, and cost-effectiveness.
In agriculture, UAVs are used for pesticide spraying, fertilizer application, seed sowing, and feed spreading. These drones can adapt to complex terrains, operate efficiently in hard-to-reach areas, and significantly improve crop yields while reducing labor costs. Onboard load cells enable real-time monitoring of payload weight, ensuring that the drone carries the optimal amount of material and can return for refilling before running empty.
In logistics, UAVs enhance delivery efficiency, adapt to difficult terrains, protect workers' safety in hazardous environments, and cut last-mile delivery costs. Load cells help verify package weight at pickup, monitor cargo status during flight, and trigger alerts if loads shift unexpectedly — all critical for safe autonomous operations.
Why Load Cells Are Essential for UAV Operations
UAV scales and aircraft scales need load cells to perform several critical functions:
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Payload measurement: Accurately measure seeding amounts, pesticide volume, or cargo weight before and during flight.
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Residual material monitoring: Track remaining pesticide or fertilizer in real time so the drone can return for refilling at the optimal moment — avoiding mid-field empty tanks.
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Overload protection: Prevent exceeding maximum takeoff weight (MTOW), which could compromise flight stability and safety.
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Flight control integration: Weight data feeds into the flight controller to adjust motor power, battery consumption estimates, and flight path planning.
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Compliance and logging: Record payload data for regulatory compliance, crop treatment records, and delivery verification.
Choosing a stable, high-accuracy, lightweight load cell is crucial for these applications — the sensor must not add significant weight to the aircraft while delivering reliable measurements under vibration and temperature variations.
How Load Cells Are Revolutionizing UAV Scale Operations
To implement real-time weight monitoring on a UAV, the load cell is installed at the bottom of the drone's payload mounting bracket or integrated into the tank/container support structure. As material is dispensed or cargo is loaded/unloaded, the load cell detects the changing weight and transmits the signal to the drone's onboard controller.
The controller processes the weight signal through an amplifier module (such as the HX711 or a dedicated signal conditioner), converts it to digital data, and executes the next action — such as returning to base when payload drops below a threshold, or alerting the operator if overload is detected.
Signal Processing Workflow
The typical weight measurement chain in a UAV scale system works as follows:
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Strain gauge sensing: The load cell's Wheatstone bridge generates a tiny analog voltage (mV level) proportional to the applied force.
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Signal amplification: An amplifier module (e.g., HX711, 24-bit ADC) boosts the mV signal to a readable digital value.
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Data processing: The flight controller or companion microprocessor converts the digital value to actual weight using calibration parameters.
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Action execution: Based on the weight reading, the system triggers predefined actions — return-to-home, alarm, payload release, or data logging.
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Telemetry transmission: Weight data is sent to the ground station via the drone's telemetry link for real-time monitoring and logging.
Key Technical Requirements for UAV Load Cells
Selecting the right load cell for UAV and aircraft weighing applications requires attention to several critical parameters that differ from industrial or commercial scale applications:
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Requirement
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Why It Matters for UAVs
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Target Spec
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Compact Size
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Drones have limited internal space; sensor must fit within the airframe without adding bulk
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≤ 40 × 40 mm footprint
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Lightweight
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Every gram affects flight time and payload capacity; sensor weight should be negligible
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< 50 g per sensor
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Vibration Resistance
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Rotors and motors generate continuous vibration; sensor must maintain accuracy under dynamic conditions
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Full-bridge design with mechanical damping
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Fast Response Time
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Real-time monitoring during flight requires rapid weight updates (≥ 10 Hz sampling)
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< 10 ms response, ≥ 80 SPS
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Temperature Stability
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Drones operate in outdoor environments with wide temperature swings; zero-point drift must be minimized
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≤ 0.05% F.S. accuracy across −10 to 60 °C
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Low Power Consumption
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Battery life is critical for UAVs; sensor and amplifier should draw minimal current
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Excitation ≤ 5 V DC, < 20 mA
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Full-Bridge Configuration
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Full-bridge sensors offer better temperature compensation and higher output signal than half-bridge types
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350–1000 Ω bridge resistance
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Recommended Load Cells for UAV Scales
Based on the payload capacity and size of different UAV types, we recommend two micro load cell models — GML670 for medium-to-large agricultural drones (5–200 kg), and GML611 for smaller UAVs and precision applications (1–50 kg).
