Emerald Motion Monitor

The Emerald™ is an accurate and wearable inertial sensor capable of wirelessly synchronizing data with other Emerald (up to 24). In fact, it is the only IMU on the market that is built specifically for multi-sensor wireless logging, giving you the ability to record kinematic data from anywhere for up to 12 hours.

Emeralds include a full sensor suite of triaxial accelerometers, gyroscopes, magnetometers, and temperature. They maintain precise time-synchronization between Emeralds (≤1ms difference), sampling at 128Hz. Each Emerald has 8Gb of on-board storage for over 20 days of data logging.

The Emerald™ Advantage

Never loses data. Over 30 days of kinematic data is stored onboard each Emerald – keeping our data safe.

Long battery life. With over 16 hours of battery life while asynchronously logging, and more than 12 hours in a synchronous network, the Emerald™ can log data throughout the day without interruption.

Use Anywhere. Say goodbye to million dollar research laboratories and video cameras. Emeralds™ work in any environment and lighting condition, without occlusion or line-of-sight restrictions. 

Wireless synchronization. Up to 24 Emeralds™ exchange data packets to maintain precise time synchronization (≤1ms difference).

Record natural movement. Small, silent, and wireless means you will wear it and forget it – recording natural movement all day long.

Powerful tools for custom applications. The APDM™ software development kit includes support for MATLAB™, Java, Python, and C. We provide cross-platform support for Windows, Mac, and Linux.

  •   Sensor Characteristics





      Sample Rate

      Output Rate¹




      3 axes

      ± 2g or ± 6g

      0.0012 m/s²/√Hz

      1280 Hz

      20 to 128 Hz

      50 Hz

      14 bits


      3 axes

      ± 2000 deg/s

      0.05 deg/s/√Hz

      1280 Hz

      20 to 128 Hz

      50 Hz

      14 bits


      3 axes

      ± 6 Gauss

      0.5 mGauss/√Hz

      1280 Hz

      20 to 128 Hz

      50 Hz

      14 bits

      ¹ Adjustable, up to 24 Emeralds™

  •   Orientation Estimates

      Static Accuracy (Roll/Pitch)

      Static Accuracy (Heading)

      Dynamic Accuracy

      1.15 deg

      1.50 deg

      2.80 deg

      Emerald Orientation
  •   Hardware Characteristics




      Internal Storage

      Battery Life

      48.4 x 36.1 x 13.4 mm (L x W x H)

      < 22grams (with battery)

      6061 anodized Aluminum, ABS plastic

      8 gb (~720 hours storage)

      Synchronous Logging: 12 hours

      Asynchronous Logging: 16 hours

      Emerald Motion Monitoring
  •   Synchronization Characteristics

      Wireless Radio

      Frequency Band


      Transmission Range

      Transmission Range

      Nordic Semiconductor nRFL01+ radio, ultra-low power

      2.40-2.48GHz ISM band, adjustable

      ≤1ms difference, up to 24 Emeralds

      30m line of sight

      10m indoors

  •   Docking Station

      The docking station is used to configure, charge, and download data from the movement monitors. Docking stations can be chained together to enable synchronization of up to 24 Emeralds™ and Opals™.

      APDM Docking Station
  •   External Button

      APDM offers an optional button that fits into the data port of any monitor. This button allows for additional functionality while recording including:

        • Inserting event markers into the data stream
        • Link to example recording: Click here

      APDM External Button
  •   Straps and Clips

      We offer multiple elastic straps that adjust to fit every body size.

      Strap Types and Recommended Placement

        • Small: Wrist, ankle, hand
        • Medium: Bicep, thighs, forehead
        • Large: Waist
        • Sternum: Chest, back
        • Velcro Pucks: Shoulders, hips
        • Clip: Pocket, belt, shoe laces

      APDM Straps

  •   Motion Studio

      Motion Studio is the default software suite bundled with any APDM movement monitor system. It provides an easy way to get up and running collecting data with your Opals. It also provides advanced configuration, recording, real-time visualization, calibration, and data management features.

