Lightino Lessons Help Sheet

The Basics

  • Statements are grouped together by curly brackets { }, not by indentation (as in Python).
  • You can put newlines and spaces where you like, but your code will be easier to read if you indent it (like Python).
  • Everything between // and the end of the line, or between /* and */ is a comment.
  • All variables must be declared, defining their type. They have no meaning outside the smallest enclosing { }. Declarations must be the first things after {.
  • All statements (including declarations) must be terminated by a semicolon.
  • Lines beginning with # are definitions of constants or directives to include a file from somewhere else containing stuff you'll be needing.


int a, b, c; // Declare 3 integers

float x; // Declare a floating point variable (needn't be a whole number)

boolean love_marmite; // Takes the values true or false

char c; // this variable holds a single character

int blindmouse[3]; // declares blindmouse[0], blindmouse[1] and blindmouse[2]


See the Arduino Reference (under Help in the Arduino IDE) for a list of operators.


x = (a + b) / c;


if ( a == 0 ) then { ….}

if (x >= 0 && x < 10} then { …. } else { …. }


while ( sum < max ) do { …. }

for (i=0; i<10; i++) { ….} // The same as i = 0; while (i < 10) { ….; i = i+1; }

break; // Exit immediately from the smallest surrounding loop

continue; // Go back to the top of the smallest surrounding loop and start the next time round.


  • A function has a type, but if it just does a job and doesn't return anything the type is void.
  • We have to declare the type of the parameters (length and breadth), to which are assigned the values given in the function call.
  • See the Arduino Reference for standard functions you can use.

float area(float length, float breadth) {

 return length * breadth;


roomsize = area(6, 9);

Previous article Addressable LED Strips - Common Questions

Check out our latest products...

A-Star 32U4 Prime LV with microSD - Derivative Boards

A-Star 32U4 Prime LV with microSD

£31.00 inc VAT
£25.83 ex VAT
A-Star 32U4 Prime LV - Derivative Boards

A-Star 32U4 Prime LV

£25.99 inc VAT
£21.66 ex VAT
TFT LCD Breakout - 1.8 (128x160) (LCD-15143) - LCD Displays
Qwiic Scale - NAU7802 (SEN-15242) - Sensor

Qwiic Scale - NAU7802 (SEN-15242)

£13.99 inc VAT
£11.66 ex VAT
VEML7700 Lux Sensor - I2C Light Sensor (ID:4262) - Visible Light
Grove Base Kit for Raspberry Pi - Grove

Grove Base Kit for Raspberry Pi

£34.00 inc VAT
£28.33 ex VAT
RF Explorer Signal Generator COMBO - Other

RF Explorer Signal Generator COMBO

£337.99 inc VAT
£281.66 ex VAT
Grove - 10A DC Current Sensor (ACS725) - Grove

Grove - 10A DC Current Sensor (ACS725)

£10.00 inc VAT
£8.33 ex VAT