Biological & Environmental Feedback LED Wristband

This is where the fun really begins for the open-source community. We have been working on merging the heartbeat and audio into one impressive visualization. For all the non-programmers a package with our own visualization algorithms will be included but for anyone with Arduino programming knowledge feel free to edit the code to make a combined visual that makes sense to you. Our current algorithm uses a wheel of color that changes based on heart rate and resets every time the beat hits it's loudest. This allows for an understanding of the wearers heart rate as well as an audio visualization.

The microphone input is functioning with the help of a simple LM386 circuit. The following link is the link we used for the amplification from the microphone: http://lowvoltage.wordpress.com/2011/05/15/lm386-mic-amp/. This allowed for a larger range of values from the Analog Input. The simple analog read example can be used to test the circuit. After testing the circuit we added the analog input part of the code to our light strip code. The light strip code now presents the viewer with visualizations of two inputs, audio and heart rate.

Powering three strips of LED's will be up to a Li-Po battery which is recommended for use with NeoPixels by adafruit. We chose a 3.7V 1200maH battery because of its size, weight, and capacity. It is important for the wearer to feel comfortable with the wristband throughout a show. Also, because the lights will be blinking the current draw will be lowered and this will extend the lifetime of the battery. With all three light sequences running (a total of 21 LEDs) off a supply the highest current draw ranged around 600ma with a more regular draw of 170 - 300 ma. With one battery that would make the lights last over 2hrs and just by adding another lightweight slim battery we could extend the time of the lights to well over 4hrs. 

Working on programming the LED strip to visually communicate the heart rate and activity of the user. The example file that you can download from pulse sensor's website utilizes an interrupt that determines a BPM variable. Using this variable we can change the rate of blinking. By setting an average control heart rate we can shift the colors to visualize activity.