I needed some way to make a MiniPOV detect when I waved it in the air. So what do you use? An Accelerometer !!
So what I do is that I fix an Accelerometer to the good old 10-segment
display ( it has 10 green LED's put into a single component! ). And
use an Arduino to control it.
So there you have it. As you wave it, it senses this motion and
switches ON the display. And one another benefit that I was really
looking for is that it writes only from left to right. I mean when you
wave your hand it goes left to right to left. Right? My old AccPOV was
amateur enough to keep displaying text all the time left to right and
back too. So that has been eliminated. And its so cool now !
I am calling it the AccPOV that is a accelerometer based Persistence
of Vision Display. Idea of Accelerometer was completely mine, ( deleted: and haven't found it on the net ). Code in C++ attached. You need Arduino
Software to compile it.
Update: I DO NOT mean to say that I am the first one to do this. And yes there are lots of people who have done this thing. Even commercial products have this. I just wanted to say that it struck me that this could be done and so I did it. No copying from here. Though I could have done so very easily due to so many resources on the net !!
The Blue Board is the Arduino Decimelia. It programs and takes power
from the USB ( the grey wire ).
The General Purpose PCB is a 'shield'
which is the word used for attachment boards created for the Arduino.
I have mounted the display on that.
Then the tiny green PCB on the
side is the Accelerometer Board. So that's it. Took one and half day
to materialize.
Next I plan to use RGB LED's to be able to see 6 colors !! So that
should be fun...
Thanks for Reading !! I know it all sounds too formal, as if I am
selling something. But it's just a discussion. A concept...
In case you don't get the heck what I am talking about read this: This
project uses Persistence of Vision. So I can use just 8 LED's (Yes, I
am just using 8 of them. ) to display text. Now as you wave it in the
air, the 8 LEDs quickly change states to appear as if something is
written in the air. It gives superb effect in the dark. For effect in
the daylight I need very bright LEDs... So as simple as that. Just
wave and read.
You can mail me at paramaggarwal@gmail.com for criticism and comments.
Accelerometer:
Three axis accelerometer from Freescale that gives analog voltage
proportional to acceleration. You measure that voltage using a
micro controller and you get acceleration!!
Controller Board:
Arduino's are so easy !! More info about them here: http://www.arduino.cc It
is based on the ATMEGA168 with bootloader.
Have a look at http://www.sparkfun.com for some great Electronics Tutorials.
- Code: Select all
Code:
/*****************
Written by Param Aggarwal
Feemo Electronics
AccPOV
Uses an accelerometer to sense when it is being waved in the air.
Uses Arduino Decimilia and Accelerometer and a custom made shield for the Arduino.
*******************/
/********** Headers ************/
#include<avr/pgmspace.h>
/********* Pins ***********/
// Display goes on PORTD
// GS1 on 10 Sensitivity Selection pins
// GS2 on 11 +- 4g selected here
//SLEEP on 12 and active LOW
int GS1 = 10;
int GS2 = 11;
int SLEEP = 12;
int Y=0; // Temp
int p=0; //Temp
// Tells the microcontroller how to write letters. Little Kid.
// Taken from Sparkfun Library
int text_array[475] = {
0x00,0x00,0x00,0x00,0x00,/*space*/ // is 32 in ASCII
0x00,0xF6,0xF6,0x00,0x00,/*!*/
0x00,0xE0,0x00,0xE0,0x00,/*"*/
0x28,0xFE,0x28,0xFE,0x28,/*#*/
0x00,0x64,0xD6,0x54,0x08,/*$*/
0xC2,0xCC,0x10,0x26,0xC6,/*%*/
0x4C,0xB2,0x92,0x6C,0x0A,/*&*/
0x00,0x00,0xE0,0x00,0x00,/*'*/
0x00,0x38,0x44,0x82,0x00,/*(*/
