#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,16,2);
byte gauge_empty[8] = {B11111, B00000, B00000, B00000, B00000, B00000, B00000, B11111}; // empty middle piece
byte gauge_fill_1[8] = {B11111, B10000, B10000, B10000, B10000, B10000, B10000, B11111}; // filled gauge - 1 column
byte gauge_fill_2[8] = {B11111, B11000, B11000, B11000, B11000, B11000, B11000, B11111}; // filled gauge - 2 columns
byte gauge_fill_3[8] = {B11111, B11100, B11100, B11100, B11100, B11100, B11100, B11111}; // filled gauge - 3 columns
byte gauge_fill_4[8] = {B11111, B11110, B11110, B11110, B11110, B11110, B11110, B11111}; // filled gauge - 4 columns
byte gauge_fill_5[8] = {B11111, B11111, B11111, B11111, B11111, B11111, B11111, B11111}; // filled gauge - 5 columns
byte gauge_left[8] = {B11111, B10000, B10000, B10000, B10000, B10000, B10000, B11111}; // left part of gauge - empty
byte gauge_right[8] = {B11111, B00001, B00001, B00001, B00001, B00001, B00001, B11111}; // right part of gauge - empty
byte gauge_mask_left[8] = {B01111, B11111, B11111, B11111, B11111, B11111, B11111, B01111}; // mask for rounded corners for leftmost character
byte gauge_mask_right[8] = {B11110, B11111, B11111, B11111, B11111, B11111, B11111, B11110}; // mask for rounded corners for rightmost character
byte warning_icon[8] = {B00100, B00100, B01110, B01010, B11011, B11111, B11011, B11111}; // warning icon - just because we still have one custom character left
byte gauge_left_dynamic[8]; // left part of gauge dynamic - will be set in the loop function
byte gauge_right_dynamic[8]; // right part of gauge dynamic - will be set in the loop function
int cpu_gauge = 0; // value for the CPU gauge
char buffer[10]; // helper buffer to store C-style strings (generated with sprintf function)
int move_offset = 0; // used to shift bits for the custom characters
const int gauge_size_chars = 16; // width of the gauge in number of characters
char gauge_string[gauge_size_chars+1]; // string that will include all the gauge character to be printed
void setup()
{
lcd.init(); // initialize the 16x2 lcd module
lcd.createChar(7, gauge_empty); // middle empty gauge
lcd.createChar(1, gauge_fill_1); // filled gauge - 1 column
lcd.createChar(2, gauge_fill_2); // filled gauge - 2 columns
lcd.createChar(3, gauge_fill_3); // filled gauge - 3 columns
lcd.createChar(4, gauge_fill_4); // filled gauge - 4 columns
lcd.createChar(0, warning_icon); // warning icon - just because we have one more custom character that we could use
lcd.backlight(); // enable backlight for the LCD module
}
void loop()
{
float units_per_pixel = (gauge_size_chars*5.0)/100.0; // every character is 5px wide, we want to count from 0-100
int value_in_pixels = round(cpu_gauge * units_per_pixel); // cpu_gauge value converted to pixel width
int tip_position = 0; // 0= not set, 1=tip in first char, 2=tip in middle, 3=tip in last char
if (value_in_pixels < 5) {tip_position = 1;} // tip is inside the first character
else if (value_in_pixels > gauge_size_chars*5.0-5) {tip_position = 3;} // tip is inside the last character
else {tip_position = 2;} // tip is somewhere in the middle
move_offset = 4 - ((value_in_pixels-1) % 5); // value for offseting the pixels for the smooth filling
for (int i=0; i<8; i++) { // dynamically create left part of the gauge
if (tip_position == 1) {gauge_left_dynamic[i] = (gauge_fill_5[i] << move_offset) | gauge_left[i];} // tip on the first character
else {gauge_left_dynamic[i] = gauge_fill_5[i];} // tip not on the first character
gauge_left_dynamic[i] = gauge_left_dynamic[i] & gauge_mask_left[i]; // apply mask for rounded corners
}
for (int i=0; i<8; i++) { // dynamically create right part of the gauge
if (tip_position == 3) {gauge_right_dynamic[i] = (gauge_fill_5[i] << move_offset) | gauge_right[i];} // tip on the last character
else {gauge_right_dynamic[i] = gauge_right[i];} // tip not on the last character
gauge_right_dynamic[i] = gauge_right_dynamic[i] & gauge_mask_right[i]; // apply mask for rounded corners
}
lcd.createChar(5, gauge_left_dynamic); // create custom character for the left part of the gauge
lcd.createChar(6, gauge_right_dynamic); // create custom character for the right part of the gauge
for (int i=0; i<gauge_size_chars; i++) { // set all the characters for the gauge
if (i==0) {gauge_string[i] = byte(5);} // first character = custom left piece
else if (i==gauge_size_chars-1) {gauge_string[i] = byte(6);} // last character = custom right piece
else { // character in the middle, could be empty, tip or fill
if (value_in_pixels <= i*5) {gauge_string[i] = byte(7);} // empty character
else if (value_in_pixels > i*5 && value_in_pixels < (i+1)*5) {gauge_string[i] = byte(5-move_offset);} // tip
else {gauge_string[i] = byte(255);} // filled character
}
}
// gauge drawing
lcd.setCursor(0,0); // move cursor to top left
sprintf(buffer, "CPU:%3d%% ", cpu_gauge); // set a string as CPU: XX%, with the number always taking at least 3 character
lcd.print(buffer); // print the string on the display
lcd.write(byte(0)); // print warning character
lcd.setCursor(0,1); // move the cursor to the next line
lcd.print(gauge_string); // display the gauge
// increase the CPU value, set between 0-100
cpu_gauge = cpu_gauge +1;
if (cpu_gauge > 100) {cpu_gauge = 0;}
delay(102); // wait for a while - 100ms = update the screen 10x in a second
}