AUTOMOTIVE
FlowNodes – Miniature Wireless Gas Flow Velocimeters
Project Overview
FlowNodes bring wind tunnel testing into real-world conditions using ultra-compact, wireless flow sensing nodes. These devices measure aerodynamic surface pressures in live flight and road tests, enabling accurate aerodynamic performance analysis outside controlled environments.
HARDWARE | FIRMWARE
Client Requirement & Objectives
Miniature Sensor Design
Develop a wireless node with a maximum diameter of 15mm and a total height of 5mm, including battery and enclosure.
High Sensor Density
Each node must integrate 15 MEMS pressure sensors and a Wi-Fi module for wireless data retrieval after tests.
Onboard Storage
The system needed flash memory capable of storing over 1 million records, with pressure readings sampled every 100 milliseconds.
Post-Test Data Transfer
All stored test data had to be reliably transferred to a laptop via Wi-Fi for further aerodynamic performance analysis.
System Design & Build
Compact PCB Layout
Designed a complex 6-layer PCB with a 15mm diameter and 2mm height, fitting all 15 MEMS sensors on one side and all other components—including microcontroller, flash, and Wi-Fi—on the reverse.
Ultra-Low-Power Components
Selected the world’s smallest Wi-Fi module and microcontroller at the time, optimized for space and minimal power consumption.
Precision Data Logging
Engineered firmware to sample and log 15 sensor readings every 100ms, ensuring consistent recording during hour-long tests. .
Seamless Wireless Transfer
Integrated a Wi-Fi data offloading mechanism that initiates post-test, transferring approximately 4MB of data per session for offline analysis.
Key Challenges & Solutions
Miniaturization Constraints
Fitting all components within a 15mm x 2mm volume was a major design hurdle. We overcame this with meticulous 6-layer PCB routing and custom placement strategy separating sensor and processing elements.
Thermal & Power Optimization
Operating 15 sensors and a Wi-Fi module within such a small form factor posed heat and battery life challenges. We used power-efficient firmware scheduling and deep-sleep states to manage heat and extend runtime.
High-Speed Logging Reliability
Achieving consistent logging every 100ms without data loss required optimized memory access and sensor polling routines. Flash storage was fine-tuned with buffer caching and efficient write cycles.
Post-Test Data Handling
STransferring high-volume data wirelessly after tests demanded a robust file transfer system. We implemented a Wi-Fi-enabled bootloader to reliably stream data in batches without overwhelming the device or network.
Project Tech Stack
Silicon Labs
STM 32
Windbond
WiFi
Client
FlowNodes specializes in the development of ultra-compact, wireless aerodynamic sensor nodes designed for high-precision wind tunnel testing and flow diagnostics in aerospace and automotive applications.
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