Tuesday, April 16, 2013

Power LED bike tail light with Arduino control

I needed a new bike light and I went about looking at off the shelf ones but what I wanted wasn't available. At least not all in the same light. SO like usual I decided to build my own. I'm going to write up an instructable on this since it is rather complex but I used two 1watt power LEDs inside the hollowed out shell of an old cheapy rear bike light I had. I then put the ardunio controller along with two separate MOSFET circuits as a current limiters for each LED (a lot of credit goes to Dan Goldwater for his excellent instructable on High Power LED drivers), then added a LiPo battery and built in charger and one button all to an altoids tin. Here is an early video of the prototype.


 The board laid out ready to be fitted to the Altoids tin

 LEDs mounted with lenses to the old light housing

 The charger port gets hidden when the top is closed.




Here is it in daylight from across the street.


 All done and working!


Oh and I'm still able to program it since I added in a header for my FTDI cable.

UPDATE: Here is the full schematic, note Circuit labs doesn't have a decent facsimile to the TMP36 analog temperature sensor so i just used a Pot, kind of the same functionality when you think about it. just different input.



I'll be the first to admit that the code here is not the best. The debug function is nasty but serves a purpose and keeps things (in my mind) a bit cleaner and allows me to having different logging levels during troubleshooting. Now that the code is well tested I could probably remove it all but I'll bet it would mess up all my timing since the serial prints won't be there.  I'll work on making schematics for the wiring, since right now it is mostly in my head or on a whiteboard. Anyway here's the code.

UPDATE: New Code for Rear Bike Light --> I've made a new post with all the serial debugging removed. It is cleaner but I'm still not sure about the timing and that is mostly to do with the button press durations. That is where a huge majority of my debugging was so the difference between a "long" press and a "short" one will be drastically quicker. I'll test this some time soon.


/*--------------------------------------------------------
Rear Bike Light Project                                    
Author: Chris Crumpacker                               
Date: October 2012 

Copyright (c) 2012 Chris Crumpacker.  All right reserved.

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.
                                                           
Sketch Notes: This version contains 6 modes of blinking with 
multiple speeds for some modes. This works off of a single 
button, with short presses the program steps thru the 
modes/speeds. When long pressed it goes into a "sleep" 
mode where the high powered LEDs are turned off. 
It also has the ablity to store the current mode so when 
leaving sleep mode or being brought back up from a power 
down it will return to the previous mode it was in. 
There is also an interal tempurature sensor that will 
put it into a hidden (at least from the mode scrolling) 
"limp home mode" during a certain temp range or evenshut the 
LEDs down if it gets any higher.
--------------------------------------------------------*/

//-------------------------
// Includes
//-------------------------
#include 
#include 

//-------------------------
// Defines
//-------------------------
#define BUTTON_PIN       11                                                  // Button

#define LONGPRESS_LEN    10                                                  // Min numberr of loops for a long press
#define DELAY            10                                                  // Delay per loop in ms
#define CONFIG_VERSION   "rbl1"                                              // ID of the settings block
#define memoryBase       32                                                  // Tell it where to store your config data in EEPROM                                                          //Constructor for the Simple Timer

enum { EV_NONE=0, EV_SHORTPRESS, EV_LONGPRESS };

//-------------------------
// Pin Assignment
//-------------------------
int ledPinl = 9;                                                             // Left LED
int ledPinr = 10;                                                            // Right LED
int powerPin = 13;                                                           // Case LED to show that the circuit has power
int tempSensorPin= A5;                                                       // Analog pin the case's Temp36 sensor is on

//-------------------------
// Variables
//-------------------------
boolean ok = true;                                                           // bool for the EEPROM's config setup
int configAdress = 0;

boolean currentButton = LOW;
boolean button_was_pressed = false;
int previousButton;
int button_pressed_counter = 0;
int longPress = LONGPRESS_LEN;
int buttonCount = 0;
long previousMillis = 0;

boolean fromCheckTemp = false;
long previousTempTime = 0;
float tempLimp = 100;                                                         // In degrees (f)
float tempShutdown = 120;                                                     // In degrees (f)
int checkTempInterval = 30000;                                                // In Milliseconds

float freq;
float freqInitial = .002;
float freqChange = .002;
float freqLimit = .006;

int ledStep = 255;                                                            // How much to change the dimming (PWM) between each step for steps 6 to 9 and 10 to 13

int ledState = HIGH;
int debugLevel = 1;                                                           // 0 = off, 1 = low, 2 = high, 3 = verbose

