Arduino Electric Screwdriver

Modify the servo for screwdriver operation.

1. Open the servo casing carefully.
2. Remove the internal potentiometer.
3. Replace with two fixed resistors (2.2kΩ each).
4. Remove the mechanical stop on the main gear.
5. Reassemble the servo.
6. Test: servo should now rotate continuously in both directions.

Print all required parts.

1. Download STL files from project source.
2. Print with 20-40% infill, PLA filament recommended.
3. Parts needed: main body, grip, bearing mounts, button housing.
4. Clean up support material and test fit parts.

Wire Arduino, joystick, and servo.

1. Connect servo signal wire to Arduino Pin 9.
2. Connect servo VCC to Arduino VIN (6V via barrel jack).
3. Connect servo GND to Arduino GND.
4. Connect joystick VCC to Arduino 5V.
5. Connect joystick GND to Arduino GND.
6. Connect joystick X-axis to Arduino A0.
7. Connect rocker switch to control power on/off.

Program joystick-controlled servo speed.

1. Open Arduino IDE.
2. Copy the screwdriver control sketch below.
3. Upload to Arduino Nano.

#include <Servo.h>

Servo motor;

const int joystickPin = A0;
const int servoPin = 9;

int joystickValue = 0;
int speed = 90;

void setup() {
  motor.attach(servoPin);
  motor.write(90);
}

void loop() {
  joystickValue = analogRead(joystickPin);
  
  // Map joystick to servo speed
  // Center position (512) = stop (90)
  // Left = reverse (0-89)
  // Right = forward (91-180)
  
  if (joystickValue < 400) {
    // Reverse
    speed = map(joystickValue, 0, 400, 0, 89);
  } else if (joystickValue > 600) {
    // Forward
    speed = map(joystickValue, 600, 1023, 91, 180);
  } else {
    // Dead zone - stop
    speed = 90;
  }
  
  motor.write(speed);
  delay(20);
}

Put all parts together.

1. Install 608zz bearings in mounts with hot glue.
2. Mount servo in main housing.
3. Secure Arduino Nano and joystick in grip.
4. Install rocker switch in accessible position.
5. Connect power adapter (6V recommended, 5V works).
6. Use M3 bolts and nuts to secure all components.
7. Test drive and mechanical connection.

Verify tool operation.

1. Power on with rocker switch.
2. Push joystick right to drive clockwise.
3. Push joystick left to drive counterclockwise.
4. Test with actual screws to verify torque.
5. Adjust speed in code if needed.