The MAX-HEALTH-BAND wrist-worn heart-rate and activity monitor provides a simplified means to extract high-accuracy vital signs and raw data from health sensors for wearable designs. This unique evaluation and development platform uses the MAX86140 optimized optical pulse-oximeter/heart-rate sensor and the MAX20303 wearable power management solution, and showcases Maxim’s motion-compensated health sensor algorithms. The MAX-HEALTH-BAND streams algorithm output and raw data from the health sensors via Bluetooth® onto a smartphone app for customized algorithm development. The platform is also available for white-box license.
In addition to raw PPG and accelerometer data, the MAX-HEALTH-BAND monitors steps, activity classification, heart rate, and interbeat intervals for heart-rate variability. The MAX-HEALTH-BAND comes with a wrist-worn heart-rate and activity band, a USB charging cable, and instructions for downloading the Android-based application.
What You Need
Power On/Off and Wearing
During the first few seconds after powering on the watch, the watch sensor (the surface that normally faces the wrist when worn) should be off the wrist and exposed to ambient air. This is required for proximity detection and for the algorithm to work properly.
Figure 1. Watch placed approximately one finger width above the wrist bone.
NOTE: After powering up and placing the watch on the wrist, it can take up to one minute for the algorithm to initially report a heart rate value. In the interim, the display shows a short line ("-").
NOTE: If the watch is powered on or power-cycled while being worn on the wrist, lift the watch one inch away from the wrist surface for more than one second; this updates the proximity setting without you needing to completely take off the watch. This can be done at any time (e.g., during any operation mode, and even during data logging). During the process, be sure not to insert fingers in the one-inch clearance space between the watch and the skin. Make sure the strap is tightly fitted around the wrist afterwards.
The watch has a screen showing remaining battery life. Currently, the device does not have a warning for low battery.
The watch can be recharged using a micro-USB type-B cable (provided). When connecting the watch to a charger, the device vibrates and displays a recharging screen. Removing the watch from the charger will causes the device to vibrate.
The watch has the following modes: sampled mode and continuous mode. The operating mode can be changed from the watch by pressing the button down for one second. The watch vibrates as an indicator of mode change.
The watch is in sampled mode by default. In this mode, the device measures the heart rate every five minutes or whenever the button is pressed. Sampled mode display items are shown in the figure below.
Figure 2. Sampled mode display.
In continuous mode, photoplethysmogram (PPG) and acceleration are sampled constantly at 100Hz and averaged over four samples. Heart rate (HR) is estimated once per second. In addition, a small heart is shown in the display's upper-left corner while the device is in continuous mode. Continuous mode display items are shown below.
Figure 3. Continuous mode display.
Heart Rate Display in Both Modes
The following heart rate display items appear in both sampled mode and continuous mode.
Figure 4. Heart rate display.
For data logging, the user must install the provided Health Map app for Android.
To ensure uninterrupted data logging and watch connection, change the display setting of the Android phone or tablet to keep screen always ON before running the app.
Installing the App
To install the Health Map app:
Connecting to an hBAND Watch
The app's initial start-up screen is blank with a SCAN button at the top right corner.
To connect the Health Map app to an hBAND device:
The main screen (see figure below) is displayed after a successful connection.
Figure 5. Health Map main screen.
The watch can measure both optical count and HR. By saving data to a database, users can access the raw optical count, computed HR based on an internal algorithm, and other information.
To start data collection:
Figure 6. Pop-up menu.
The Raw Data icon on the main screen is automatically turned to ON.
Data is now being stored in the device memory. As long as the Bluetooth connection remains, data is transferred (and deleted) from the watch memory to the phone database. If the Bluetooth connection is interrupted while data is being collected in the device memory, new data is not lost, but is streamed to the phone as soon as the Bluetooth connection is reestablished.
NOTE: Raw data refers to the optical and accelerometer data before it is fed through an internal algorithm.
To stop data collection:
Viewing Real-Time Data
To see real-time charting of raw data:
Figure 7. Real-time charting window.
To close the charting window:
NOTE: When the charting window is open, data is stored locally on the watch, but it is not streamed to or synchronized with the database on the phone until the charting window is closed. To ensure proper saving of data to the database, exit the real-time charting window and return to the main screen promptly after validation is complete.
Exporting Real-Time Data
The user can export, or copy, the SQLITE database to a .csv file. When exporting, the original data remains in the SQLITE database, and newly collected data is appended to it. Subsequent exports of database data into .csv files contains both previous and new data. Therefore, when starting a new study, it is recommended that the user clears the database by deleting the SQLITE files before data acquisition. New SQLITE files are created automatically in the next data-logging session.
To export data to .csv format for analysis:
For more details regarding the output file format, see the "hBAND User's Guide."
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