About
This is my entry to Sparkfun’s contest. More info here: https://www.sparkfun.com/news/2115
Software
I made a proof of concept using Python 2.7.10 and then I ported my algorithm to Arduino.
- 3-77hits.TXT: 73 hits
- 4-81hits.TXT: 80 hits
- 5-93hits.TXT: 83 hits
- 6-79hits.TXT: 77 hits
- MysteryDataSet-1.TXT: 177 hits
- MysteryDataSet-2.TXT: 166 hits
My hits are lower than the real. I think that they might be some lost hits because of accelerometer timeout.
Python
This is a simple Python script that I coded to check the number of hits. With this code my results were:
'''
Crowdsourcing Algorithms: BeatBag - A Speed Bag Counter
Gerardo Carmona
https://makeroboticsprojects.wordpress.com/
6/30/2016
License: This code is public domain but you buy me a beer if
you use this and we meet someday (Beerware license).
This is my attempt to get a better hit counter algorithm using
a raw data from an accelerometer. More info
https://www.sparkfun.com/news/2115
'''
# Import libraries
import math
# Variables
c = 0
flag = 0
r = 0
xa=0
ya=0
za=0
x=0
y=0
z=0
e=0
# Files, uncomment file that you want to test. File needs to be
# on the same folder as this script
FILE_NAME = '3-77hits.TXT'
# FILE_NAME = '4-81hits.TXT'
# FILE_NAME = '5-93hits.TXT'
# FILE_NAME = '6-79hits.TXT'
# FILE_NAME = 'MysteryDataSet-1.TXT'
# FILE_NAME = 'MysteryDataSet-2.TXT'
file = open(FILE_NAME, 'r')
for line in file:
#print line
words = line[:-1].split(',')
if not words[0][0] == 'A':
# Save previous values
xa = x
ya = y
za = z
# Get new values
x = (float(words[1]))
y = (float(words[2]))
z = (float(words[3]))
dx = x - xa
dy = y - ya
dz = z - za
r = math.sqrt(dx**2+dy**2+dz**2)
flag = flag + 1
#print r
# Tuning this values could give better results
if r > 900 and flag > 100:
c = c + 1
flag = 0
else:
e = e + 1
print FILE_NAME
print c
print '----'
print "Acc reading errors:", e
Arduino
I don’t have an accelerometer, so I was not able to test my code. Any suggestions/comments/bugs are welcome!
/*
Crowdsourcing Algorithms: BeatBag - A Speed Bag Counter
Gerardo Carmona
https://makeroboticsprojects.wordpress.com/
6/30/2016
License: This code is public domain but you buy me a beer if you use this and we meet someday (Beerware license).
This is a modified version of Nate's code. More info https://www.sparkfun.com/news/2115
I tried to mantein same code with different algorithm to calculate the number of hits.
I didn't tried the code because I don't have an accelerometer. The base code to prove my algorithm is
within this repository
*/
#include <avr/wdt.h> //We need watch dog for this program
#include <Wire.h> // Used for I2C
#include <SparkFun_MMA8452Q.h>
#include <math.h>
#define DISPLAY_ADDRESS 0x71 //I2C address of OpenSegment display
MMA8452Q accel;
int hitCounter = 0; //Keeps track of the number of hits
const int resetButton = 6; //Button that resets the display and counter
const int LED = 13; //Status LED on D3
long lastPrint; //Used for printing updates every second
boolean displayOn; //Used to track if display is turned off or not
//Used in the new algorithm
float lastMagnitude = 0;
float lastFirstPass = 0;
float lastSecondPass = 0;
float lastThirdPass = 0;
long lastHitTime = 0;
int secondsCounter = 0;
//
int prevX;
int dx;
int prevY;
int dy;
int prevZ;
int dz;
float r;
//This was found using a spreadsheet to view raw data and filter it
const float WEIGHT = 0.9;
//This was found using a spreadsheet to view raw data and filter it
const int MIN_MAGNITUDE_THRESHOLD = 900;
//This is the minimum number of ms between possible hits
//We use this to filter out peaks that are too close together
const int MIN_TIME_BETWEEN_HITS = 180;
//This is the number of miliseconds before we turn off the display
long TIME_TO_DISPLAY_OFF = 60L * 1000L * 5L; //5 minutes of no use
int DEFAULT_BRIGHTNESS = 50; //50% brightness to avoid burning out segments after 3 years of use
unsigned long currentTime; //Used for millis checking
void initDisplay();
void setBrightness(int brightness);
void resetDisplay();
void printHits();
void clearDisplay();
void setup()
{
wdt_reset(); //Pet the dog
wdt_disable(); //We don't want the watchdog during init
pinMode(resetButton, INPUT_PULLUP);
pinMode(LED, OUTPUT);
//By default .begin() will set I2C SCL to Standard Speed mode of 100kHz
Wire.setClock(400000); //Optional - set I2C SCL to High Speed Mode of 400kHz
Wire.begin(); //Join the bus as a master
Serial.begin(115200);
Serial.println("Speed Bag Counter");
initDisplay();
clearDisplay();
Wire.beginTransmission(DISPLAY_ADDRESS);
Wire.print("Accl"); //Display an error until accel comes online
Wire.endTransmission();
while(!accel.init()) //Test and intialize the MMA8452
; //Do nothing
clearDisplay();
Wire.beginTransmission(DISPLAY_ADDRESS);
Wire.print("0000");
Wire.endTransmission();
lastPrint = millis();
lastHitTime = millis();
wdt_enable(WDTO_250MS); //Unleash the beast
}
void loop()
{
wdt_reset(); //Pet the dog
currentTime = millis();
if ((unsigned long)(currentTime - lastPrint) >= 1000)
{
if (digitalRead(LED) == LOW)
digitalWrite(LED, HIGH);
else
digitalWrite(LED, LOW);
lastPrint = millis();
}
//See if we should power down the display due to inactivity
if (displayOn == true)
{
currentTime = millis();
if ((unsigned long)(currentTime - lastHitTime) >= TIME_TO_DISPLAY_OFF)
{
Serial.println("Power save");
hitCounter = 0; //Reset the count
clearDisplay(); //Clear to save power
displayOn = false;
}
}
//Still alive?
