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STM32F4 für Predictive Maintenance mit TensorFlow Lite Micro

The STM32F4 is the workhorse Cortex-M4 for vibration-based predictive maintenance. With 192 KB SRAM, 168 MHz clock, and DSP instructions, it runs TFLite Micro vibration classifiers at under 10ms inference — reliable, affordable, and backed by the largest STM32 ecosystem.

Veröffentlicht 2026-04-01

Hardware-Spezifikationen

Spez. STM32F4
Prozessor ARM Cortex-M4F @ 168 MHz
SRAM 192 KB
Flash 1 MB
Konnektivität USB OTG FS
Preisbereich $3-10 (Chip), $10-30 (Board)

Kompatibilität: Gut

The STM32F4's 192 KB SRAM provides 3x the 64 KB minimum for predictive maintenance models. A typical vibration classifier (30 KB model, 15 KB tensor arena) uses under 50 KB total — leaving 140+ KB for the application stack, sensor buffers, and communication protocols. The Cortex-M4F's DSP instructions and single-precision FPU accelerate FFT computation for vibration feature extraction. TFLite Micro uses CMSIS-NN optimized kernels on the Cortex-M4, delivering 2-3x speedup over reference implementations. The STM32F4 is the most widely deployed STM32 family — extensive documentation, community examples, and long-term availability (10+ year production guarantee from ST). The 168 MHz clock handles vibration analysis up to ~1 kHz comfortably. For higher-frequency analysis, step up to the STM32H7. Connectivity requires external modules, but industrial environments typically use Ethernet, RS-485, or CAN bus interfaces — all well-supported on the STM32F4.

Erste Schritte

  1. 1

    Set up STM32CubeIDE for STM32F4

    Installiere STM32CubeIDE and create a project for your STM32F407-Discovery board. Use STM32CubeMX to configure I2C for the accelerometer and UART/SPI for communication.

  2. 2

    Integrate TFLite Micro with CMSIS-NN

    Add TFLite Micro to your project. Enable CMSIS-NN and CMSIS-DSP libraries in the project settings. These provide optimized kernels for Cortex-M4 that TFLite Micro uses automatically during inference.

  3. 3

    Build the vibration analysis pipeline

    Sample the accelerometer at 200-500 Hz via I2C with DMA. Compute FFT on 256-512 sample windows using CMSIS-DSP's arm_rfft_fast_f32. Extract spectral features (peak frequency, RMS, crest factor) as model input.

  4. 4

    Train and deploy the classifier

    Train a 1D CNN or dense network on FFT features from labeled vibration data (normal, bearing-wear, misalignment, etc.). Quantize to int8, target model size under 30 KB. Embed in firmware and run inference per FFT window.

Alternativen

STM32H7 with Edge Impulse

3x the clock speed and 4x the RAM for high-frequency vibration analysis (up to 10 kHz). Edge Impulse simplifies DSP. Higher cost, justified for critical machinery monitoring.

ESP32 with Edge Impulse

Built-in Wi-Fi for wireless monitoring at similar RAM (520 KB). Edge Impulse's pipeline handles DSP automatically. Better for retrofitting existing machinery without wired connections.

Häufige Fragen

Warum STM32F4 für vorausschauende wartung?
The STM32F4 offers the best cost-to-capability ratio for standard vibration monitoring. It has 10+ year production guarantees from ST, the largest ecosystem of libraries and examples, and proven industrial reliability. For sub-1 kHz vibration analysis, newer chips add cost without meaningful benefit.
Can the STM32F4 do FFT-based vibration analysis in real time?
Yes. The CMSIS-DSP library's arm_rfft_fast_f32 computes a 512-point FFT in under 1ms on the STM32F4 at 168 MHz. With a 500 Hz sample rate, you get a new FFT window every second — the CPU is idle 99% of the time between FFT computations.
What communication interfaces work für vorausschauende wartung?
The STM32F4 supports UART, SPI, I2C, CAN bus, and USB natively. For industrial environments, Modbus over RS-485 (via UART + MAX485 transceiver) is most common. Ethernet requires an external PHY (LAN8742A) but is well-supported in STM32CubeIDE with LwIP stack.

Vorausschauende Wartung mit ForestHub orchestrieren

Geräte bewerten den Zustand on-device; ForestHub auf dem Linux-Edge-Gateway aggregiert über MQTT/Modbus, schließt über die Linie hinweg und handelt — ein inspizierbarer, auditierbarer Graph.

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