Smart Coaster using ATtiny85 and mlx90615

thingiverse

Connect to usb battery or PC using a cable with only the vcc and gnd wires. The green light indicates no object is on top of the sensor. With a heavy object, push the button, and the sensor will read the temperature. The blue light indicates ice, while yellow or red indicates hot water. There's no hole for the cable in the STL file, so I used a drill to make one. In my code, T1 through T4 are defined as levels for colors and temperatures. I'm using an AtTiny85 microcontroller from CJMCU LilyTiny, the MLX90615 sensor to read temperatures, and a ring of 16 WS2812 LEDs. The libraries I used include Adafruit_NeoPixel for the LEDs and Wire.h for communication with the sensor. Here's my code: ``` #include <Adafruit_NeoPixel.h> #include <Wire.h> #include "mlx90615.h" const byte PIN_NEO = 1; const byte PIN_BUTTON = 4; Adafruit_NeoPixel strip = Adafruit_NeoPixel(16, PIN_NEO, NEO_GRB + NEO_KHZ800); MLX90615 mlx = MLX90615(); // -40 to +115 #define K_TMIN -400 #define K_T1 0 #define K_T2 200 #define K_T3 400 #define K_T4 800 #define K_TMAX 1150 byte r, g, b; int temp; void setup() { pinMode(PIN_BUTTON, INPUT); mlx.begin(); strip.begin(); strip.show(); // Initialize all pixels to 'off' } void loop() { if (digitalRead(PIN_BUTTON) == LOW) { for (int i = 0; i < strip.numPixels(); i++) { strip.setPixelColor(i, 0, 255, 0); } strip.show(); return; } temp = mlx.get_object_temp() * 10.0; // float temp = mlx.get_object_temp(); for (int i = 0; i < strip.numPixels(); i++) { if (temp < K_T1) // -1=azure-> -40° blue { r = 0; b = 255; g = map(temp, K_TMIN, K_T1 + 1, 0, 255); } else if (temp <= K_T2) // 0=azure-> 20° white { r = map(temp, K_T2, K_T1, 255, 0); g = 255; b = 255; } else if (temp <= K_T3) // 21°=bianco -> 60° giallo { b = map(temp, K_T2 + 1, K_T3, 255, 0); r = 255; g = 255; } else if (temp <= K_T4) // 61° yellow -> 90° red { g = map(temp, K_T3 + 1, K_T4, 255, 0); r = 255; b = 0; } else // 91=red-> 115° black { r = map(temp, K_T4 + 1, K_TMAX, 255, 0); g = 0; b = 0; } strip.setPixelColor(i, r, g, b); } strip.show(); delay(2000); } Pinout: P4 to button P0 to mlx (sda) PB0 P2 to mlx (scl) PB2 P1 to led ring ```