C++ files for an Arduino light kit to be used for the School of the Art Institute of Chicago's Art and Technology Department to teach the basics of hardware / code to undergraduate and graduate students in Jan Tichy's Public Light and Space.
- Download the whole repository using the green download or clone button.
- Open the whole folder in Arduino (make sure the folder that contains everything is called light_kit).
- You would only be writing code in the light_kit.ino file - the other files were written to make things a lot easier, and will be working their magic from behind the scenes.
(Also, if you are prompted to create a new folder, make sure both the .cpp and the .h file are in the same folder as the .ino file!)
Now for the code! We can go through it together... Your .ino file should look something like this, and will be the only file you should be writing in -
The // in code indicates a comment. I left these sprinkled in so y'all could have a better idea of whats happening, but the Arduino itself can't read them, so feel free to write your own notes in a similar fashion.
#include "helper_files.h"
#include <stdio.h>
// creates instance of an RGB LED based on the pin OUTPUT below (r, g, b)
RGB_LED led_1(3,5,6);
void setup() {
}
void loop() {
// call the LED you made by putting the led name and the method (action) attached to it
// should be like myLEDname.thisIsTheAction()
// pass in (red value, green value, blue value, delay time)
// if you pass in 0 as delay time, it will just set that color static without fade
led_1.fadeUpLedTo(0,0,100,50);
delay(50);
led_1.fadeDownLedFrom(0,0,100,100);
delay(50);
}lets go through this line by line...
Ignore the first two lines (below) - we don't need to worry about these... They're just letting the code know to use the two other files that are working the magic.
#include "helper_files.h"
#include <stdio.h>The next line (below) is important.
RGB_LED led_1(3,5,6);We are calling a class to create a new instance of RGB_LED that we are naming led_1 We are then passing in three pins (redpin, greenpin, bluepin).
A good metaphor for this would be to think about it like a recipe. In the .cpp files and the .h files, I wrote the recipe for an RGB_LED. In the .ino file, you are just calling the recipe, and adding in your own special sauce to customize your LED. You can say RGB_LED thisIsMySpecialLED(1,2,3) and it would create an RGB_LED called thisIsMySpecialLED that has its red pin as 1, its green pin as 2 and its blue pin as 3.
We can ignore the next lines (below) - we need this for more basic Arduino programming, but the magic for the setup are in the other files.
void setup() {
}Now for the real action! In the void loop(), this code repeats itself over and over again and is native to Arduino.
void loop() {
led_1.fadeUpLedTo(0,0,100,50);
delay(50);
led_1.fadeDownLedFrom(0,0,100,100);
delay(50);
}Remember the instance of RGB_LED we made above called led_1?
Now we are putting it into action.
We are calling our instance of RGB_LED by stating its name (led_1), and attaching the action (or method) we are trying to have it execute - its sort of like plain non-code-y English, we are telling led_1 to fade up to a color, and fade down from that color to black and to repeat.
Right now, we have the ability to use these methods:
.fadeUpLedTo(red_value, green_value, blue_value, delay_time);
delay(50);
.fadeDownLedFrom(red_value, green_value, blue_value, delay_time);
delay(50);And we are passing in four values to it. the first three stand for red, green and blue, and the last is for the delay time, or the amount of time it would take to fade up to the specific RGB color you have. If you wanted it to be instantaneous, pass in 0. The second delay is to keep it at whatever the previous color you faded up to or faded down from.
I will continue to add methods and write more documentation for the new ones!
The final result should be something like we see above, where we have -
thisIsMySpecialLED.fadeUpLedTo(red_value, green_value, blue_value, delay);
aaaaaand thats it!
Create more LEDs by repeating these steps and calling them in the void loop();
Feel free to submit questions through this, and I'll try my best to get back to you. :)
Happy coding!
-- Amanda
This is where the magic happens
Now we get into the more complicated things - if you have any changes, feel free to pull and push, and we can keep this as a live code base for PLS! If this is your first time coding, feel free to read over the below, but don't sweat it if it doesn't make sense...
There are two files that hold the class c'tor - so far I only have RGB and White lights in the repo, but I'll work on getting two LEDs to fade at the same time, LED strips, and whatever other light toys we want to use, so students can just create their own instance of the class with their own pins and names! Yay!
The helper_files.h tells whether the functions in the class are public or private.
I am declaring the class and functions as public, and the pins as private, so that we can pass in different values for the pins for only the class that we are constructing to reference. This way we can have two instances of the class with two different sets of pins!
The helper_files.cpp holds the meat of the function.
I am iterating up 3 pins simultaneously to get the RGB LED to fade to a specific color and time. We also have a function for white LEDs (digital and analog) for
futureLED kits. The while statement was the quick and dirty way to iterate three pins at once for RGB, and we can rethink this in the future!
Feel free to reach out with any updates / ways we can make this better - I'll be posting the circuitry diagrams and more info once we have finalized the physical kits.
© Amanda Yamasaki 2018