Surrey Fluid Sensor Development Initiative

The Surrey Fluid Sensor Development Initiative offers bespoke, cost-effective measurement solutions for a wide range of sectors including Formula 1/motorsport, avionics, UAVs (unmanned air vehicles), healthcare, commercial agriculture and elite sport.

Our high-precision pressure-based velocity probes, designed and fabricated at Surrey, can be produced in complex configurations, for a fraction of the cost of commercially-available sensors. Offering good functionality at a small fraction of the cost of other available commercial systems, this gives customers the option of setting up very large arrays of sensors, enabling more robust measurement than conventional systems.

We are unique in being able to prototype sensor systems in any configuration, using techniques including 3D printing, within a very short turnaround time (generally weeks). We can also produce low cost, miniature constant-temperature and constant-current anemometer systems for turbulence and temperature measurements.

Part of the University of Surrey’s experimental aerodynamics research programme, the Surrey Fluid Sensor Development Initiative is led by Dr David Birch and Dr Paul Nathan. In providing this service, we draw on decades of experience in designing and managing fully-automated experimental measurement systems for the NCAS EnFlo national laboratory.

Case studies

Wind monitoring
Designed for use by meteorological monitoring stations, our compact, low-cost wind monitoring system is based on our omnidirectional probe concept. The system is capable of measuring wind velocity and direction, temperature and humidity and provides a much more compact solution than conventional ultrasonic sensors. Technology currently under development will add an air quality measurement system as well.
Respiratory diagnostics
Providing a low-cost solution in the healthcare industry, our patented prototype sensing system could be used in the non-intrusive diagnosis of a variety of chronic and acute respiratory conditions. The system has recently undergone pre-clinical trials and is currently being developed in collaboration with commercial and clinical partners.
Athlete performance
Custom-designed, very-high-precision directional velocity probes have been used to provide elite athletes and their coaches with the detailed information they need to fine-tune and target their efforts during training.
Formula 1 avionics
Modern Formula 1 cars can drive faster than some aircraft and, just like aircraft, Formula 1 car performance can depend heavily on the local wind conditions. We have produced compact, high-precision 'avionics' packages for use in testing the latest Formula 1 designs.

Our capabilities

Multi-hole velocity and vorticity probes

Thermal anemometry systems

Pressure sensing systems

  • High-bandwidth, low-cost miniature pressure sensors for large- and very-large arrays
  • Rapid-prototyping of models, with model-integrated surface pressure arrays
  • Flush -mounting, medium-bandwidth surface pressure sensor arrays

Measurement instrumentation

  • High-precision, high-bandwidth analogue signal multiplexers and conditioners
  • Networked data acquisition and telemetry systems
  • Bespoke, turn-key sensing, acquisition and data management systems
  • Automated experimental motion and measurement systems

Examples of our capabilities

Below are a few examples of sensors we have developed in response to a particular customer need. All sensors can be supplied independently, or together with integrated transducer arrays and data acquisition/management systems.


New product!

Miniature air data probe

This directional velocity probe system offers unparalleled functionality in a highly compact, minimally intrusive package. This probe is undergoing certification for use on aircraft, but may equally be used in wind tunnel measurement or motorsport track testing. Features include:

  • Seven-plus-one hole probe for velocity measurement, referenced to true local static pressure;
  • Seven-channel, temperature-compensated differential pressure transducer array;
  • Absolute static pressure and local air temperature sensors for high-accuracy data reduction;
  • Inertial positioning sensor for automated probe alignment; 
  • Humidity sensor for density correction and condensation warning;
  • 16 bit, 1000 Hz data acquisition, streaming via RS-485;
  • Integrated sting and case heaters for de-icing;
  • Compact, in-line sensor package: 28 mm diameter, 80 mm long;
  • Solid stainless steel construction;
  • Sting diameters down to 3 mm OD available.

Omnidirectional velocity probes

We can produce probes with complex geometries such as this new 37-hole, 12mm diameter omnidirectional velocity probe, using high-resolution rapid prototyping techniques. Together with our low-cost, small-size transducer arrays, these probes offer excellent range and precision, even functioning in regions of reversed flow. Typical applications include:

  • High-precision air data systems
  • Meteorological monitoring stations
  • Measurement of mixing/swirling flows.

