Author Andrei
12/08/2019
Let's see another cool project I've found on hackaday. This is a fitness tracker with some cool sensors.Fitness trackers have become a popular piece of consumer electronic equipment, with a range of models from a variety of manufacturers. Many of these commercial offerings, however, leave the consumer with the prospect of their data being drawn off to a cloud server and sold to the highest bidder, trading convenience for a loss of privacy. If only there were a fitness tracker offering complete control!

The OpenHAK is an open-source fitness tracker in a 3D printed wristwatch case that measures your heart rate and counts your steps, offering the resultant data for you to collect via Bluetooth. At its heart is a Sparkfun Simblee module, with heart rate sensing through a Maxim MAX30101 and step counting .by a Bocsh BMI160.

It’s designed for expandability from the start with a header bringing out useful interface lines. In the prototype, they’ve used this to support a small OLED display. The result is a fitness tracker watch that may not match some of the well-known proprietary devices, but which remains completely open and probably costs a lot less too.

Out of the box, the OpenHAK works, and is advertising itself to connect to your phone/tablet. Once connected, the OpenHAK will go through a cycle of deep sleep for 10 minutes, then waking up for 30 seconds to take your pulse and send all of its new data to your phone/tablet. This includes a time stamp, steps, heart rate, and battery level.

There's room for three more data points that we are not using that you could use for all kinds of stuff. Other sensor readings from something you've hacked into the OpenHAK, for example. Our current prototype send the temperature taken from the MAX sensor, which is right on your wrist, as an example of using the auxiliary data slots.In order for you to build and use your own add-ons, you have to have access to pins on the Simblee. We have broken out 10 pins! Exposed for user hacking.

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