I started to think more and more that time is passing and we are getting close to the end of this challenge. So I started to mount the various project parts together. Here is a picture of the main unit:
I have built the main unit on a prototype board, which I have placed in a project enclosure that I then mounted in on top of a bicycle helmet. It is not really limited to bicycle helmets; it can be placed on any sports helmet, and with a custom PCB design it can be placed on a hat or just a head-band. For now I will keep it at a “project” level and focus more on functionality and performance than on style and miniaturization.
Looking at the picture above we can see at the bottom right side the Analog Devices accelerometer EVAL-ADXL375Z evaluation board, and next to it towards the left the EVAL-ADXL362Z evaluation board. Right at the bottom of the prototype board we can see the QAM-RX2 433 MHz receiver, which captures the data from the Electrocardiogram (ECG) unit.
Right in the center we can see an Arduino nano board that controls both EVAL-ADXL375Z and EVAL-ADXL362Z evaluation boards through their SPI interface.
Right above the Arduino nano I have placed two voltage regulators, one 5V and one 3.3V, meant to power up peripheral sensors and modules that will be connected to the 25 pin connector at the top. The battery is not shown here, but it will be made of two 3.7V Lithium-Ion cells. In this picture you can also spot a REED relay; I will explain later what I use the relay for.
This is where I got so far with my wearable impact and health monitor system. I will come back with other updates as I get more work done.
Best Wishes,
Cosmin