From fmattiussi on Hackster.io:
My project is very simple and easy to accomplish. I chose this project to monitor the temperature of my room because having a guinea pig I should know the temperature because too low or too high could die U_U.
My NeoPixel has 12 LEDs, the base temperature is 11 ° C and the maximum is 30 ° C, each LED has a temperature range of 1.5 (ie the first LED will light if it is at a temperature Between 11 and 12.5 degrees). To understand the temperature I printed on a sheet of temperature and then after bending I put it in the NeoPixel.
Featured Adafruit Product!
NeoPixel Ring – 12 x 5050 RGB LED with Integrated Drivers: Round and round and round they go! 12 ultra bright smart LED NeoPixels are arranged in a circle with 1.5″ (37mm) outer diameter. The rings are ‘chainable’ – connect the output pin of one to the input pin of another. Use only one microcontroller pin to control as many as you can chain together! Each LED is addressable as the driver chip is inside the LED. Each one has ~18mA constant current drive so the color will be very consistent even if the voltage varies, and no external choke resistors are required making the design slim. Power the whole thing with 5VDC and you’re ready to rock. (read more)