The AS7026 is an optical sensor developed by ams that is designed to be easily embedded into consumer devices such as fitness monitoring wristbands or smart watches. In what appears to be a first for any such small device, the blood pressure measurements that are obtained from the unit are rated as medical-grade1 (grade B) when tested according to the IEEE 1708-2014 industry standard.
The AS7026 is an advanced optical semiconductor device, and its accuracy is made possible by the highly sophisticated mathematical algorithms that it employs. It is a device that exploits photoplethysmography (PPG) to make physiological measurements. FDA approval for the algorithm is pending and expected to be granted this summer.
The VivaVita mobile reference design uses the AS7026 sensor. Image used courtesy of ams
In its basic form, the AS7062 is an optical module contained in a 6.2mm x 2.8mm x 1.0mm package that consumes very little power. It is designed for 24x7 operation.
It is also available as the VivaVita mobile reference design, also developed by ams, as shown above. The 5 cm by 5 cm unit is designed to work in conjunction with a smartphone, as illustrated. It is supplied with fully-featured mobile apps for both iOS and Android.
In the 5 cm by 5 cm format, the sensor’s capabilities include:
- Heart rate measurement
- Blood pressure measurement
- Vagal tone measurement (activity of the vagus nerve)
For comparison, Omron has taken a different approach to wearable biometric monitoring. Its Project Zero 2.0 is a watch-style wrist device that works with an inflatable bladder, just like traditional blood pressure monitoring devices. The company has announced that it has just received what it describes as FDA clearance for the device, which it has rechristened as HeartGuide.
Project Zero 2.0. Image source Omron Healthcare
Because of the mechanical nature of the device, each measurement takes a significant amount of electrical power when compared to the total charge that a mobile device's battery can store. Omron estimates it will be able to make about 30 to 50 measurements per charge.
There are many consumer-grade mobile devices that can monitor vitals. And, as any medical professional will tell you, the “white coat anxiety” that a visit to the doctor’s office can engender may well be the actual cause of an elevated reading.
While mobile devices induce no such stress, whether their readings are accurate enough for use medical practitioners—especially when measured at home by the patient, themselves—is not clear. Time will tell.
In the meanwhile, expect many hearty rounds of specsmanship and debate from sources within industry, the healthcare establishment and the government.