      Download Motion Studio User's Manual: Click here

      APDM Motion Studio
  •   Mobility Lab™

      Only compatible with Opal™ movement monitors. Mobility Lab™ is the first portable gait and balance laboratory made for clinicians, researchers, and therapists. It was designed by Dr. Fay Horak to streamline gait and balance assessments by making it easy to collect, store, and analyze movement data.

      For more information about Mobility Lab: Click Here

      APDM Mobility Lab
  •   Software Development Kit

      The software development kit gives users the ability to easily integrate Emerald™ movement monitors into their own applications. The SDK includes support for MATLAB™, Java, Python, and C. We also provide cross-platform support for Windows, Mac, and Linux.

      Download Software Development Kit: Click here

      APDM Motion Studio

  •  Mesh Synchronization

      APDM is the only company in the industry to offer mesh synchronized inertial measurement units.

        • Synchronize up to 24 Emeralds
        • Data synchronized within 1ms, typical
        • Over 12 hours of continuous, synchronized logging
      APDM Synchronization Methods

      Technical Description

      In the mesh synchronization scheme, there is no master time source (access point). Instead, each device in the network sends a synchronization packet during its prescribed time slot, enabling each Emerald to compare its clock against the clock of each of the other Emeralds in the wireless network. This comparison allows each Opal in the mesh to create a statistical model of the network time-a distributed statistical clock model-and of its own clock relative to the network time.

  •   Third-Party Synchronization

      Only compatible with Opals. You to easily synchronize your Opal inertial measurement units with third-party systems, such as optical motion capture systems, EMG, or gait mats. Access Points come fitted with a 6 pin digital I/O connector and a 4 pin analog I/O connector.

      We also provide a clock-out signal at 2.56khz, which is used to drive the timing of the entire synchronized system. If fine grained synchronization between systems is necessary, this signal can be used to track the differences in clocking between 3rd party hardware, allowing their data to be precisely correlated.

      Download External Synchronization Sheet: Click here

      APDM Third Party Synchronization

  •   Build your own Emerald™ System

      The highest demanded packages include 3, 6, 10, or 15 Emeralds, but you can choose to purchase any amount of Emerald™ movement monitors to fulfill your system. If you need help deciding how many are appropriate for your task, please give us a call.

      What you need with the purchase of an Emerald™

        • Docking Station (1 for every Opal purchased)
        • Straps (1 for every Opal purchased)
        • Motion Studio Software
        • Computer
  •   4 Emerald™ Package

        • 4 Emerald™ movement monitors
        • 4 Docking stations
        • 4 Body straps (2 wrist, 2 ankle)
        • 1 External button
        • 1 Carrying case
        • Motion Studio software
        • Software Development Kit
        • 1 Year hardware warranty

      Contact us for package pricing: Click here

      APDM 4 Emerald Kit
  •   6 Emerald™ Package

        • 6 Emerald™ movement monitors
        • 6 Docking stations
        • 6 Body straps
        • 1 External button
        • 1 Carrying case
        • Motion Studio software
        • Software Development Kit
        • 1 Year hardware warranty

      Contact us for package pricing: Click here

      APDM 6 Emerald Kit
  •   10 Emerald™ Package

        • 10 Emerald™ movement monitors
        • 10 Docking stations
        • 10 Body straps
        • 1 External button
        • 2 Carrying cases
        • Motion Studio software
        • Software Development Kit
        • 1 Year hardware warranty

      Contact us for package pricing: Click here

      APDM 10 Emerald Kit
  •   15 Emerald™ Package

        • 15 Emerald™ movement monitors
        • 15 Docking stations
        • 15 Body straps
        • 1 External button
        • 3 Carrying cases
        • Motion Studio software
        • Software Development Kit
        • 1 Year hardware warranty

      Contact us for package pricing: Click here

      APDM 15 Emerald Kit





For more technical information about the Emerald™, or other APDM™ products, please contact the sales department.

Email:   info@apdm.com

Phone: 503-446-4055