R2-D2 Brewbot

Simple Arduino sketches to control a pour spout using an ultrasonic sensor, a servo, and a relay. The default sketch is focused on the spout only and is easy to configure for non-coders.

Sketches

• SpoutOnly.ino: Pour-only control using an ultrasonic sensor. Uses a shouldPour() function for clean, readable logic with edge-triggering and a maximum pour time.
• HeadAndSpout.ino: Combined example (head movement + spout). Optional.
• HeadSpin.ino: Head-only example. Optional.

How it works (SpoutOnly.ino)

1. Reads distance from an ultrasonic sensor (HC-SR04/PING style) and averages a few readings for stability.
2. When a cup moves into range, pouring starts (edge-triggered: far → near).
3. Pouring stops when either:
   • The cup moves away, or
   • The maximum pour time elapses.
4. Pour won’t restart until the cup leaves and returns (re-armed).

Wiring (default pins)

• Ultrasonic TRIGGER → Arduino 2
• Ultrasonic ECHO → Arduino 4
• Servo signal → Arduino 9 (Power from a stable 5V source; do NOT power a large servo from the Arduino 5V pin)
• Relay signal → Arduino 13 (Many relay modules are active-LOW)

Power notes:

• Share ground between Arduino, servo power supply, and relay module.
• If your relay is active-HIGH, invert the HIGH/LOW in pourOn()/pourOff().

Configuration (top of SpoutOnly.ino)

• Pins: TRIGGER_PIN, ECHO_PIN, SERVO_PIN, RELAY_PIN
• Servo angles: POUR_OPEN_ANGLE, POUR_CLOSED_ANGLE
• Trigger distance: POUR_DISTANCE_CM (cup considered “present” when closer than this)
• Max pour time: MAX_POUR_TIME_MS (automatic stop)
• Sampling: SAMPLE_COUNT, SAMPLE_DELAY_MS (stability vs. responsiveness)
• Debug: ENABLE_SERIAL_DEBUG (true/false) and SERIAL_BAUD_RATE (115200)

Build & Upload

1. Open SpoutOnly.ino in the Arduino IDE.
2. Select your board and port.
3. Click Upload.
4. (Optional) If ENABLE_SERIAL_DEBUG is true, open Serial Monitor at 115200 baud to see distance and pour events.

Calibration Tips

• Adjust POUR_OPEN_ANGLE / POUR_CLOSED_ANGLE for your specific spout hardware.
• Tune POUR_DISTANCE_CM so the cup triggers reliably but false triggers are rare.
• Increase SAMPLE_COUNT or SAMPLE_DELAY_MS if readings are noisy.
• If the relay logic seems inverted (on when it should be off), swap the HIGH/LOW in pourOn()/pourOff().

Safety

• Liquids and electronics don’t mix—keep wiring and boards protected from spills.
• Use a proper external 5V supply for the servo and share ground with the Arduino.