How to translate Arduino demos into BrickPixel demos
When looking for examples of lighting control using the Arduino, you will usually find code that uses the on-board LED as the light. The control logic in the code is what's needed, but how can that be translated to working with the BrickPixel Arduino shield?
The following shows what, at a minimum, needs to be added to Arduino demo examples to make them work with BrickPixel.
Here is an Arduino demo that comes with the Arduino IDE.
/* Blink without Delay Turns on and off a light emitting diode (LED) connected to a digital pin, without using the delay() function. This means that other code can run at the same time without being interrupted by the LED code. The circuit: - Use the onboard LED. - Note: Most Arduinos have an on-board LED you can control. On the UNO, MEGA and ZERO it is attached to digital pin 13, on MKR1000 on pin 6. LED_BUILTIN is set to the correct LED pin independent of which board is used. If you want to know what pin the on-board LED is connected to on your Arduino model, check the Technical Specs of your board at: https://www.arduino.cc/en/Main/Products created 2005 by David A. Mellis modified 8 Feb 2010 by Paul Stoffregen modified 11 Nov 2013 by Scott Fitzgerald modified 9 Jan 2017 by Arturo Guadalupi This example code is in the public domain. http://www.arduino.cc/en/Tutorial/BlinkWithoutDelay */ // constants won't change. Used here to set a pin number: const int ledPin = LED_BUILTIN;// the number of the LED pin // Variables will change: int ledState = LOW; // ledState used to set the LED // Generally, you should use "unsigned long" for variables that hold time // The value will quickly become too large for an int to store unsigned long previousMillis = 0; // will store last time LED was updated // constants won't change: const long interval = 1000; // interval at which to blink (milliseconds) void setup() { // set the digital pin as output: pinMode(ledPin, OUTPUT); } void loop() { // here is where you'd put code that needs to be running all the time. // check to see if it's time to blink the LED; that is, if the difference // between the current time and last time you blinked the LED is bigger than // the interval at which you want to blink the LED. unsigned long currentMillis = millis(); if (currentMillis - previousMillis >= interval) { // save the last time you blinked the LED previousMillis = currentMillis; // if the LED is off turn it on and vice-versa: if (ledState == LOW) { ledState = HIGH; } else { ledState = LOW; } // set the LED with the ledState of the variable: digitalWrite(ledPin, ledState); } }
This is an altered version that adds what is needed by the BrickPixel system. This example keeps everything in the original program, so the Arduino on-board LED will work as before, with the addition of the first pixel (or LED) in the BrickPixel light string replicating what the on-board LED is doing.
/* Blink without Delay with added BrickPixel commands */ // library for controlling the BrickPixel hardware (REQUIRED) #include <Adafruit_NeoPixel.h> // constants won't change. Used here to set a pin number: const int ledPin = LED_BUILTIN;// the number of the LED pin // The BrickPixel equivalent of ledPin Adafruit_NeoPixel pixels(1, 7, NEO_RGB + NEO_KHZ800); // Variables will change: int ledState = LOW; // ledState used to set the LED // Generally, you should use "unsigned long" for variables that hold time // The value will quickly become too large for an int to store unsigned long previousMillis = 0; // will store last time LED was updated // constants won't change: const long interval = 1000; // interval at which to blink (milliseconds) void setup() { // set the digital pin as output: pinMode(ledPin, OUTPUT); // Initialize the NeoPixel object (this is REQUIRED) pixels.begin(); // Clear out any prior BrickPixel settings pixels.clear(); } void loop() { // here is where you'd put code that needs to be running all the time. // check to see if it's time to blink the LED; that is, if the difference // between the current time and last time you blinked the LED is bigger than // the interval at which you want to blink the LED. unsigned long currentMillis = millis(); if (currentMillis - previousMillis >= interval) { // save the last time you blinked the LED previousMillis = currentMillis; // if the LED is off turn it on and vice-versa: if (ledState == LOW) { ledState = HIGH; // the equivalent of ledState HIGH pixels.setPixelColor( 0, pixels.Color(255, 0, 0) ); } else { ledState = LOW; // the equivalent of ledState LOW pixels.setPixelColor( 0, pixels.Color(0, 0, 0) ); } // set the LED with the ledState of the variable: digitalWrite(ledPin, ledState); // set the pixel with the pixelState pixels.show(); } }
The changes [listed in bold above] are:
- Adding the Adafruit library that allow control of the BrickPixel system
- Creating an equivalent BrickPixel LED address to send the control commands to
- Setting up the BrickPixel to be ready for control commands
- Setting the BrickPixel LED to maximum brightness (HIGH state) or minimum brightness (LOW state)
- Sending the updated LED state to the BrickPixel
Sometimes you might see the reference to the LED output address on the Arduino as pinMode(LED_BUILTIN, OUTPUT); or pinMode(9, OUTPUT); instead of the combination used the Arduino demo program above.
// constants won't change. Used here to set a pin number: const int ledPin = LED_BUILTIN;// the number of the LED pin . . . // set the digital pin as output: pinMode(ledPin, OUTPUT);
This won't change what is added to have the BrickPixel work.
If you have any problems, questions, comments or suggestions, post'em here or PM me.
-wrtyler-