// The struct for the config saved to the EEPROM
struct StoreStruct {
    char* cVersion;                                                          // This is to detect if the settings stored in the EEPROM are for this config and sketch
    int bc;
} storage = { 
    CONFIG_VERSION,                                                          // Defaults
    0
};

//-------------------------
// Setup
//-------------------------
void setup() {
  Serial.begin(9600);                                                        // Sets up the serial port and speed
  pinMode(BUTTON_PIN, INPUT);                                                // Setting the button pin to an input
  digitalWrite(BUTTON_PIN, HIGH);                                            // Setting the button with a pull-up resistor, the button when grounded or "low" will be thought of as pressed
  pinMode(powerPin, OUTPUT);                                                 // Setting the pin for the LED on the board to show that power is on or will blink if in a sleep mode
  pinMode(ledPinl, OUTPUT);                                                  // External LED control pin 1
  pinMode(ledPinr, OUTPUT);                                                  // External LED control pin 2
  EEPROM.setMemPool(memoryBase, EEPROMSizeATmega328);                        // Set memorypool base to 32, assume Atmega328
  configAdress = EEPROM.getAddress(sizeof(StoreStruct));                     // Size of config object 
  ok = loadConfig();                                                         // Loads the config, and if it loads sets the bool "ok" to true
  buttonCount = storage.bc;                                                  // Sets the variable for the buttonCount to what is brought back from the storage
  checkTemp("setup");                                                        // Checks the intial temp at start up
  freq = setFreq("setup");                                                   // Sets the initial Frequency for the pulsing modes
  ledStep = setLEDStep("setup");                                             // Sets the initial LED PWM step value for the dimming modes
  digitalWrite(powerPin, ledState);                                          // Turns on the on board LED  
}

//-------------------------
// Functions
//-------------------------

// Debug Function
/*
This function allows you to print valuable information from within each function.
For each function that calls the debug you first need to set 
"debugFuncName" variable first for example:  
  char* debugFuncName = "xyzFunction";

Now the function name is just a string so you can make it whatever you like but for
consistancy I keep it the name of the function it's self. Now any time a new variable is set 
you can call the debug to print it to the serial monitor like so:
  debug(variable,"human readable yet short variable description",debugFuncName,fromFunc);
  
The "fromFunc" part is needed when your base function is calling anothering function to do work.
For example if you have multiple functions that repeat but you check a global button state monitor
you would want to know that the variable is being set in the button monitor on behalf of each 
particular function. 

When calling the button monitor from each function I would pass 
the debugFuncName variable like this:
  buttonMonitor(debugFuncName);
  
In that button monitor the sending fuction name variable is passed in like this:
  void buttonMonitor(char* fromFunc){...}
  
If you don't intend to do this nested funtion calling you can remove the last part of the debug
function decleration. or if just one debug trace doesn't need it you can just use an empty set like this:
  debug(variable,"human readable yet short variable description",debugFuncName,"");
*/
void debug(int msgLevel,float variable, char* message, char* inFunc, char* fromWhere){
  boolean printToSerial;
  
  if (debugLevel == 3 && (msgLevel == 3 || msgLevel == 2 || msgLevel == 1)){
    //Verbose logging
    printToSerial = true;
  } else if (debugLevel == 2 && (msgLevel == 2 || msgLevel == 1)) {
    //High logging
    printToSerial = true;    
  }else if (debugLevel == 1 && msgLevel == 1) {
    //Low logging
    printToSerial = true;
  } else if (debugLevel == 0) {
    //Debugging disabled
    printToSerial = false;
  } else {
    //Debug level not high enough to trace out to serial
    printToSerial = false;
  }
  /*If the debug level is high enough for the msgLevel of the debug trace
  it will be printed to serial if not it will be ignored*/ 
  if (printToSerial == true) {
    Serial.print(variable); 
    Serial.print(" ");
    Serial.print(message); 
    Serial.print(" in "); 
    Serial.print(inFunc); 
    Serial.print(" from "); 
    Serial.println(fromWhere);
  }
}
    
