想想當(dāng)你好不容易跟女朋友共度燭光晚餐，卻因?yàn)橄灎T點(diǎn)沒(méi)了或打翻著火了，那是一件多么坑爹的事啊!今天為你分享一款自己diy的超自然的燭光蠟燭。

 

ATtiny 電子蠟燭，皮特•米爾斯開(kāi)發(fā)這個(gè)偉大的蠟燭，正如我們圖片所見(jiàn)到的一樣，但怎樣讓這蠟燭的光芒像傳統(tǒng)的蠟燭一樣閃爍呢。

 

皮特使用一個(gè)高亮的LED和一些模擬的輔助軟件，這樣就使得ATtiny 電子蠟燭的燭光和傳統(tǒng)蠟燭擁有一樣的閃爍的燭光，并且優(yōu)于傳統(tǒng)蠟燭，因?yàn)樗话橛忻骰鸬奈ｋU(xiǎn)。

 

ATtiny 電子蠟燭最難的部分就閃爍神態(tài)逼真，所以皮特做了一個(gè)蠟燭光檢測(cè)電阻( LDR )和固定電阻作為一個(gè)分壓器。這是作為ATTINY85 ADC之中的一個(gè)輸入端，并離散時(shí)間間隔的進(jìn)行采樣。采樣速率為100毫秒。然后將采集的8bit的電頻值存儲(chǔ)到EEPROM中，以便記錄蠟燭的閃爍圖譜，驅(qū)動(dòng)將其連接的LED、PWM形成通路。在用三節(jié)干電池供電。最后您只需編程程序，然后通過(guò)開(kāi)關(guān)進(jìn)行控制。

 

下面是ATtiny 電子蠟燭的電路圖

 

下面是程序的代碼以及寫入EEPROM的數(shù)據(jù)

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/*

Program Description: This program reads a light detecting resistor thru an internal ADC and stores the value,

after scaling it, to eeprom. This ADC value is sent to a PWM channel with attached led. This is essentially a data logger

for light and replay by LED. If, if you aim the LDR at a flickering candle during its recording phase, you have a flickering

led candle.

A circuit description and other details can be found at http://petemills.blogspot.com

Filename: ATTiny_Candle_v1.0.c

Author: Pete Mills

Int. RC Osc. 8 MHz; Start-up time PWRDWN/RESET: 6 CK/14 CK + 64 ms

*/

//********** Includes **********

#include

#include

#include

//********** Definitions **********

// LED for flame simulation

#define LED PB0

#define LED_PORT PORTB

#define LED_DDR DDRB

// Light Detecting Resistor for recording a live flame

#define LDR PINB3

#define LDR_PORT PINB

#define LDR_DDR DDRB

// Tactile Switch Input

#define SW1 PINB4

#define SW1_PORT PINB

#define SW1_DDR DDRB

#define ARRAY_SIZE 500 // size of the flicker array

#define SAMPLE_RATE 100 // ms delay for collecting and reproducing the flicker

//********** Function Prototypes **********

void setup(void);

void toggle_led(void);

void program_flicker(void);

void led_alert(void);

void eeprom_save_array(void);

void eeprom_read_array(void);

void scale_array(void);

uint8_t get_adc(void);

uint8_t scale( uint8_t input, uint8_t inp_low, uint8_t inp_hi, uint8_t outp_low, uint8_t outp_hi);

uint8_t is_input_low(char port, char channel, uint8_t debounce_time, int input_block);

//********** Global Variables **********

uint8_t flicker_array[ ARRAY_SIZE ] = { 0 };

uint8_t EEMEM ee_flicker_array[ ARRAY_SIZE ] = { 0 };

int main(void)

{

uint16_t replay = 0;

setup();

eeprom_read_array();

while(1)

{

if( is_input_low( SW1_PORT, SW1, 25, 250 ) )

{

// program the flicker

// after entering and upon completion, a predetermined flash pattern will occur as described in led_alert()

// aim the ldr at a flickering candle or any other light source ( like a laser ) you want to record during this time

// and upon completion the values are stored to eeprom. They are played back immediately as well

// as being recalled from eeprom upon first start up

led_alert();

program_flicker();

scale_array();

eeprom_save_array();

led_alert();

}

// replay the recorded flicker pattern

OCR0A = flicker_array[ replay ];

++replay;

if( replay >= ( ARRAY_SIZE - 13 ) ) // if the end of the stored array has been reached

