Build and program a string of LEDs to reflect your mood based on your heart rate.
Step 1: Materials
1- 20 RGB neopixel LEDs
3-Computer with Arduino software
6-9V battery holder
8-Access to soldering
Step 2: Building a Chain of LEDs
First of all you must disconnect the LEDs from the board they are packaged on and solder them together as a chain. Use wire to connect the arrows in the centre to the the arrows in the centre of the next LED. When finished continue to connect the power (+) to the next LED´s power (+) and the ground (-) to the next LEd´s ground. Make sure the wires are connected correctly or the chain of LEDs will not work.
Step 3: Connecting LEDs to Arduino
Once your chain of LEDs is ready you must connect the 3 remaining wires at the end to the Arduino Duemillanove board. Connect the ground (-) to the ground plug, the power (+) to 5V and the directional to the number 7. Connecting the Arduino to the LEDs will provide the LEDs with the power and information they need to do their job.
Step 4: Connecting Pulse Sensor to Arduino
Now you must connect the three wires on the pulse sensor to the Arduino board. The red must go to power, the black to ground and the purple to 0A. Now we have a string of fully functioning LED´s connected to an Arduino and a pulse sensor. Let´s get coding!
Step 5: Writing Code for the Arduino
Open Arduino software on your computer and connect it to your computer with a USB connecting cable. Use sample examples from the Arduino website that control the pulse sensor and LEDs. You are telling the Arduino to measure the user´s pulse and send a signal to the chain of LEDs to act by representing a certain colour depending on heart rate. In this case a heart beat of less than 97 BPM will trigger the LEDs to be blue and inversely a heart beat of more than 97 BPM will provoke them to become yellow. In addition to this the LEDs initialise as white and switch off after 10 seconds of non use.
This information is saved on the Arduino board and allows us to use the pulse sensor to measure the user´s mood at a basic level, through heart rate.
Step 6: Connect Battery and Place on Umbrella
The last step is to place the 9V battery in it´s holder and connect to the Arduino so it can be powered without needing a connection via wire to power outlet. Now the string of mood LEDs is ready to be sewn into the Mood Umbrella and you are ready to share your mood with the world!