SERVO module

About this

This module contains functions to control RC servo motors.

Key concepts

A servo is a rotary actuator, and typically consists of a small electric motor, driving a train of reduction gears, controlled by a control circuit. Historically servos have ben used for radio control and small-scale robotics.

Radio control servos are connected through a standard three-wire connection:

• power: typically the red wire, that must be connected to a +5V power supply.
• ground: typically the black or brown wire, that must be connected to the board's and power's supply ground.
• signal: typically the yellow, orange or white wire, that must be connected to a board's GPIO.

Never connect the power wire to a GPIO, or your board will be permanently damage.

To use a servo in your program you must do the following:

1. Attach the servo using the servo.attach(..) function. This returns a servo instance that you must store into a variable.

   -- Attach the servo to GPIO26
   s = servo.attach(pio.GPIO26)
   

2. Write values to the servo to move it, using the instance's write function.

   -- Move the servo to the 45º position
   s:write(25)
   

Configuration funcions

instance = servo.attach(pin)

Create a new servo instance.

Arguments:

• pin: GPIO to use for the servo signal. Use defined constants in the PIO module for this, for example pio.GPIO126.

Returns: a servo instance, or an exception. You must store this instance into a variable for further operations with it.

Operation functions

instance:write(angle)

Write an angle value to a servo instance, moving the servo by the specified angle.

Arguments:

• angle: the angle, expressed in degrees to move the servo.

Returns: nothing, or an exception.