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mohitbhoite/tinycubesat.cpp

Last active September 30, 2025 00:04
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Revisions

  1. mohitbhoite revised this gist Jun 13, 2021. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion tinycubesat.cpp
    View file
    Original file line number Diff line number Diff line change
    @@ -16,7 +16,7 @@ ISR(WDT_vect) {

    void loop() {
    setup_watchdog(8); //Setup watchdog to go off after 1sec
    sleep_mode(); //Go to sleep! Wake up 2 sec later and check water
    sleep_mode(); //Go to sleep! Wake up 4 sec later
    for(int j=0;j<5;j++)
    {
    digitalWrite(0, HIGH);
  2. mohitbhoite created this gist Jun 13, 2021.
    45 changes: 45 additions & 0 deletions tinycubesat.cpp
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,45 @@
    #include <avr/sleep.h> //Needed for sleep_mode
    #include <avr/wdt.h> //Needed to enable/disable watch dog timer

    void setup() {
    pinMode(0, OUTPUT);// LED connected to pin 5 which is recognised as pin 0 by arduino
    ADCSRA &= ~(1<<ADEN); //Disable ADC, saves ~230uA
    //Power down various bits of hardware to lower power usage
    set_sleep_mode(SLEEP_MODE_PWR_DOWN); //Power down everything, wake up from WDT
    sleep_enable();
    }

    //This runs each time the watch dog wakes us up from sleep
    ISR(WDT_vect) {
    //watchdog_counter++;
    }

    void loop() {
    setup_watchdog(8); //Setup watchdog to go off after 1sec
    sleep_mode(); //Go to sleep! Wake up 2 sec later and check water
    for(int j=0;j<5;j++)
    {
    digitalWrite(0, HIGH);
    delay(20);
    digitalWrite(0, LOW);
    delay(30);
    }
    }

    //Sets the watchdog timer to wake us up, but not reset
    //0=16ms, 1=32ms, 2=64ms, 3=128ms, 4=250ms, 5=500ms
    //6=1sec, 7=2sec, 8=4sec, 9=8sec
    //From: http://interface.khm.de/index.php/lab/experiments/sleep_watchdog_battery/
    void setup_watchdog(int timerPrescaler) {

    if (timerPrescaler > 9 ) timerPrescaler = 9; //Limit incoming amount to legal settings

    byte bb = timerPrescaler & 7;
    if (timerPrescaler > 7) bb |= (1<<5); //Set the special 5th bit if necessary

    //This order of commands is important and cannot be combined
    MCUSR &= ~(1<<WDRF); //Clear the watch dog reset
    WDTCR |= (1<<WDCE) | (1<<WDE); //Set WD_change enable, set WD enable
    WDTCR = bb; //Set new watchdog timeout value
    WDTCR |= _BV(WDIE); //Set the interrupt enable, this will keep unit from resetting after each int
    }