Hello all, first post on these forums. Not highly experienced in electronics, but a learner. Physics major.
I am attempting to build an automated cat feeder based on similar designs found on the internet. The device uses a gravity feed with a servo to align holes for food dispensing. An RTC breakout is used for time keeping and alarm activation. The device is powered by 4x AA batteries, and uses a boost converter breakout module to provide the higher voltage needed by the servo.
An N-channel MOSFET is being used as a control switch for the boost converter. When enabled by the Arduino, it turns on the boost converter. This will help save battery life.
THE PROBLEM: As currently set up, the servo fails to operate correctly, only giving some small jerking motions. I have confirmed the servo works properly in other configurations. The circuit is prototyped as shown in the Fritzing sketch below. I'm also attaching the fritzing file.
I suspect I might have a ground path problem? Can anyone help with that?
Parts:
- Arduino Micro
- DS3231 break-out RTC
- "Mod360" 2-24v boost conveter
- IRJ520 mosfet
- MG996R servo
- Small parts as indicated
Current code:
// Cat Feeder Servo WIP
#include "RTClib.h"
#include "Wire.h"
#include <Servo.h>
#define sec 1000
#define FIRST_COMPILE 0
#define servoPin 4
#define servoPowerPin 12
Servo myservo;
RTC_DS3231 rtc;
char daysOfTheWeek[7][12] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
DateTime alarm1;
void setup () {
Serial.begin(57600);
while (!Serial);
Serial.println("<Arduino is ready>");
// MOSFET on
pinMode(servoPowerPin, OUTPUT);
digitalWrite(servoPowerPin, HIGH);
myservo.attach(servoPin);
rtc.begin();
// Only needed when setting the RTC to compile time aka system time
if (FIRST_COMPILE) { setRTC(); }
// Clear any existing alarms in the RTC
rtc.clearAlarm(1);
rtc.clearAlarm(2);
// Set servo start position
adjustServo(0);
if (rtc.lostPower()) {
Serial.println("RTC lost power, setting to compile time");
setRTC();
}
// Alarm once every minute
alarm1 = rtc.now() + TimeSpan(60);
Ds3231Alarm1Mode alarm_mode = DS3231_A1_Second;
if (rtc.setAlarm1(alarm1, alarm_mode)) {
Serial.print("alarm1 was set to: ");
Serial.print(alarm1.year(), DEC);
Serial.print('/');
Serial.print(alarm1.month(), DEC);
Serial.print('/');
Serial.print(alarm1.day(), DEC);
Serial.print(" (");
Serial.print(daysOfTheWeek[alarm1.dayOfTheWeek()]);
Serial.print(") ");
Serial.print(alarm1.hour(), DEC);
Serial.print(':');
Serial.print(alarm1.minute(), DEC);
Serial.print(':');
Serial.print(alarm1.second(), DEC);
Serial.println();
Serial.println();
} else {
Serial.print("alarm1 was not sucessfully set!");
Serial.println();
}
// End Setup
}
void loop () {
// Print time every X seconds
// Check to see if the alarm was triggered
// Move servo
// Print current RTC clock time
DateTime now = rtc.now();
Serial.print("Current time: ");
Serial.print(now.year(), DEC);
Serial.print('/');
Serial.print(now.month(), DEC);
Serial.print('/');
Serial.print(now.day(), DEC);
Serial.print(" (");
Serial.print(daysOfTheWeek[now.dayOfTheWeek()]);
Serial.print(") ");
Serial.print(now.hour(), DEC);
Serial.print(':');
Serial.print(now.minute(), DEC);
Serial.print(':');
Serial.print(now.second(), DEC);
Serial.println();
// Check for alarm
if (rtc.alarmFired(1)) {
Serial.println("!!!!!!!!!!!!!!!!!!Alarm 1 fired!!!!!!!!!!!!!!!!!!!!!!!!!!!");
Serial.println();
// Adjust servo to 90 deg then back to 0 deg
adjustServo(90);
adjustServo(0);
// Clear alarm flag
rtc.clearAlarm(1);
}
// Wait 10 seconds
delay(10*sec);
}
// Sets the RTC to compile time of the sketch
// This is only needed if the RTC is off time or when first setting the time
void setRTC() {
rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
}
// Set servo angle with 0.5 second delay
void adjustServo(int angle) {
myservo.write(angle);
delay(500);
}
Cat_Feeder.zip (78.9 KB)
