New SDP3x Differential Pressure Sensor from Sensirion Allows Precise VTOL Functionality for Drones

September 08, 2017 by Heather Hamilton-Post

Sensirion’s SDP3x differential pressure sensor offers high sensitivity at low airspeeds—in the smallest package on the market.

Sensirion’s SDP3x differential pressure sensor offers high sensitivity at low airspeeds—in the smallest package on the market.

Recently, Sensirion introduced the SDP3x, a differential pressure sensor available in an airspeed sensor development kit for vertical take-off and landing (VTOL) and fixed-wing UAV applications.

It was developed in partnership with PX4 Pro and is entirely integrated with the open source autopilot, including a full aerodynamic software compensation mode for the sensor and pitot tube—a plug-and-play solution that also offers the smallest differential pressure sensor available today. Aside from being useful in VTOL drones, it’s potentially useful for wearables too.


All images courtesy of Sensirion


SDP3x uses Sensirion’s CMOSens® sensor technology, combining the sensor, signal processing, and digital calibration on a CMOS chip. Differential pressure is measured via a thermal sensor element with flow-through technology:



Sensirion claims that the SPD3x has the current title of "smallest differential pressure sensor". At 5mm x 8mm x 5mm, it's certainly small enough for use in most drones.

Responding to a Growing Need for Precision

As the coastal US prepares for and attempts to recover from increasingly violent hurricanes, drones are again being put to work. Drones used for disaster recovery may soon be responsible for things like identifying people in need of rescue, which means they need to be able to travel safely and collect data. The use of drones use in agriculture, business, and even medicine is growing, too, but storms like Hurricane Harvey make them even more necessary.

Approximately one year ago, the Federal Aviation Administration began handing out commercial drone licenses, and Harvey marks the first major storm in the US since. In the wake of the storm, companies like AT&T are using drone fleets to identify downed cell towers and lines. BNSF Railway is using drones to survey railroad conditions to expedite repairs. Still other companies are using drones to evaluate insurance claims for the thousands of families filing them after the storm.

In places where things like weather conditions are difficult, VTOL is especially important, and, while a number of startups are exploring ways to develop the VTOL flying car we were all promised as children, drone companies are more focused than ever on providing better user experiences for VTOL drones.

Highly precise drone applications call for technology that is up to the task. Where most airspeed sensors require constant calibration, Sensirion’s SDP3x is fully calibrated and temperature-compensated, which allows it to give reliable readings at low airspeeds. High sensitivity at low airspeeds provides for closed-loop control during the transition phase from hovering to forward flight, which makes VTOL drones safer and more reliable.

“The calibration-free setup enables instant launch of VTOL drones, dramatically increasing the user experience for end users,” says Lorenz Meier, founder and chief architect for Px4-Pro.

Featured Specs

  • All SDP3x
    • ​​Reflow solderable
    • Shipped as tape and reel
    • No zero-point drift
    • Multiple I2C addresses
    • Sampling time: 2kHz at 16-bit resolution
  • SDP31
    • ​​Digital version (I2C)
    • Pressure range: +/- 500 Pa
  • SDP32
    • Digital version (I2C)
    • Pressure range: +/- 125 Pa
  • SDP36
    • Analog version
    • Pressure range: +/- 500 Pa
  • SDP37
    • ​​Analog version
    • Pressure range: +/- 125 Pa

More Information about Sensirion: