Item specifics
Description
SC7A20H Product Overview
The SC7A20H is a high-performance, low-power 3-axis linear accelerometer module designed for motion detection, tilt measurement, and vibration analysis in consumer electronics, IoT, and industrial monitoring. The full-scale range is user-programmable across ±2g, ±4g, ±8g, and ±16g, and both I2C and SPI digital interfaces are supported for direct connection to mainstream MCUs like Arduino, ESP32, and STM32. A built-in 16-bit high-resolution ADC, 32-level FIFO buffer, and configurable motion-detection interrupts enable real-time event recognition—including tap, free-fall, and activity/inactivity—even in ultra-low-power modes. Operating from 1.7 V to 3.6 V in a compact module form factor, the SC7A20H is ideal for wearables, game controllers, drone attitude sensing, and industrial self-leveling applications.
SC7A20H Core Features
3-Axis Sensing: Simultaneously measures static gravity and dynamic acceleration on X, Y, and Z axes
Programmable Full-Scale: User-selectable ±2g/±4g/±8g/±16g for high-sensitivity or high-impact scenarios
Dual Digital Interface: I2C (Fast-mode up to 400 kHz) and SPI (up to 10 MHz); on-board address selection pads
High-Resolution Data: 16-bit ΔΣ ADC with typical sensitivity of 1024 LSB/g in ±2g range
Ultra-Low Power: Standby current below 1 µA; measurement-mode current as low as 10 µA, perfect for battery-powered devices
FIFO & Interrupts: 32-level FIFO reduces host polling; configurable interrupts for free-fall, tap, and activity/inactivity detection
Wide Supply Voltage: Operates from 1.7 V to 3.6 V, compatible with both 1.8 V and 3.3 V systems
Compact Module Layout: Provides VCC, GND, SCL/SCK, SDA/MOSI/MISO, CS, and INT pins for plug-and-play integration
SC7A20H Applications
Wearables: Smart bands, pedometers, fall detection with all-day activity monitoring
IoT Endpoints: Asset trackers, tilt alarms, smart furniture attitude sensing
Gaming & Remote Controls: Air mice, gamepads, motion-sensing remote controls
Drones & Robotics: Auxiliary attitude estimation, collision detection, vibration monitoring
Industrial Instrumentation: Self-leveling platforms, structural health monitoring, gimbal stabilization
SC7A20H Key Advantages
Flexible Range Configuration: Easily switch full-scale via register writes—no hardware changes—adapting to different motion intensity levels
Dual Interface Compatibility: The same module supports I2C and SPI, allowing flexible connectivity based on MCU pin availability
Extremely Low Power: At low data rates, current consumption is only microamps; combined with FIFO and interrupts, the MCU can sleep extensively, greatly extending battery life
Intelligent Interrupt Engine: Hardware detection of free-fall, tap, and activity changes eliminates continuous polling by the host, reducing system power
Easy Development: Open-source libraries available for Arduino, MicroPython, etc., with abundant reference code for quick prototyping
Robust & Compact: The module includes necessary decoupling and level-compatible circuitry, ready to connect to 3.3 V or 1.8 V systems
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FAQ:
How do I choose between I2C and SPI on the SC7A20H module?
The module supports both interfaces; selection is typically made via the CS pin and on-board solder pads. Use I2C if you're short on MCU pins (only two wires needed, and multiple devices can share the bus). Choose SPI when higher data throughput is required, such as for real-time vibration analysis at up to 10 MHz clock speed. The register maps are virtually identical, so core functionality remains the same.
How do I change the full-scale range? Should I use high sensitivity or a large range?
Write to the control register to switch between ±2g, ±4g, ±8g, and ±16g on the fly. For tilt sensing (e.g., digital level), ±2g provides the highest sensitivity (~1024 LSB/g). For tap or impact detection, ±8g or ±16g prevents signal saturation. Choose the range based on your expected peak acceleration.
How low is the power consumption? How long can a battery-powered device last?
At 1.6–3.6 V, the module draws as little as ~10 µA in low-power mode at 1 Hz ODR and under 1 µA in standby. With FIFO buffering and motion-wake interrupts, the host MCU can sleep most of the time, allowing a coin cell to power a tilt monitor or pedometer for years.
How does the SC7A20H compare to popular accelerometers like the ADXL345 or LIS3DH?
They are functionally equivalent 3-axis digital accelerometers with I2C/SPI, programmable ranges, and interrupt outputs. The register map and initialization sequence differ slightly, but common algorithms (tilt, step counting, tap detection) are fully portable. Only minor driver modifications are needed when migrating code.
How do I handle noise and drift in the acceleration data? Any recommended filter settings?
The on-chip ΔΣ ADC provides inherent noise reduction. On the MCU side, a first-order low-pass filter or moving average can smooth the data. For pedometers or attitude sensing, 25–50 Hz ODR with light averaging works well. For FFT-based vibration analysis, use ≥200 Hz ODR and process raw samples.
What events can the INT pin signal, and how do I configure them?
The INT pin can be configured for free-fall, single/double tap, activity/inactivity, or data-ready interrupts. By setting the appropriate enable registers and thresholds, the pin asserts when an event occurs, allowing the MCU to wake up and respond quickly without continuous polling—greatly reducing system power.
How can I use the FIFO to reduce host MCU intervention? How much data does it hold?
The built-in 32-level FIFO stores the last 32 sets of 3-axis data. When the fill level reaches a programmable watermark (e.g., 24 samples), an interrupt fires, and the MCU reads a complete block at once. This is very efficient for continuous motion recording or periodic wake-up analysis.
How do I convert 3-axis acceleration data into tilt angles?
Use the gravity components on each axis with atan2() to compute pitch and roll. After zero-offset calibration (averaging readings with the module level), the formulas are: Pitch = atan2(-X, sqrt(Y*Y + Z*Z)), Roll = atan2(Y, Z). These give the angles relative to the horizontal plane.
What operating modes does the module have? How do I switch between low-power and high-performance?
Typical modes include normal, low-power, and standby. Normal mode provides high ODR (hundreds of Hz) for fast motion. Low-power mode reduces ODR and current dramatically for slow tilt monitoring. Standby shuts down all but the serial interface, minimizing power draw. Switching is done via the power control register.
Does the module need calibration after power-up? How do I eliminate zero-g bias?
It's recommended to perform a one-time level calibration after installation: place the module horizontally, collect a few hundred samples, and compute the average value for each axis as the offset. Subtract this offset from all subsequent readings to significantly reduce both mounting and sensor bias errors, greatly improving angle accuracy.