When a person goes to sleep, their heart rate decreases an 8%. So our lamp will provide a bright light when the user goes to sleep and as his pulse decreases the brightness of the lamp will fade until it turns off when the user is asleep.
A LED strip lamp is connected to a pulse sensor. When the sensor detects a pulse the LED strap turns on with a brightness according to your pulse. If your pulse is high the LED strip will shine with a high intensity. If your pulse is low the LED strap with less intensity.
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Step 1: Step 1: Tools and Materials
- 3D Printer or 3D Printing Service
- Arduino UNO/ Arduino Nano
- 1m Neopixel LED strip 5050 RGB SMD 60 Pixels IP67 Black PCB 5V DC
- +5V Power Supply
- 1000 microfarads Capacitator (*1)
- 470 ohms Resistance
- Pulse Sensor
(*1) When using a DC power supply, or an especially large battery, we recommend adding a large capacitor (1000 µF, 6.3V or higher) across the + and – terminals. This prevents the initial onrush of current from damaging the pixels.
Step 2: Step 2: Building the Circuit
The heart rate sensor has to be connected to the arduino board 5V, to an analog pin, in this case we chose A0 and to the ground.
The LED strip is more complex. There is a cable that must be connected to a digital pin, we chose pin 6, one goes to the ground and the last one to the power. We can either connect the arduino to a 5V bench power supply or to an external battery. If you choose the bench power supply you won't have any problem. However if you choose to use an external battery we strongly recommend to include a 1000 µF capacitator for batteries with a voltage higher than 6,3 V.
You can find more information on external power supplies on the following link: https://learn.adafruit.com/adafruit-neopixel-uberg...
Step 3: Programming
The next step is to make the Arduino program.
The first step is to install the Adafruit Library. You can find it here: https://learn.adafruit.com/adafruit-neopixel-uberg...
At the beginning of the program we must import the AdafruitNeopixel library and program the setup.
The second picture shows the loop, where the program is executed. Every time our heart rate increases or decreases the intensity of the light changes, from light blue for low heart rate to bright white for high heart rates.
The third picture shows the program that will follow the LED strip. This program is at the end. The LEDs in the strip will turn on one after the other.
Step 4: Building the Prototype
Now it's time to build the lamp and test the arduino program.
The shape is a simple cilinder so you can either buy a cilindric lamp or make a SolidWorks file and print it
It has to be a translucid material so you cannot see the interior of the lamp but the light can still go out.
To conclude the project you must test the lamp. If the LEDs start behaving strangely you must look if the LED strip is given enough power. The NeoPixel LED strip is quite powerful and if not given enough power it won't work properly.