0x00,0x82,0x44,0x38,0x00,/*)*/
0x88,0x50,0xF8,0x50,0x88,/***/
0x08,0x08,0x3E,0x08,0x08,/*+*/
0x00,0x00,0x05,0x06,0x00,/*,*/
0x08,0x08,0x08,0x08,0x08,/*-*/
0x00,0x00,0x06,0x06,0x00,/*.*/
0x02,0x0C,0x10,0x60,0x80,/*/*/
0x7C,0x8A,0x92,0xA2,0x7C,/*0*/
0x00,0x42,0xFE,0x02,0x00,/*1*/
0x42,0x86,0x8A,0x92,0x62,/*2*/
0x44,0x82,0x92,0x92,0x6C,/*3*/
0x10,0x30,0x50,0xFE,0x10,/*4*/
0xE4,0xA2,0xA2,0xA2,0x9C,/*5*/
0x3C,0x52,0x92,0x92,0x0C,/*6*/
0x80,0x86,0x98,0xE0,0x80,/*7*/
0x6C,0x92,0x92,0x92,0x6C,/*8*/
0x60,0x92,0x92,0x94,0x78,/*9*/
0x00,0x00,0x36,0x36,0x00,/*:*/
0x00,0x00,0x35,0x36,0x00,/*;*/
0x10,0x28,0x44,0x82,0x00,/*<*/
0x28,0x28,0x28,0x28,0x28,/*=*/
0x00,0x82,0x44,0x28,0x10,/*>*/
0x40,0x80,0x8A,0x90,0x60,/*?*/
0x7C,0x82,0xBA,0xBA,0x62,/*@*/
0x3E,0x48,0x88,0x48,0x3E,/*A*/
0xFE,0x92,0x92,0x92,0x6C,/*B*/
0x7C,0x82,0x82,0x82,0x44,/*C*/
0xFE,0x82,0x82,0x82,0x7C,/*D*/
0xFE,0x92,0x92,0x92,0x82,/*E*/
0xFE,0x90,0x90,0x90,0x80,/*F*/
0x7C,0x82,0x82,0x8A,0x4E,/*G*/
0xFE,0x10,0x10,0x10,0xFE,/*H*/
0x82,0x82,0xFE,0x82,0x82,/*I*/
0x84,0x82,0xFC,0x80,0x80,/*J*/
0xFE,0x10,0x28,0x44,0x82,/*K*/
0xFE,0x02,0x02,0x02,0x02,/*L*/
0xFE,0x40,0x20,0x40,0xFE,/*M*/
0xFE,0x60,0x10,0x0C,0xFE,/*N*/
0x7C,0x82,0x82,0x82,0x7C,/*O*/
0xFE,0x90,0x90,0x90,0x60,/*P*/
0x7C,0x82,0x82,0x86,0x7E,/*Q*/
0xFE,0x90,0x98,0x94,0x62,/*R*/
0x64,0x92,0x92,0x92,0x4C,/*S*/
0x80,0x80,0xFE,0x80,0x80,/*T*/
0xFC,0x02,0x02,0x02,0xFC,/*U*/
0xF8,0x04,0x02,0x04,0xF8,/*V*/
0xFC,0x02,0x0C,0x02,0xFC,/*W*/
0xC6,0x28,0x10,0x28,0xC6,/*X*/
0xC0,0x20,0x1E,0x20,0xC0,/*Y*/
0x86,0x8A,0x92,0xA2,0xC2,/*Z*/
0x00,0x00,0xFE,0x82,0x00,/*[*/
0x00,0x00,0x00,0x00,0x00,/*this should be / */
0x80,0x60,0x10,0x0C,0x02,/*]*/
0x20,0x40,0x80,0x40,0x20,/*^*/
0x01,0x01,0x01,0x01,0x01,/*_*/
0x80,0x40,0x20,0x00,0x00,/*`*/
0x04,0x2A,0x2A,0x2A,0x1E,/*a*/
0xFE,0x12,0x22,0x22,0x1C,/*b*/
0x1C,0x22,0x22,0x22,0x14,/*c*/
0x1C,0x22,0x22,0x12,0xFE,/*d*/
0x1C,0x2A,0x2A,0x2A,0x18,/*e*/
0x10,0x7E,0x90,0x80,0x40,/*f*/
0x18,0x25,0x25,0x25,0x1E,/*g*/
0xFE,0x10,0x10,0x10,0x0E,/*h*/
0x00,0x12,0x5E,0x02,0x00,/*i*/
0x02,0x01,0x01,0x11,0x5E,/*j*/
0xFE,0x08,0x08,0x14,0x22,/*k*/
0x00,0x82,0xFE,0x02,0x00,/*l*/
0x3E,0x20,0x1C,0x20,0x1E,/*m*/
0x3E,0x20,0x20,0x20,0x1E,/*n*/
0x1C,0x22,0x22,0x22,0x1C,/*o*/
0x3F,0x24,0x24,0x24,0x18,/*p*/
0x18,0x24,0x24,0x3F,0x01,/*q*/
0x3E,0x10,0x20,0x20,0x10,/*r*/
0x12,0x2A,0x2A,0x2A,0x04,/*s*/
0x00,0x10,0x3C,0x12,0x04,/*t*/
0x3C,0x02,0x02,0x02,0x3E,/*u*/
0x30,0x0C,0x02,0x0C,0x30,/*v*/
0x38,0x06,0x18,0x06,0x38,/*w*/
0x22,0x14,0x08,0x14,0x22,/*x*/
0x38,0x05,0x05,0x05,0x3E,/*y*/
0x22,0x26,0x2A,0x32,0x22,/*z*/
0x00,0x10,0x6C,0x82,0x82,/*{*/
//0x00,0x00,0xFF,0x00,0x00,/*|*/
0x04,0x02,0xFF,0x02,0x04,/*|, arrow*/
0x82,0x82,0x6C,0x10,0x00,/*}*/
0x08,0x10,0x18,0x08,0x10/*~*/
};
// Displays the text
void display(char c)
{
int i = (c - 32)*5;
for ( int temp = i; temp < i + 5; temp++ )
{
PORTD = text_array[temp]; delayMicroseconds(500);
PORTD = 0x00; delay(3);
}
PORTD = 0x00; delay(3);
}
void setup()
{
pinMode(0,OUTPUT); // Set display as OUTPUT
pinMode(1,OUTPUT);
pinMode(2,OUTPUT);
pinMode(3,OUTPUT);
pinMode(4,OUTPUT);
pinMode(5,OUTPUT);
pinMode(6,OUTPUT);
pinMode(7,OUTPUT);
pinMode(8,OUTPUT);
pinMode(9,OUTPUT);
pinMode(10,OUTPUT);
pinMode(11,OUTPUT);
pinMode(12,OUTPUT);
pinMode(13,OUTPUT);
digitalWrite(GS1,HIGH); // Sensitivity Select
digitalWrite(GS2,LOW);
digitalWrite(SLEEP,HIGH); // Don't let the Accelerometer sleep !!!
}
void loop()
{
Y = analogRead(1); // Read the sensor...
if ( Y > 650)
{
p++;
if(p=2) // Take alternate acceleration...
{
p=0;
delay(60); // Wait a moment before starting
display('P'); // Paaaaraaammm...
display('a');
display('r');
display('a');
display('m');
display(':');
display('-');
display(')');
display(' ');
}
}
}