3D-printed integrated velocity probes

Manufactured from acrylic, low-cost probes such as the standard Pitot-static probe shown here, include a temperature-compensated differential pressure transducer system with an analogue-to-digital converter for low-noise communications. Direct-to-USB versions are also available. Typical applications include:

  • Low-interference, high-bandwidth measurements
  • Micro-UAV airspeed systems
  • Custom/unconventional probe fabrication
  • Large probe arrays

Miniature multi-hole velocity probes

Manufactured from stainless steel, these micro-miniature conventional seven-hole probes have an outer diameter of 1.8 mm and a 45˚ conical tip. The probe shown here is pictured next to the head of a pin. Typical applications include:

  • Measurement of highly sheared flows
  • Measurement of sensitive flows
  • Measurement in small facilities or of small models

Miniature thermal anemometry probes

These miniature single-sensor hot-wire probes feature a sting and prongs of stainless steel, with epoxy filler, and are designed for low-interference intrusive flow measurements. Typical applications include:

  • Measurement of fine-scale turbulence
  • Model-integrated stings
  • Measurement in small models

High-sensitivity vorticity probes

A custom-designed 19-hole vorticity probe, this probe provides local spatial velocity gradients and more precise flow angularity measurements than conventional five- and seven-hole probes. Typical applications include:

  • Measurement of swirling flows
  • Velocity measurements requiring very high accuracy
  • Measurements requiring very high reliability or robustness 

Custom probe configurations

Our custom-made probes are designed for specific applications and requirements. These can be constructed from stainless steel (for durability and use in harsh environments) or plastic (for a lower cost solution), and using our high-resolution 3D printing capability, even highly complex, exotic probe configurations are possible.

Custom instrumentation

Some examples of the bespoke instrumentation systems produced, designed by Dr. Paul Nathan, are shown below. All instrumentation systems may also be supplied with fitted ABS or UA enclosures (not shown).

New product!

Multichannel modular pressure sensor network

Compact, modular array of up to 64 pressure transducers. Transducers are installed in 8-element units, and each unit may have a different full-scale range; this modularity provides maximum flexibility in the application. Transducer units are self-detecting and factory-calibrated, allowing the user to easily swap elements while in use. Features include

  • Array of 8, 16, 24, 32, 40, 48, 56 or 64 transducers, either differential or absolute;
  • Full-scale sensor ranges down to 250 Pa; 
  • Local temperature and absolute (atmospheric) pressure sensors included, for maximum accuracy;
  • Humidity sensor for density correction and condensation warning;
  • Remote fluid temperature sensor also included, for local state estimation; 
  • IMU for orientation and vibration detection;
  • External trigger input;
  • 16 bit, 1000 Hz data acquisition, streaming via USB;
  • USB powered - no additional external power supply required;
  • Supplied either as OEM unit (pictured) or with protective enclosure.

Custom data-acquisition hardware

(New!) Simultaneous sampling data acquisition system, streaming (via USB) at up to 62 kHz. 8 analogue inputs, 18-bit fully-differential with adjustable range up to +/- 10 V. Also includes 8 digital I/O channels, one output clock channel and one 12-bit analogue output. Hardware and software triggering capability. May also be upgraded for on-board power, storage and wireless communication for telemetry applications.

Low-cost, low-noise constant current anemometer

This constant current anemometer design uses a two-stage gain and two-stage active filter and buffer. Ultra-low noise levels are achieved through active cable compensation and shielding. A small-footprint surface-mount version is also available.

High-precision DC motor speed controller

PID bi-directional MOSFET motor controller with encoder feedback.

Medical applications

Fluid sensing systems are also being developed for applications in clinical research and medical diagnostics, in conjunction with the University of Surrey Centre for Biomedical Engineering.

Thermal anemometry probe for in-vivo blood turbulence measurement

A specialized probe has been constructed, having a flexible sting and using only bio-compatible materials, capable of being introduced into large blood vessels by means of a standard 16-gauge cannula. Blood turbulence levels have been associated with diseases of the circulatory system.

Ultra-high-sensitivity, high-speed flow meter for respiratory diagnostics

This prototype sensing system, which has recently undergone pre-clinical trials, may be used in the non-intrusive diagnosis of a variety of chronic and acute respiratory conditions. The sensor is currently being developed in collaboration with commercial and clinical partners.

Redundant accelerometer arrays for human gait analysis

This prototype, wearable sensor array can record parameters such as the sagittal hip flexion/extension angle (in the configuration shown). The large array of small, low-cost sensing elements minimizes error while enabling it to be used outside of the laboratory environment.

Drivers and software

System drivers (version 1.2) for the Mk-II Fast Respirometer prototype. System requirement: Windows 7 or later, 3 GHz with 4 GB RAM.

Drivers V1.2 (1212.8KB)


System drivers (version 2.01) for the micro-air data probe. System requirement: Windows 7 or later, 64 bit, 3 GHz with 4 GB RAM.

Probe drivers V2.1 (562.89KB)


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