Movisens Sampling Package

carp_movisens_package adds Movisens sensors as connected devices to a CARP Mobile Sensing (CAMS) study. The sensor computes values such as step count, body position, heart rate variability (HRV) and electrodermal activity (EDA). It sends most of them to the phone once per minute over Bluetooth Low Energy (BLE).

The package uses the movisens_flutter plugin, which talks to the sensor through flutter_blue_plus. No Movisens SDK is involved.

Not medical devices

Movisens sensors are research instruments, not medical devices. Do not use them or their data for medical purposes.

Features

Measure types

The package provides six measure types in the dk.cachet.carp.movisens namespace:

ACTIVITY and HR each produce several data types. See Measure types for the data types, fields, units and example data.

Known issues in version 2.1.0

ACTIVITY, HR and RESPIRATION collect no data. The other measures collect data only when the app is already connected to the sensor or, on Android, the sensor is bonded with the phone. See Measure types and Connecting a device.

Supported models

Not every sensor provides every measure. This table follows the signals that Movisens lists for each sensor:

For the other measures on your sensor and firmware, see Available signals per sensor in the Movisens documentation. A measure whose service the sensor lacks collects no data.

Requirements

See Installation for the platform setup.

How it works

The sensor is a connected device of the phone. The phone connects to it by its name and stores the values that the sensor sends:

flowchart LR
    Sensor["<b>Movisens sensor</b><br/>computes values<br/>every minute"] -->|BLE| Phone
    subgraph Phone["Phone app"]
        direction TB
        Manager["<b>Device manager</b><br/>finds the sensor<br/>by its name"] --> Probes["<b>Movisens probes</b><br/>one per measure"]
        Probes --> DataManager[("<b>Data manager</b><br/>stores or uploads<br/>the measurements")]
    end

• Movisens sensor: computes values such as steps and mean heart rate. It sends each one over BLE 0–84 seconds after measuring it.
• Device manager: MovisensDeviceManager connects to the sensor by its Bluetooth name through movisens_flutter. It writes the wearer's age, sex, height, weight and sensor location to the sensor.
• Movisens probes: one probe per measure turns on the notifications of a service on the sensor. It turns each value into a measurement, stamped with the phone's time of arrival.
• Data manager: stores or uploads the measurements, as the data endpoint of the protocol specifies.

See Connecting a device for how the app binds and connects the sensor.

Next steps