Bike POV Bytes Beta 1
From Open Source Urbanism
Code for the Arduino Bike POV project, Byte version
Version: B1.0
Status: not working (due to memory problems)
(use the font.h code from Bike_POV_Beta_4)
//============================================================ // Bike POV Bytes // // by Scott Mitchell // www.openobject.org // Open Source Urbanism // // Copyright (C) 2008 Scott Mitchell 12-10-2008 // // This program is free software: you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // This program 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 General Public License for more details. // // A copy of the GNU General Public License // can be found at <http://www.gnu.org/licenses/>. // // B1.0 // Last Modified: October 16, 2008 //============================================================ #undef int() // fixes a bug with the stdio.h #include <stdio.h> // gives access to function sprintf // defining the alphabet #include "font.h" // define the Arduino LED pins in use const unsigned int LEDpins[] = { 1,2,3,4,5,6,7}; // number of LEDs const unsigned int charHeight = sizeof(LEDpins); const unsigned int charWidth = 5; // set up display parameters const unsigned int numFrames = 350; // number of frames per rotation unsigned long frameDuration = 1000; // time for each frame in microseconds - updated from rotation speed const unsigned int letterSpace = 4; // number of frames between letters const unsigned int stringSpace = 10; // number of frames between text string repeat unsigned long startTime = (millis() * 1000); // start time for wheel rotation in microseconds unsigned int byteNum = 0; // the byte being displayed // sensor setup const unsigned int sensorPIN = 0; // define the Arduino sensor pin const unsigned int mean = 508; // sensor at rest (no magnet) const unsigned int sensitivity = 30; // sensor sensitivity // distance and speed variables (floats are avoided because they slow the Arduino down) unsigned long numWheelRotations; // the base from which all other data is calculated const unsigned long wheelCurcum = 1100; // bike wheel circumfrance in mm (adjust this to match your bike) // text string byte byteString[200]; // the text as a byte string for display void setup() { for (int i = 0; i < charHeight; i++) pinMode(LEDpins[i], OUTPUT); // set each pin as an output // set the number of wheel rotations // future version should get this value from EEPROM memory // store the value in m then (numWheelRotations = distance * 1000 / wheelCurcum) numWheelRotations = 0; // for now just let it equal 0 // load some text into the byte array updateByteArray("HELP"); } void loop() { // set the LED pattern updateDisplay(); // wait for a while (duration of 1 frame) pauseFrame(1); } void updateDisplay() { if(byteNum < sizeof(byteString)){ byte b = byteString[byteNum]; // check for end of text flag if(b != 0xFF){ // bit shift through the byte and output it to the pins for (int j=0; j<charHeight; j++) { digitalWrite(LEDpins[j], !!(b & (1 << j))); } byteNum++; } } } void pauseFrame(int frames){ unsigned long currentTime; int sensVal; // variable to store the value coming from the sensor unsigned long endTime = (millis() * 1000) + (frames * frameDuration); // calculate the end time while((millis() * 1000) < endTime){ // check the sensor sensVal = analogRead(sensorPIN); // read the Hall Effect Sensor if (sensVal > (mean + sensitivity) || sensVal < (mean - sensitivity)) { currentTime = millis() * 1000; // in microseconds if(currentTime < (startTime + (20 * frameDuration))){ // debounce the sensor reading startTime = currentTime; // reset the start time } else { frameDuration = (currentTime - startTime) / numFrames; // recalculate frameDuration if(frameDuration > 10000) frameDuration = 10000; // limit the frame duration to a reasonable time numWheelRotations++; // add 1 to the number of wheel rotations updateByteArray(newText(currentTime - startTime)); startTime = currentTime; // reset the start time byteNum = 0; break; } } } } char* newText(unsigned long duration){ int n; // number of char written to the string (not used) char newString[70]; // calculate distance unsigned long distancem = numWheelRotations * wheelCurcum / 1000; // distance in metres unsigned long distancekm = distancem / 1000; // distance in km (this truncates the number) unsigned long distanceRem = distancem - (distancekm * 1000); // the bit after the decimal point // calculate speed // mm / microsecond x 1000 is mm / millisecond // mm / millisecond is equivalent to m / sec // m / sec x 60 x 60 is m / hr // m / hr / 1000 is km / hr unsigned long speed100m = wheelCurcum * 36000 / duration; // 100m per hour unsigned long speedkm = speed100m / 10; // km per hour unsigned long speedRem = speed100m - (speedkm * 10); // the bit after the decimal point // print a new text string into the variable n = sprintf (newString, "%ld.%ld km %ld.%ld km/hr \n", distancekm, distanceRem, speedkm, speedRem); return newString; } void updateByteArray(char textString[]) { int x=0; for (int i=0; i<strlen(textString); i++){ char ch = textString[i]; // make sure the character is within the alphabet bounds (defined by the font.h file) // if it's not, make it a blank character if (ch < 32 || ch > 96){ ch = 32; } // subtract the space character ch -= 32; // converts the ASCII number to the font index number // step through each byte of the character array for (int j=0; j<charWidth; j++) { byteString[x++] = font[ch][j]; } // add space between letters for(int k=0; k<letterSpace; k++) { byteString[x++] = 0; } } // add space at the end of the string for(int l=0; l<stringSpace; l++) { byteString[x++] = 0; } // end with an eight bit flag (the text only uses 7 bites) byteString[x] = 0xFF; }