if (accel.available())
{
//Save previous readings
prevX = accel.x;
prevY = accel.y;
prevZ = accel.z;
//Check the accelerometer
accel.read();
//Caluculate the change between last reading and actual reading
dx = accel.x - prevX;
dy = accel.y - prevY;
dz = accel.z - prevZ;
//Get the magnutude of the changes.
r = (float)sqrt(dx*dx+dy*dy+dz*dz);
currentTime = millis();
if (r > MIN_MAGNITUDE_THRESHOLD)
{
//We have a potential hit!
currentTime = millis();
if ((unsigned long)(currentTime - lastHitTime) >= MIN_TIME_BETWEEN_HITS)
{
hitCounter++;
if (displayOn == false) displayOn = true;
printHits(); //Updates the display
}
}
}
//Check if we need to reset the counter and display
if (digitalRead(resetButton) == LOW)
{
//This breaks the file up so we can see where we hit the reset button
Serial.println();
Serial.println();
Serial.println("Reset!");
Serial.println();
Serial.println();
hitCounter = 0;
resetDisplay(); //Forces cursor to beginning of display
printHits(); //Updates the display
while (digitalRead(resetButton) == LOW) wdt_reset(); //Pet the dog while we wait for you to remove finger
//Do nothing for 250ms after you press the button, a sort of debounce
for (int x = 0 ; x < 25 ; x++)
{
wdt_reset(); //Pet the dog
delay(10);
}
}
}
//This function makes sure the display is at 57600
void initDisplay()
{
resetDisplay(); //Forces cursor to beginning of display
printHits(); //Update display with current hit count
displayOn = true;
setBrightness(DEFAULT_BRIGHTNESS);
}
//Set brightness of display
void setBrightness(int brightness)
{
Wire.beginTransmission(DISPLAY_ADDRESS);
Wire.write(0x7A); // Brightness control command
Wire.write(brightness); // Set brightness level: 0% to 100%
Wire.endTransmission();
}
void resetDisplay()
{
//Send the reset command to the display - this forces the cursor to return to the beginning of the display
Wire.beginTransmission(DISPLAY_ADDRESS);
Wire.write('v');
Wire.endTransmission();
if (displayOn == false)
{
setBrightness(DEFAULT_BRIGHTNESS); //Power up display
displayOn = true;
lastHitTime = millis();
}
}
//Push the current hit counter to the display
void printHits()
{
int tempCounter = hitCounter / 2; //Cut in half
Wire.beginTransmission(DISPLAY_ADDRESS);
Wire.write(0x79); //Move cursor
Wire.write(4); //To right most position
Wire.write(tempCounter / 1000); //Send the left most digit
tempCounter %= 1000; //Now remove the left most digit from the number we want to display
Wire.write(tempCounter / 100);
tempCounter %= 100;
Wire.write(tempCounter / 10);
tempCounter %= 10;
Wire.write(tempCounter); //Send the right most digit
Wire.endTransmission(); //Stop I2C transmission
}
//Clear display to save power (a screen saver of sorts)
void clearDisplay()
{
Wire.beginTransmission(DISPLAY_ADDRESS);
Wire.write(0x79); //Move cursor
Wire.write(4); //To right most position
Wire.write(' ');
Wire.write(' ');
Wire.write(' ');
Wire.write(' ');
Wire.endTransmission(); //Stop I2C transmission
}
Get the code here!
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