Model Selection Guide
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Parameter
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GML670
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GML611
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Type
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Micro load cell (full bridge)
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Micro load cell (full bridge)
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Material
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Manganese steel
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Aluminum alloy
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Capacity Range
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5 – 200 kg
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1 – 50 kg
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Dimensions
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34 × 34 mm (thickness 1.0–4.0 mm)
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Compact micro size
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Accuracy
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0.05% F.S.
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0.05% F.S.
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Sensitivity
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1.0 – 2.3 mV/V (range-dependent)
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1.0 ± 0.15 mV/V
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Bridge Resistance
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1000 Ω
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350 Ω
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Best Suited For
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Agricultural spraying drones, heavy-lift logistics UAVs, large aircraft scales
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Small inspection drones, precision payload monitoring, light cargo delivery
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Product 1: GML670 — Micro Load Cell (Full Bridge, Manganese Steel)
The GML670 is a full-bridge micro load cell made of manganese steel, designed for applications requiring compact size, high accuracy, and easy installation. Its 34 × 34 mm footprint and thin profile (1.0–4.0 mm depending on capacity) make it ideal for integration into UAV payload mounting structures where space is at a premium.
The full-bridge configuration provides built-in temperature compensation and higher signal output compared to half-bridge designs, ensuring stable readings even as the drone moves between sunlit fields and shaded areas. With capacities from 5 kg to 200 kg, it covers the payload range of most agricultural spraying drones and medium logistics UAVs.
→ View GML670 Product Details
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Range (kg)
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5
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10
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30
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50
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75
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100
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150
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200
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H (mm)
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1.0
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1.5
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2.0
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2.5
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3.0
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3.0
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4.0
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4.0
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Model
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Range
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Dimension (mm)
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Accuracy
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Sensitivity
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Zero Output
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Resistance
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GML670
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5 kg
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34×34×1.0
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0.05% F.S
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1.0±0.15 mV/V
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±0.3 mV/V
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1000 Ω
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10 kg
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34×34×1.5
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0.05% F.S
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1.0±0.15 mV/V
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±0.3 mV/V
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1000 Ω
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30 kg
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34×34×2.0
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0.05% F.S
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1.6±0.15 mV/V
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±0.3 mV/V
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1000 Ω
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50 kg
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34×34×2.5
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0.05% F.S
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1.75±0.15 mV/V
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±0.3 mV/V
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1000 Ω
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75 kg
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34×34×3.0
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0.05% F.S
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1.75±0.15 mV/V
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±0.3 mV/V
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1000 Ω
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100 kg
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34×34×3.0
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0.05% F.S
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2.3±0.15 mV/V
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±0.3 mV/V
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1000 Ω
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150 kg
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34×34×4.0
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0.05% F.S
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1.5±0.15 mV/V
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±0.3 mV/V
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1000 Ω
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200 kg
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34×34×4.0
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0.05% F.S
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2.0±0.15 mV/V
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±0.3 mV/V
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1000 Ω
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Note: Sensitivity values represent the output of a single sensor at full range. When multiple full-bridge sensors are used in parallel, the total sensitivity equals the single sensor sensitivity. Total range = single range × number of sensors.
Product 2: GML611 — Micro Load Cell (Full Bridge, Aluminum Alloy)
The GML611 is a compact full-bridge micro load cell made of aluminum alloy, offering a capacity range of 1–50 kg. Its lightweight construction (aluminum is significantly lighter than steel) makes it particularly well-suited for small UAVs where every gram matters — such as inspection drones, surveying aircraft, and light cargo delivery drones.
With 0.05% F.S. accuracy and a 350 Ω bridge resistance, the GML611 delivers reliable performance for precision payload monitoring. Its aluminum alloy construction also provides excellent corrosion resistance for outdoor UAV operations exposed to pesticides, fertilizers, and humid environments.
→ View GML611 Product Details
Installation and Wiring Guide
Proper installation is critical for accurate weight measurement in UAV applications. Follow these guidelines for best results:
Installation Steps
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Mounting location: Install the load cell between the payload tank/container and the drone frame, at the structural point where the payload weight is transferred to the airframe.
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Surface preparation: Ensure both mounting surfaces are flat and clean. Use the provided mounting holes — do not drill additional holes, as this can affect calibration.
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Fastening: Use M3 or M4 bolts (depending on model) with spring washers to prevent loosening from vibration. Apply thread-locking adhesive for additional security.