// Loads the Config from EEPROM
bool loadConfig() {                                             
  EEPROM.readBlock(configAdress, storage);
  return (storage.cVersion == CONFIG_VERSION);
}

// Saves Config changes to the EEPROM
void saveConfig() {                                              
   EEPROM.writeBlock(configAdress, storage);
}

//--Button Handling--
// This function determines if the button press is short or long and is made to report back to a switch case
void handle_button(int longPress, char* fromFunc,int modeType)
{
  char* debugFuncName = "handle_button";
  int button_now_pressed = !digitalRead(BUTTON_PIN);                         // pin low -> pressed
  
  if (!button_now_pressed && button_was_pressed) {
//Short press
    if (button_pressed_counter < longPress) { 
        debug(1,buttonCount,"Short Pressed",debugFuncName,fromFunc);
        debug(2,freq*100,"Frequence",debugFuncName,fromFunc);
        debug(2,ledStep,"LED step value",debugFuncName,fromFunc);
        debug(2,buttonCount,"buttonCount",debugFuncName,fromFunc);
        debug(1,button_pressed_counter,"Cycles - Button was Pressed for this many cycles",debugFuncName,fromFunc);
        if (modeType == 1){
          /*Short press from one of the pulsing modes. This increments the button count, 
          updates the Frequency and possibly the LEDStep and also stores the new buttonCount away in the EEPROM*/
          previousButton = buttonCount;
          debug(2,previousButton,"PreviousButton should now be set to old button count",debugFuncName,fromFunc);
          ++buttonCount;
          debug(2,buttonCount,"buttonCount incremented by 1",debugFuncName,fromFunc);
          storage.bc = buttonCount;
          saveConfig();
          setFreq(debugFuncName);
          setLEDStep(debugFuncName);
          debug(1,storage.bc,"storage.bc of buttonCount via short press",debugFuncName,fromFunc);
          debug(1,buttonCount,"------------------------------------------------------",debugFuncName,fromFunc);
        } else if (modeType == 2){
          /*Short press from one of the dimming PWM modes. This increments the button count, 
          updates the Frequency and the LEDStep and also stores the new buttonCount away in the EEPROM*/
          previousButton = buttonCount;
          debug(2,previousButton,"PreviousButton should now be set to old button count",debugFuncName,fromFunc);
          ++buttonCount; 
          debug(2,buttonCount,"buttonCount incremented by 1",debugFuncName,fromFunc);
          storage.bc = buttonCount;
          saveConfig(); 
          setFreq(debugFuncName);
          setLEDStep(debugFuncName); 
          debug(1,storage.bc,"storage.bc of buttonCount via short press",debugFuncName,fromFunc);
          debug(1,buttonCount,"------------------------------------------------------",debugFuncName,fromFunc);
        } else if (modeType == 3) { 
          /*Short press for the sleep modes 14 and 15. This starts us back to the first mode (0) and sets 
          the frequency and the LED step as well as store the button count to the EEPROM*/      
          debug(1,buttonCount,"Short button press",debugFuncName,fromFunc);
          buttonCount = 0;
          debug(2,buttonCount,"buttonCount should now be 0",debugFuncName,fromFunc);
          storage.bc = buttonCount;                                  //Stores the buttonCount to EEPROM
          saveConfig();
          debug(1,storage.bc,"storage.bc of buttonCount via Short press",debugFuncName,fromFunc);
          setFreq(debugFuncName); 
          setLEDStep(debugFuncName);
          fromCheckTemp = false;
          debug(1,buttonCount,"------------------------------------------------------",debugFuncName,fromFunc); 
        }
//Long Press
    } else { 
        debug(1,buttonCount,"Long Press",debugFuncName,fromFunc);
        debug(1,button_pressed_counter,"Cycles - Button was Pressed for this many cycles",debugFuncName,fromFunc);
        if (modeType == 1 || modeType == 2){
          /*Long press for any of the "awake" modes. It puts the external LEDs to sleep in mode 14 or sleep mode. 
          Also it sets the previous button so when exiting the sleep mode it knows what to go back to*/
          previousButton = buttonCount;                              
          buttonCount = 14;
          debug(2,previousButton,"previous buttonCount",debugFuncName,fromFunc);
          debug(2,buttonCount,"new buttonCount should be 14 for Sleep",debugFuncName,fromFunc); 
          debug(1,buttonCount,"------------------------------------------------------",debugFuncName,fromFunc);
        } else if (modeType == 3) {   
          /*Long press from one of the sleep modes. This sets the button count back to the previous button, 
          updates the Frequency and the LEDStep and also stores the new buttonCount away in the EEPROM*/ 
          buttonCount = previousButton;
          debug(2,previousButton,"previous button",debugFuncName,fromFunc);
          debug(2,buttonCount,"buttonCount now should be set to previous button",debugFuncName,fromFunc);
          storage.bc = buttonCount; 
          saveConfig();
          setFreq(debugFuncName); 
          setLEDStep(debugFuncName);
          debug(1,storage.bc,"storage.bc of buttonCount via Long press",debugFuncName,fromFunc);
          debug(1,buttonCount,"------------------------------------------------------",debugFuncName,fromFunc);
          fromCheckTemp = false;
        }
    }
//No Press
  } else {
    debug(3,buttonCount,"No button was pressed",debugFuncName,fromFunc);
  }

