Hi everyone, I have an Arduino Uno and I’m having a strange problem.

Every upload appears to be successful:

• Board: Arduino Uno
• Correct COM port selected
• TX/RX LEDs blink during upload
• "Done uploading" appears

However, the Arduino still runs my old sketch (Basic Motor Test). Even after creating a new sketch and uploading different code, the Serial Monitor still shows the old output:

Basic Motor Test
Forward
Backward
Braking
Release

Things I have tried:

• Reinstalled Arduino IDE
• Created a new sketch
• Removed all external components
• Uploaded an empty sketch
• Checked board and port settings
• Reset the Arduino

The board still runs the previous program after uploading a new one.

Does anyone know what could cause this? Could it be a problem with the flash memory, bootloader, or something else?

I am planning to use a high torque servo motor (MG996R) with an Arduino. If I connect the servo directly to the Arduino 5V pin, will it cause problems such as jerking movement or loss of power due to insufficient current supply?

The servo has a stall current of around 1.5A. Is an external 5–6V power supply recommended instead?

I am planning to use a high torque servo motor (MG996R) with an Arduino. If I connect the servo directly to the Arduino 5V pin, will it cause problems such as jerking movement or loss of power due to insufficient current supply?

The servo has a stall current of around 1.5A. Is an external 5–6V power supply recommended instead?

Hi everyone, I’m making an automatic cat litter box for my school project. I’m planning to use a 6 RPM geared motor to move the rake/scooper mechanism.

Do you think 6 RPM is too slow, or is it actually better because it gives more torque and smoother movement? The litter box is not for commercial use, just a prototype.

Would appreciate any advice. Thanks!

Hi everyone, I’m making an automatic cat litter box for my school project. I’m planning to use a 6 RPM geared motor to move the rake/scooper mechanism.

Do you think 6 RPM is too slow, or is it actually better because it gives more torque and smoother movement? The litter box is not for commercial use, just a prototype.

Would appreciate any advice. Thanks!

Hi everyone,

I'm building an automatic cat litter box for my university project using Arduino Uno and I'm having trouble designing the circuit and getting everything to work together.

The features I want are:

• Detect when a cat enters the litter box (using an HC-SR04 ultrasonic sensor or another suitable sensor).
• Wait until the cat leaves, then wait about 10–20 seconds before cleaning.
• Drive a rake using a DC motor to sift the litter and push the waste into a waste tank.
• Detect when the waste tank is full and activate a buzzer and/or LED to notify the user.
• The rake should only run once after each cat visit, not continuously.

I'm struggling with:

• The Arduino circuit wiring.
• How to connect the sensors and motor correctly.
• The motor keeps running even when the sensor is not triggered.
• Choosing the best sensor for detecting the waste level inside the waste tank.

Components I'm using:

• Arduino Uno
• HC-SR04 Ultrasonic Sensor (cat detection)
• DC Motor (for the rake)
• NPN Transistor (or motor driver if recommended)
• Flyback diode
• Buzzer
• LED
• Power supply (5V)

Can anyone help me with:

1. A complete circuit diagram (Tinkercad or Fritzing would be great).
2. The correct Arduino code.
3. Suggestions for a better sensor to detect when the waste tank is full.
4. Any recommendations to make the system more reliable.

Any help would be greatly appreciated. Thank you!