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`EXHIBIT 2004
`EXHIBIT 2004
`
`
`
`Electrical (ECG) vs. Optical-based (PPG)
`Biosensors in Wearable Devices
`
`
`
`There are two primary technologies for measuring heart rate metrics: ECG (electrocardiography) and
`PPG (photoplethysmography). ECG measures the bio-potential generated by electrical signals that
`control the expansion and contraction of heart chambers, while PPG uses a light-based technology
`
`electrical biosensors were found only in high-end medical equipment.
`
`The small footprint, low power consumption and low cost of today’s technology have enabled
`personal wearable form factor for convenience and ease of use. With the advent of low cost but
`highly accurate ECG sensors like NeuroSky BMD101, it has now become possible to design and
`build products and ecosystem around this technology to deliver a wide range of health and wellness
`metrics to individuals as well as healthcare providers and organizations.
`
`NeuroSky BMD101
`ECG-based Solution
`
`Typical PPG-based
`Solution
`
`Directly uses electrical signals produced by
`heart activity
`
`Uses electrical signals derived from changes
`
`Reference signal used for monitoring Cardio
`health as well as for deriving and delivering a
`wide range of health and wellness metrics
`
`HRV (Heart Rate Variability) can be accurately
`derived from ECG data as Peak Intervals can
`be extracted with millisecond level accuracy;
`meaningful HRV data can be obtained with
`short-duration measurements
`
`HR (Heart Rate) can be measured accurately
`on a beat-by-beat basis
`
`during heart activity
`
`Uses ECG signal as reference for HR
`comparison
`
`Peak Interval accuracy is limited by usable
`sampling rate due to high power consumption
`of LEDs; Pulse Rate Variation correlates with
`HRV for longer periods of measurement
`(> 5 minutes) but not for short-duration
` measurement
`
`Only suitable for average HR measurement
`
`Electrical (ECG) vs. Light-based (PPG)
`Biosensors in the Wearable Devices
`
`Email: publish@neurosky.com www.neurosky.com
` © 2015 NeuroSky
`
`
`
`Meaningful readings can be obtained very
`shortly after start-up; does not require long
`settling times
`
`Requires relatively long settling time due to
`the need for measuring the amount of ambi-
`ent light and calculating the compensation
`needed for cancelling its effect; may also
`require compensation of motion artifacts
`
`2.5mW operating power
`
`Approx. 30mW operating power
`
`Built-in oscillator - no external clock required
`
`Very small PCB footprint 3mmx3mm chip, with
`no additional components required
`
`External crystal recommended for accurate
`timing control
`
`Relatively large PCB footprint
`typically 6mmx6mm chip plus additional PCB
`area for MCU, battery management, crystal,
`and LED circuits
`
`On-chip HR measurement
`
`Requires external MCU for HR calculation
`
`SDK (Android/iOS) for easy app development
`and integration
`
`integration in addition to host platform app
`development and integration
`
`NeuroSky biosensors, biometric algorithms, and consulting services deliver intelligence
`and innovation to enable breakthrough wearable technologies. Our full solution technology
`platform enables device manufacturers and enterprise service providers to create best-of-
`breed solutions that can capture, monitor, quantify, and optimize personal physical and mental
`performance with detailed metrics for body and mind. To learn more visit neurosky.com.
`
`PHONE: 408.774.4935
`NeuroSky Inc. 125 South Market St, #900
`
`San Jose CA 95113
`
`Electrical (ECG) vs. Light-based (PPG)
`Biosensors in the Wearable Devices
`
`Email: publish@neurosky.com www.neurosky.com
` © 2015 NeuroSky
`
`