  if (button_now_pressed)
    ++button_pressed_counter;
  else
    button_pressed_counter = 0;
    debug(3,button_pressed_counter,"--Button Pressed Counter--",debugFuncName,fromFunc);
    
  button_was_pressed = button_now_pressed;
}

//Checks the tempurature inside the circuit enclosure, 
void checkTemp(char* fromFunc) {
  char* debugFuncName = "checkTemp";
  unsigned long currentTempTime = millis();                                  // Set the current time
  if(currentTempTime - previousTempTime > 20000){
    previousTempTime = currentTempTime;
    float Vcc = readVcc();                                                   // Calculating the Supply Voltage
    Vcc = Vcc / 1000;                                                        // Converting from mV to Volts
    debug(3,Vcc,"Vcc in V",debugFuncName,fromFunc);
    int reading = analogRead(tempSensorPin);                                 // Reading the voltage from the sensor pin
    debug(3,reading,"Temp_Sensor_Pin_Reading",debugFuncName,fromFunc);
      
//  Converting that reading to voltage
    float voltage = reading * Vcc;
    voltage /= 1024.0; 
    debug(3,voltage,"reading Voltage converted",debugFuncName,fromFunc);
    
//  Print out the temperature in Celcius
    float temperatureC = (voltage - 0.5) * 100 ;                    //converting from 10 mv per degree wit 500 mV offset to degrees ((volatge - 500mV) times 100)
    debug(2,temperatureC,"temp in C",debugFuncName,fromFunc);
    
//  Now convert to Fahrenheight
    float temperatureF = (temperatureC * 9.0 / 5.0) + 32.0;
    debug(1,temperatureF,"temp in F",debugFuncName,fromFunc);
     
    if (temperatureF > tempLimp && temperatureF < tempShutdown) {
      buttonCount = 15;
      fromCheckTemp = true;
      debug(1,buttonCount,"Open a window! it's getting stuffy. I'll turn the lights down",debugFuncName,fromFunc);
    } else if (temperatureF >= tempShutdown && buttonCount != 14) {
      buttonCount = 14;
      fromCheckTemp = true;
      debug(1,buttonCount,"It's getting Hot in here, so take off all your clothes. I'll shut down the lights in the mean time",debugFuncName,fromFunc);
    } else if (fromCheckTemp) {
      fromCheckTemp = false;
      buttonCount = previousButton;
      debug(2,buttonCount,"buttonCount set back to previous",debugFuncName,fromFunc);
      debug(1,buttonCount,"Awwww yeahhhh! It's business time.",debugFuncName,fromFunc);
    } else {
      fromCheckTemp = false;
      debug(1,buttonCount,"Awwww yeahhhh! It's business time.",debugFuncName,fromFunc);
    }
    debug(1,buttonCount,"------------------------------------------------------",debugFuncName,fromFunc);
  } else {
    //Holder for stuff to do while waiting on the time to check temp again
  }
debug(3,buttonCount,"------------------------------------------------------",debugFuncName,fromFunc);  
}

