195 lines
5.5 KiB

/* Bike Computer V1.1 - with diagnostics
Using the serial functions signifigantly increases compiled size, use this if you have a problem in execution or are testing.
Use the version without diagnostics in production (once you work out the bugs of course)
Provides controls to basic functions on a bike, such as turning on and off lights,
Measuring distance traveled, average speed, and logs to a microSD card.
Future versions will also be able to communicate to other
microcontrollers through the serial interface.
Version 1 (This version) will be responsible for detecting ambiant light and ramping
up/down the front and rear LED brightness once light levels reach a certain level.
Other responsibilities will be blinking pairs of LEDs (front and back) on either side
of the bike to indicate turning.
#include <SoftwareSerial.h>
SoftwareSerial lcd(2, 8); // This is required, to start an instance of an LCD
const int dispSw = A3;
// D4 and D5 are reserved for I2C
// Headlight
const int ambientIn = A0; // Analog input pin that the potentiometer is attached to
const int headlight = 3; // Digital output pin that the LED is attached to
const int incrBy = 5; // Amount to increase or decrease LED brightness by
int sensorValue = 0; // value read from the pot
int outputValue = 0; // value output to the PWM (analog out)
// Blinkers
const int lBnkSw = A1; // Left Blinker switch
const int rBnkSw = A2; // Right Blinker switch
const int lBnk = 6; // Left Blinker
const int rBnk = 7; // Right Blinker
const int bnkSpeed = 500; // in ms, 500 = twice a second
int lBnkSt = LOW;
int rBnkSt = LOW;
int lBnkSwSt = 0;
int rBnkSwSt = 0;
unsigned long previousMillis = 0;
void setup() {
lcd.begin(9600); // Start the LCD at 9600 baud
clearDisplay(); // Clear the display
// initialize serial communications at 9600 bps:
Serial.println("Loading bike computer diagnostics.");
Serial.println("This computer will log output to the console in the format: key = value\t key = value");
// Set out outputs
Serial.println("Setting our output pins");
pinMode(headlight, OUTPUT);
pinMode(lBnk, OUTPUT);
pinMode(rBnk, OUTPUT);
// Set our inputs
Serial.println("Setting our input pins");
pinMode(ambientIn, INPUT);
pinMode(lBnkSw, INPUT);
pinMode(rBnkSw, INPUT);
pinMode(dispSw, INPUT);
lcd.print(" BCPU");
lcd.print("Bike Computer");
Serial.println("Let the games begin!");
void echo(String key, String value){ // This function logs all information to the console and saves on space without having to repeat itself
Serial.print(" = ");
void headLight(){ // Main function for determining whether or not to ramp up or ramp down the headlight and taillight. Uses ambient light sensor for that
sensorValue = analogRead(ambientIn);
if(sensorValue <= 45 && outputValue <= 250){
outputValue = outputValue + incrBy;
if(sensorValue >= 50 && outputValue > 0){
outputValue = outputValue - incrBy;
analogWrite(headlight, outputValue);
if(outputValue >= 20){ // Ramp up/down lcd brightness with headlight - anything lower than 20 is too hard to read
lcd.print("*"); // Headlight indicator on lcd
lcd.print(outputValue); // Brightness level of headlight
echo("Ambient", String(sensorValue));
echo("Headlight", String(outputValue));
void blinker(){ // Controls the blinkers
unsigned long currentMillis = millis();
// Get info from switches
lBnkSwSt = digitalRead(lBnkSw);
rBnkSwSt = digitalRead(rBnkSw);
// Automatically turn off LEDs if switch is off
if(lBnkSwSt == LOW){ digitalWrite(lBnk, LOW); }
if(rBnkSwSt == LOW){ digitalWrite(rBnk, LOW); }
if(lBnkSwSt == HIGH){ // Test if left blinker switch is on
echo("lBlinkSw", "ON");
if(currentMillis - previousMillis >= bnkSpeed){
previousMillis = currentMillis;
if(lBnkSt == LOW){
lBnkSt = HIGH;
echo("lBlinker", "ON");
lBnkSt = LOW;
lcd.print(" ");
echo("lBlinker", "OFF");
digitalWrite(lBnk, lBnkSt); // Begin blinking
if(rBnkSwSt == HIGH){ // Test if right blinker is on
echo("rBlinkSw", "ON");
if(currentMillis - previousMillis >= bnkSpeed){
previousMillis = currentMillis;
if(rBnkSt == LOW){
rBnkSt = HIGH;
echo("rBlinker", "ON");
rBnkSt = LOW;
lcd.print(" ");
echo("rBlinker", "OFF");
digitalWrite(rBnk, rBnkSt); // Begin blinking
void setBacklight(byte brightness){
lcd.write(0x80); // send the backlight command
lcd.write(brightness); // send the brightness value
void clearDisplay(){
lcd.write(0xFE); // send the special command
lcd.write(0x01); // send the clear screen command
void setLCDCursor(byte cursor_position){
lcd.write(0xFE); // send the special command
lcd.write(0x80); // send the set cursor command
lcd.write(cursor_position); // send the cursor position
void loop(){
lcd.print("MPH: 7.5");
// End of secondary functions, append new line to console