ATtiny85: prototipe sensor nirkabel

Biasanya, untuk beralih dari ide ke implementasi, prototipe perangkat diperlukan, nyaman untuk memeriksa dan debugging di tempat, yang sangat penting untuk perangkat seluler. Selanjutnya, saya akan mencoba menganalisis secara terperinci proses pembuatan prototipe sensor nirkabel berbasis ATtiny85.

— , , : , , . CR2032, , 2.7V ( TMP36), 200mAh.

ATtiny85 5 / RESET . :

• 3 — NRF24L01+, , 3- ;
• 1 — BPW17N;
• 2 — TMP36, , .

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RESET /

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Arduino ATTiny Fuse Reset with 12 Volt Charge Pump. , 12V (Charge Pump).

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KiCad GitHub, attwlight_sensor.pcb.

, YouTube KiCAD Quick-Start Tutorial.

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TMP36

PB5 . VCC D10 P2. RESET RESET. ADC2.

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NRF24L01+

KiCad , NRF24L01+. 3 MISO MOSI, , : R3, D1 C2. nRF24L01+ with ATtiny85 3 Pins.

, CE (chip enable) , CSN (chip select) , . , CSN , SCK (clock). SCK C2 CSN , SCK , CSN. MISO MOSI , .

1-10μF , C4.

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ATtiny85

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BPW17N

, , . PCINT3 (Pin Change Interrupt).

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IDE

Arduino IDE AVR .

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. Tools → Board , : ATtiny85 @ 1 MHz (internal oscillator; BOD disabled), Tools → Port USB Tools → Programmer , : Arduino as ISP, Upload.

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• NRF24L01+;
• ;
• ;
• WDT (WatchDog Timer);
• Pin Change PCINT;
• .

:

• TMRh20/RF24
• TMRh20/RF24Network

NRF24L01+, ATtiny85. libraries Arduino.

. GitHub attwlight_sensor, attwlight_rx .

void sleep() void loop() PCINIT3 WDT. .

, . ATtiny85 datasheet «23. Register Summary», .

#include <avr/wdt.h>
#include <avr/sleep.h>
#include <avr/interrupt.h>

#define WDTO_INFINITE 255
#define SLEEP_PERIOD WDTO_8S
#define SKIP_WDT_WAKEUPS 14 // x SLEEP_PERIOD + SLEEP_PERIOD (14 ~= 120 sec)

//  ()  PCINT,  ATtiny85   (B),     PCINT
ISR(PCINT0_vect)
{
  light_pcint = true;
}

//    WDT
ISR(WDT_vect)
{
  wakeup_counter++;
}

void sleep()
{
  GIMSK = _BV(PCIE); //  Pin Change 
  if (SLEEP_PERIOD == WDTO_INFINITE || payload.light != LIGHT_FUZZY)
    PCMSK |= _BV(LIGHT_PIN); // PCINT3;           
  ADCSRA &= ~_BV(ADEN); //  ADC;  

  if (SLEEP_PERIOD != WDTO_INFINITE) {
    wdt_enable(SLEEP_PERIOD); //  
    WDTCR |= _BV(WDIE); //    ;   ATtiny85
  }

  //    Power-down; MCUSR &= ~_BV(SM0); MCUSR |= _BV(SM1);
  set_sleep_mode(SLEEP_MODE_PWR_DOWN);
  sleep_enable(); //   ; MCUSR |= _BV(SE);
  sei(); //  

  sleep_cpu(); // 

  cli(); //  ;    PCINT3
  PCMSK &= ~_BV(LIGHT_PIN); // PCINT3; 
  sleep_disable(); //   ; MCUSR &= ~_BV(SE);
  ADCSRA |= _BV(ADEN); //  ADC
  sei(); //  ;     
}

« ». , , 20μA.

#define FUZZY_VOLTAGE 0.4 //      ,  

const unsigned int fuzzy_start = int(1024.0 * (1.0 - FUZZY_VOLTAGE) / 2.0);
const unsigned int fuzzy_stop = 1023 - fuzzy_start;

light_t readLightStatus(unsigned int ms)
{
  delay(ms); //     
  int input = analogRead(LIGHT_PIN); // ADC3

  //   
  if (input >= fuzzy_start && input <= fuzzy_stop)
    return LIGHT_FUZZY;
  if (input < fuzzy_start)
    return LIGHT_OFF;
  if (input > fuzzy_stop)
    return LIGHT_ON;

  // ;     
  return LIGHT_UNKNOWN;
}

AREF , , . , , . .

, Vbg (Bandgap reference voltage) 1.1V. Vbg 1.0-1.2V, 1125300.

long readVcc()
{
  //    Vcc    Vbg == 1.1V
  ADMUX = _BV(MUX3) | _BV(MUX2);
  delay(2); //   1ms  
  ADCSRA |= _BV(ADSC); // ADC Start conversion -  
  while (bit_is_set(ADCSRA, ADSC)); // ADSC == 1   

  //  ADCL  ADCH,  ADCH    => ADCL  
  uint8_t low  = ADCL; //    ADC
  uint8_t high = ADCH; //    ADC

  long result = (high << 8) | low;

  result = 1125300L / result; // 1125300 = 1.1*1023*1000
  return result; // Vcc  
}

, .

float readTmp36(long vcc)
{
  int input = analogRead(TMP36_PIN); //   refVolts
  float refVolts = float(vcc) / 1000.0;
  float voltage = float(input) * refVolts / 1024.0; //  
  float temperatureC = (voltage - 0.5) * 100.0; //  500mV & 10mV == 1°C
  return temperatureC;
}

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, , 8KiB :

Sketch uses 7,120 bytes (86%) of program storage space. Maximum is 8,192 bytes.
Global variables use 227 bytes (44%) of dynamic memory, leaving 285 bytes for local variables. Maximum is 512 bytes.

, , Fuses RESET /. Arduino IDE , :

avrdude -c stk500v1 -p attiny85 -P /dev/ttyUSB0 -v -C /etc/avrdude.conf -b 19200 -U lfuse:w:0x62:m -U hfuse:w:0x5f:m -U efuse:w:0xff:m

• avrdude — Arduino IDE hardware/tools/avr/bin/;
• /dev/ttyUSB0 — ;
• /etc/avrdude.conf — Arduino IDE hardware/tools/avr/etc/avrdude.conf.

Fuses, Engbedded Atmel AVR® Fuse Calculator.

, : 8 ( 1MHz); , ; BOD (Brown-out Detector) — ; ; RESET.

. : 120sec, , ; ; 200mAh.

, . , 8MHz . , .

GitHub