//When starting up with a stored button count we need to find and set the appropriate Frequency "freq" for the button count
float setFreq(char* fromFunc) {
  char* debugFuncName = "setFreq";
  debug(3,buttonCount,"Setting Frequency",debugFuncName,fromFunc);  
  if (buttonCount == 0 || buttonCount == 3) {
    freq = freqInitial;
  } 
  else if (buttonCount == 1 || buttonCount == 4) {
    freq = freqInitial + freqChange;
  } 
  else if (buttonCount == 2 || buttonCount == 5) {
    freq = freqInitial + freqChange + freqChange;
  }
  else {
    freq = freqInitial;
  }
  debug(3,freq*100,"Frequency set to",debugFuncName,fromFunc); 
  debug(3,buttonCount,"------------------------------------------------------",debugFuncName,fromFunc);
  return freq;
}

//When starting up with a stored button count we need to find and set the appropriate LED brightness "ledStep" for the button count
int setLEDStep(char* fromFunc) {
  char* debugFuncName = "setLEDStep";
  debug(3,buttonCount,"Setting LEDStep",debugFuncName,fromFunc);   
  if (buttonCount == 6 || buttonCount == 10){
    ledStep = 255;
  } 
  else if (buttonCount == 7 || buttonCount == 11) {
    ledStep = 191;
  } 
  else if (buttonCount == 8 || buttonCount == 12) {
    ledStep = 127;
  } 
  else if (buttonCount == 9 || buttonCount == 13) {
    ledStep = 64;
  }
  else {
    ledStep = 255;
  }
  debug(3,ledStep,"LED Step value",debugFuncName,fromFunc);
  debug(3,buttonCount,"------------------------------------------------------",debugFuncName,fromFunc);
  return ledStep;
}

//***************************//
//******Blinking Modes*******//
//***************************//

//"bothFlipFlopPulse" The LEDs pulse back and forth (3 speeds)
void bothFlipFlopPulse() {
  char* debugFuncName = "bothFlipFlopPulse";
  float ledIn;
  float ledOutL;
  float ledOutR;
  longPress = 10;
  debug(3,buttonCount,"buttonCount ",debugFuncName,"");
  checkTemp(debugFuncName);
  setFreq(debugFuncName);  
  for (ledIn = 4.712; ledIn < 10.995; ledIn = ledIn + freq)      // This sets the start of the LED (ledOutL) pulse on the sin wave to the first zero crossing 4.712 and ends it on the next 10.995.
    {
      ledOutL = sin(ledIn) * 127.5 + 127.5;                      // Making the sin wave all positive numbers and setting it to a scale of 0-255 for the PWM range
      ledOutR = 255 - (sin(ledIn) * 127.5 + 127.5);              // This inverts ledOutR so it pulses to the high as ledOutR pulses to the low
      analogWrite(ledPinl, ledOutL);
      analogWrite(ledPinr, ledOutR);
    }
    
    handle_button(longPress,debugFuncName,1);                    // Sets the Button function to run and read the button state, then returns the event, EV_SHORT, EV_LONG, or EV_NONE    
}

//"bothPulse" Like "bothFlipFlopPulse" but with both LEDs on the same sin wave (3 speed)
void bothPulse() {
  char* debugFuncName = "bothPulse";
  float ledIn;
  float ledOutL;
  float ledOutR;
  longPress = 10;
  checkTemp(debugFuncName);
  setFreq(debugFuncName);  
  for (ledIn = 4.712; ledIn < 10.995; ledIn = ledIn + freq)      //This sets the start of the LED (ledOutL) pulse on the sin wave to the first zero crossing 4.712 and ends it on the next 10.995.
    {
      int out = sin(ledIn) * 127.5 + 127.5;                      //Both LEDs will follow the sin wave but we also have to make it all positive numbers and set to a scale of 0-255 for the PWM range
      analogWrite(ledPinl, out);
      analogWrite(ledPinr, out);
    }
    