{

replay = 0; // start again from the beginning

//led_alert();

}

_delay_ms( SAMPLE_RATE );

_delay_ms( 3 ); // ADC Conversion time

}

}

//********** Functions **********

void setup(void)

{

//********* Port Config *********

LED_DDR |= ( 1 << LED); // set PB0 to "1" for output

LED_PORT &= ~( 1 << LED ); // turn the led off

LDR_DDR &= ~( 1 << LDR ); // set LDR pin to 0 for input

LDR_PORT |= ( 1 << LDR ); // write 1 to enable internal pullup

SW1_DDR &= ~( 1 << SW1 ); // set sw1 pin to 0 for input

SW1_PORT |= ( 1 << SW1 ); // write a 1 to sw1 to enable the internal pullup

//********** PWM Config *********

TCCR0A |= ( ( 1 << COM0A1 ) | ( 1 << WGM01 ) | ( 1 << WGM00 ) ); // non inverting fast pwm

TCCR0B |= ( 1 << CS00 ); // start the timer

//********** ADC Config **********

ADMUX |= ( ( 1 << ADLAR ) | ( 1 << MUX1 ) | ( 1 << MUX0 ) ); // left adjust and select ADC3

ADCSRA |= ( ( 1 << ADEN ) | ( 1 << ADPS2 ) | ( 1 << ADPS1 ) ); // ADC enable and clock divide 8MHz by 64 for 125khz sample rate

DIDR0 |= ( 1 << ADC3D ); // disable digital input on analog input channel to conserve power

}

void toggle_led()

{

LED_PORT ^= ( 1 << LED );

}

uint8_t is_input_low( char port, char channel, uint8_t debounce_time, int input_block )

{

/*

This function is for debouncing a switch input

Debounce time is a blocking interval to wait until the input is tested again.

If the input tests low again, a delay equal to input_block is executed and the function returns ( 1 )

*/

if ( bit_is_clear( port, channel ) )

{

_delay_ms( debounce_time );

if ( bit_is_clear( port, channel ) )

{

_delay_ms( input_block );

return 1;

}

}

return 0;

}

uint8_t get_adc()

{

ADCSRA |= ( 1 << ADSC ); // start the ADC Conversion

while( ADCSRA & ( 1 << ADSC )); // wait for the conversion to be complete

return ~ADCH; // return the inverted 8-bit left adjusted adc val

}

void program_flicker()

{

// build the flicker array

for( int i = 0; i < ARRAY_SIZE; i++ )

{

flicker_array[ i ] = get_adc();

_delay_ms( SAMPLE_RATE );

}

}

void led_alert()

{

// this is a function to create a visual alert that an event has occured within the program

// it toggles the led 10 times.

for( int i = 0; i < 10; i++ )

{

OCR0A = 0;

_delay_ms( 40 );

OCR0A = 255;

_delay_ms( 40 );

}

}

void eeprom_save_array()

{

for( int i = 0; i < ARRAY_SIZE; i++ )

{

eeprom_write_byte( &ee_flicker_array[ i ], flicker_array[ i ] );

}

}

void eeprom_read_array()

{

for( int i = 0; i < ARRAY_SIZE; i++ )

{

flicker_array[ i ] = eeprom_read_byte( &ee_flicker_array[ i ] );

}

}

uint8_t scale( uint8_t input, uint8_t inp_low, uint8_t inp_hi, uint8_t outp_low, uint8_t outp_hi)

{

return ( ( ( input - inp_low ) * ( outp_hi - outp_low ) ) / ( ( inp_hi - inp_low ) + outp_low ) );

}

void scale_array()

{

uint8_t arr_min = 255;

uint8_t arr_max = 0;

uint8_t out_low = 20;

uint8_t out_high = 255;

// find the min and max values

for( int i = 0; i < ARRAY_SIZE; i++ )

{

if( flicker_array[ i ] < arr_min )

arr_min = flicker_array[ i ];

if( flicker_array[ i ] > arr_max )

arr_max = flicker_array[ i ];

}

// now that we know the range, scale it

for( int i = 0; i < ARRAY_SIZE; i++ )

{

flicker_array[ i ] = scale( flicker_array[ i ], arr_min, arr_max, out_low, out_high );

}

} igh );

}

} igh );

}

}

}

}

}

}

}

} }

} }

} }

}

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