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Cable routing: Route the sensor cable away from motor wires and ESCs to minimize electromagnetic interference. Use shielded cable extensions if needed.
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Amplifier connection: Connect the load cell to an HX711 or similar amplifier module. Standard wiring: E+ (excitation+), E- (excitation-), S+ (signal+), S- (signal-).
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Calibration: After installation, perform a two-point calibration with known weights (zero + full-scale) to establish accurate readings. Recalibrate after any mechanical changes.
Wiring Reference (4-Wire Full Bridge)
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Wire Color
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Function
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Amplifier Pin
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Red
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Excitation+ (E+)
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E+
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Black
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Excitation− (E−)
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E−
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Green
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Signal+ (S+)
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A+
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White
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Signal− (S−)
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A−
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Note: Wire colors may vary by production batch. Always verify polarity with the product datasheet before connecting.
Application Scenarios by UAV Type
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UAV Type
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Typical Payload
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Recommended Model
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Key Application
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Small agricultural drone
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5–20 kg
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GML670 (5–20 kg) / GML611 (5–20 kg)
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Pesticide spraying, seed sowing
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Medium agricultural drone
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20–50 kg
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GML670 (30–50 kg)
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Fertilizer spreading, feed distribution
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Heavy-lift agricultural drone
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50–200 kg
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GML670 (75–200 kg)
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Large-area crop treatment, bulk material transport
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Logistics delivery drone
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1–10 kg
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GML611 (1–10 kg)
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Package weight verification, cargo monitoring
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Inspection/surveying drone
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1–5 kg
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GML611 (1–5 kg)
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Sensor payload weight monitoring
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Large cargo aircraft
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100–200 kg
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GML670 (150–200 kg, multi-sensor)
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Heavy cargo transport, overload protection
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Frequently Asked Questions
Q1: Can I use multiple load cells on one UAV for better accuracy?
Yes. Multiple full-bridge load cells can be connected in parallel to increase the total measurable capacity. When using N sensors in parallel, the total range equals single sensor range × N, while the total sensitivity remains the same as a single sensor. This is useful for large UAVs with multiple payload mounting points — for example, using four GML670 sensors (one at each corner of the payload tray) to measure up to 800 kg with improved load distribution accuracy.
Q2: How do I handle vibration interference in UAV weight measurements?
Vibration from rotors and motors is the primary source of measurement noise in UAV scales. To mitigate it: (1) use full-bridge sensors like the GML670/GML611, which offer better common-mode noise rejection; (2) install mechanical vibration dampers (rubber mounts) between the sensor and airframe; (3) apply digital filtering (moving average or Kalman filter) in the software to smooth readings; and (4) sample at a high rate (≥ 80 SPS) and average multiple readings for each reported weight value.
Q3: What amplifier module should I use with these load cells?
The HX711 is the most commonly used amplifier for UAV load cell applications due to its 24-bit ADC resolution, low power consumption (< 1.5 mA), and compatibility with 5 V microcontrollers. For higher performance, dedicated signal conditioner modules with built-in temperature compensation and digital output (RS485/UART) are available. GALOCE also offers matching amplifier modules optimized for our load cells.
Q4: What is the difference between GML670 (manganese steel) and GML611 (aluminum alloy)?
The key differences are: Material weight — aluminum alloy (GML611) is significantly lighter, making it preferable for weight-sensitive small UAVs; Capacity range — manganese steel (GML670) handles up to 200 kg, while aluminum (GML611) maxes out at 50 kg; Bridge resistance — GML670 uses 1000 Ω (lower power draw), GML611 uses 350 Ω (higher signal output); Corrosion resistance — aluminum offers better resistance to pesticides and fertilizers. Choose GML670 for heavy-lift agricultural drones and GML611 for lightweight logistics and inspection UAVs.
Q5: How often should I recalibrate the load cell on my drone?
We recommend recalibration every 3–6 months for frequently operated UAVs, or whenever you notice weight readings drifting. Always recalibrate after any hard landing, mechanical repair, or component replacement. The calibration process takes about 5 minutes: place the drone on a level surface, tare with no payload, then apply a known reference weight and set the scale factor in the software.
Ready to Equip Your UAV with Precision Weighing?
Whether you're building agricultural spraying drones, logistics delivery UAVs, or industrial inspection aircraft, GALOCE's micro load cells deliver the accuracy, reliability, and compact form factor your application demands. Contact our engineering team for product selection guidance, custom calibration, and volume pricing.
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