  handle_button(longPress,debugFuncName,1);
}

//"bothStepped" - Both LEDs on, stepping down the brightness with each button press (4 settings from full bright to rather dim)
void bothStepped() {
  char* debugFuncName = "bothStepped";
  longPress = 75;
  checkTemp(debugFuncName);
  setLEDStep(debugFuncName);
  analogWrite(ledPinl, ledStep);                                //Turns them both on together 
  analogWrite(ledPinr, ledStep);
  
  handle_button(longPress,debugFuncName,2);
  delay(DELAY);
}

//"singleStepped" - Just one LED on, stepping down the brightness with each button press (4 settings from full bright to rather dim)
void singleStepped(){
  char* debugFuncName = "singleStepped";
  debug(3,buttonCount,"button Count",debugFuncName,"");
  longPress = 75;
  checkTemp(debugFuncName);
  setLEDStep(debugFuncName);
  analogWrite(ledPinl, ledStep);
  digitalWrite(ledPinr, LOW);
    
  handle_button(longPress,debugFuncName,2);
  delay(DELAY);
}

//"sleep" external LEDs off but blink the power led on the circuit board.
void sleep() {
  char* debugFuncName = "sleep";
  longPress = 75;
  debug(3,fromCheckTemp," = From Check Temp",debugFuncName,"");                      
  checkTemp(debugFuncName);
  digitalWrite(ledPinl, LOW);                                    //Turns off both High Power LEDs
  digitalWrite(ledPinr, LOW); 
  
  // Blinks the powerPin light by checking the current time vs. the last time it went thru, once it is over the 1000 ms limit it changes the light's state
  unsigned long currentMillis = millis();
  if(currentMillis - previousMillis > 1000){
    previousMillis = currentMillis;
    if (ledState == LOW){
      ledState = HIGH;
    }
    else {
      ledState = LOW;
    }
    digitalWrite(powerPin, ledState);
  }
      
  handle_button(longPress,debugFuncName,3); 
  delay(DELAY);    
}

//"limpHome" The limp home mode, Like mode 1 the LEDs pulse back and forth, But slowly and only to half brightness.
void limpHome() {
  char* debugFuncName = "limpHome";
  float ledIn;
  float ledOutL;
  float ledOutR;
  debug(3,fromCheckTemp," = From Check Temp",debugFuncName,"");
  checkTemp(debugFuncName);
  longPress = 75;
  for (ledIn = 4.712; ledIn < 10.995; ledIn = ledIn + .002)      // This sets the start of the LED (ledOutL) pulse on the sin wave to the first zero crossing 4.712 and ends it on the next 10.995.
    {
      ledOutL = sin(ledIn) * 100 + 127.5;                        // Making the sin wave all positive numbers and setting it to a scale of 0-255 for the PWM range
      ledOutR = 255 - (sin(ledIn) * 127.5 + 127.5);              // This inverts ledOutR so it pulses to the high as ledOutR pulses to the low
      analogWrite(ledPinl, ledOutL);
      analogWrite(ledPinr, ledOutR);
    }
    
  unsigned long currentMillis = millis();
  if(currentMillis - previousMillis > 1000){
    previousMillis = currentMillis;
    
    if (ledState == LOW){
      ledState = HIGH;
    }
    else {
      ledState = LOW;
    }
    digitalWrite(powerPin, ledState);
  }
    
  handle_button(longPress,debugFuncName,3);
  delay(DELAY); 
}

//-------------------------
// THE LOOP
//-------------------------
void loop()
{
  char* debugFuncName = "loop";
  
  //Set what mode the LEDs are in based on how many times the button is pressed.
  while (buttonCount < 3)
  {
    bothFlipFlopPulse();
  }
  while (buttonCount >= 3 && buttonCount < 6)
  {
    bothPulse();
  }
  while (buttonCount >= 6 && buttonCount < 10)
  {
    bothStepped();
  }
  while (buttonCount >= 10 && buttonCount < 14)
  {
    singleStepped();
  }
  while (buttonCount == 14)
  {
    sleep(); 
  }
  while (buttonCount == 15)
  {
    limpHome(); 
  }
  delay(DELAY);
}

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