Angel - the first open sensor for health and fitness

The first wearable health sensor designed to be open. One wristband - infinite apps.

In partnership with


Hundreds of contributors from all around the world have shown their support for open health innovation. Together, we're out to change the future of health. THANK YOU FOR BELIEVING IN US!

Future of health and fitness

Everyone wants to live better, healthier lives. Angel was designed to make this possible. It's a wristband that monitors pulse, temperature, activity and blood oxygen level. Angel will be able to send this vital information to apps on your smartphone, laptop and possibly even your treadmill.

Angel is the first device designed with developers in mind. Currently most trackers for fitness and health are built for use by a single proprietary app. We want to change that. We are opening up communication protocols, API/SDK and sensor data streams. Ultimately, this will mean more apps to choose from.

Angel is ideal for

Technology and health are an explosive combination - we are completely blown away by the possibilities. These fantastic ideas are already pouring in from our developers:

WORKOUT TRACKER: combine all our sensors together to provide an exhaustive evaluation of your fitness.

SLEEP MONITOR: Angel can analyze both motion and vital signs. This gives a much better insight to what happens when you sleep.

FERTILITY CALENDAR: use temperature sensor to detect ovulation for the best chance of getting pregnant.

SILENT ALARM CLOCK: use the built-in clock and vibrating motor to wake you up without making a commotion.

TELE-NANNY: use temperature sensor to send a text alert when your kid runs a fever.

HEART KEEPER: use raw pulse waveform to detect irregular heart rate and provide an early warning.

GOLF TRAINER: use motion/activity sensor to analyze and improve your shot.

TELE-HEALTH: log the data from all our sensors combined and provide on-demand updates to your physician.

MARATHONER: use temperature sensor to detect potentially fatal heat strokes.

How is Angel different?

Angel is open to give consumers the freedom to choose any app in fitness, nutrition, wellness and healthcare.

Angel sports a one-of-a-kind integrated optical+acoustical sensor for robust heart rate extraction. 

Angel is the only sensor to give developers real-time, raw data access.

Angel uses standard and open Bluetooth Low Energy profiles, so it will work with many popular fitness apps such as: Endomondo, Wahoo Fitness, RunKeeper, Strava, and others.

Available in black and white.

Measuring your vital signs

Angel uses an array of precision sensors to analyze:

  • Heart rate
  • Skin temperature
  • Blood oxygen (SpO2)
  • Physical activity (such as calories, steps, sleep and activity modes)

These metrics can support a wide range of applications, from smarter fitness to advanced medical diagnostics. Raw sensor data can be used for medical research.

Raw data stream. Can you see the heart beats?

Technical features in comparison.

Made for developers

An open eco-system is not just an afterthought for Angel. We are already reaching out to researchers and medical experts to ensure Angel can help bring their ideas and dreams to life. Developers will be able to use Angel to create apps for iPhone, Android, and other devices that support Bluetooth 4.0.

Our SDK, drivers and app templates will be released as open source.

Key features

  • Apps: will ship with Foundation Apps for device configuration and user data access.
  • Connectivity: Bluetooth Low Energy (supported on iPhone 4S and newer, as well as select Android phones). Will work with many popular fitness apps.
  • User interface: LEDs, vibrating motor, buzzer. Detect basic hand gestures.
  • Logging: record data for up to 7 days.
  • Timepiece: built-in real-time clock, configurable alarm clock.
  • Elegant and simple: small and unobtrusive wristband.

Many apps available on AppStore could use Bluetooth Low Energy to connect to Angel

The above free Foundation Apps will ship with Angel.

Angel’s Story

It took us almost two years to get this far, but it was a road worth taking. We have produced and tested several variants of our sensors to achieve optimal performance. We have an engineering prototype designed to calibrate and optimize our technology. Angel already speaks Bluetooth 4.0 and happily communicates its data to our smartphones. We have price estimates and timetables from several manufacturers. With your support, we are hoping to take Angel through the final development stages and enter the manufacturing process.

Early sketch of Angel and test models.

Evolution of sensor modules. Bluetooth Low Energy testing setup.

The first hand-crafted prototype being tested with iPhone 4S.


We have prepared some very special perks for our Indiegogo supporters.

Team Angel

An unlikely combination of passionate people have gelled together to put Angel in your hands. We have worked with some very special partners and consultants along the way. We are: hardware engineers, medical experts, embedded software developers, industrial designers, web designers, and beyond.

Among ourselves we have several decades worth of experience in consumer electronics. All of us share a common belief in an open future for digital health. Angel is backed by Seraphim Sense Ltd – a company we created to be our home base in this endeavour.

Recently we got some good vibes in the media. It is impossible to underestimate the impact of hundreds of people who reached out to us since then. You are all part of our team now! We are humbled and honored by your support.

What’s Next?

Angel is still an experimental device and makes no medical claims. In the future, after Angel ships, we are planning to apply for FDA approval so Angel can become a medical grade device. To help us make this happen, we'll be asking you further down the road to opt-in to our clinical studies program.

Over the next few weeks, the first functional specification draft will be released for review to involve the community in crafting a robust and powerful sensor API for future apps. If you are a maker - visit our website and let us know what tools and functionality your app requires.

In the future, we imagine devices like Angel doing amazing things. It is exciting even to try and guess where this technology could take us in just a few years, but to get there faster, we need health innovation on a massive scale. Angel was built to enable just that!

Angel is an open product and thus crowdfunding is in our DNA. With your support, we hope to make Angel a reality and promote open technologies in digital health.

Help us spread the word by sharing this campaign with family and friends.

Good vibes

(Click below to read the article)



1. When will Angel be available?

Angel is currently in prototype phase. We recently launched a crowdfunding campaign in order to raise funds toward production.Our goal is to have Angel ready to ship by April of 2014. 

2. Material & Sizing & Colors

  • Angel is a flexible bracelet that is comprised of a silicon polymer and stainless steel. These materials are hypoallergenic, lightweight, and made to withstand the wear and tear of daily use.
  • Proper adjustment is important because our sensor requires a relatively snug fit. Your device will arrive with a set of clasps in various sizes. This will allow for adjustment of the wristband to fit your wrist (sizes ranging from 4-8 inches). Angel is currently offered in black or white.
  • NOTE: Angel is still under development, so minor design changes are possible.

3. Battery Life & Charging

  • We expect the battery to last approximately one week (7 days), but we are still optimizing. We are also working on perfecting our charging solution.
  • Whether Angel will have wired (USB) or wire-free charging, we are designing it to support the fastest charge and most power-efficient solution in order to minimize the time away from your wrist.
  • Angel can let you know your battery is low via an alert or a vibration every few minutes. You get to choose the alerting style you like best!

4. Water Resistance

Angel is designed to stand up to day-to-day use. It is Ok to wash your hands, take a shower, workout, etc. We are still hoping to achieve full water resistance for swimmers, but cannot promise that yet, as several design constraints need to be finalized.

5. How is Angel different from the other wristbands out there?

  • Angel is the first open sensor for health and fitness.
  • Angel does not limit its users to proprietary interfaces. It was designed from the ground up to be open, both in hardware and software. We look forward to the innovations and optimizations that come from an open platform.
  • The metrics gathered by our sensors go beyond the basics gathered by other fitness sensors, and will be able to provide the user with vital data that can be used for prevention.

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