API Reference¶
pi_servo_hat¶
Python module for the [SparkFun Pi Servo HAT](https://www.sparkfun.com/products/14328) and [SparkFun Servo pHAT for Raspberry Pi](https://www.sparkfun.com/products/15316). This package should be used in conjunction with the sparkfun_pca9685 package.
- class pi_servo_hat.PiServoHat(address=None, debug=None, min_pt=1, max_pt=2)[source]¶
SparkFun PiServoHat Initialise the qwiic_pca9685 python module at
addresswithi2c_driver.- param address
The I2C address to use for the device. If not provided, the default address is used.
- param i2c_driver
An existing i2c driver object. If not provided a driver object is created.
- return
Constructor Initialization True- Successful False- Issue loading I2C driver
- rtype
Bool
- get_pulse_time()[source]¶
Reads and returns the current min and max pulse times for servo movement
- Returns:
tuple: The minimum and maximum pulse times in milliseconds
- get_pwm_frequency()[source]¶
Reads the PWM frequency used on outputs. 50 Hz is recommended for most servos.
- Returns
PWM Frequency Range: 24 Hz to 1526 Hz
- Return type
Integer
- get_servo_position(channel, swing=None)[source]¶
Reads the specified location for the servo in degrees.
- Parameters
channel – Channel of Servo to Control Range: 0 to 15
swing – Range of Servo Movement 90- 90 Degree Servo 180- 180 Degree Servo
- Returns
Esitmated Position (Degrees)
- Return type
Float
- is_connected()[source]¶
Is an I2C connection established with the device?
- Returns
Device Connection Status True- Connected False- Not Connected
- Return type
Bool
- move_servo_position(channel, position, swing=None)[source]¶
Moves servo to specified location in degrees.
- Parameters
channel – Channel of Servo to Control Range: 0 to 15
position – Position (Degrees) Range: Open, but should between 0 and specified servo ‘swing’. The range is not regulated because most servos have extra room for play (i.e. a 90 degree servo may have a +120 degree usable swing). If ‘None’ is specified, the default setting is 90 degrees.
swing – Range of Servo Movement 90- 90 Degree Servo 180- 180 Degree Servo
- restart()[source]¶
Soft resets the chip and then clears the MODE1 register to restart the PWM functionality. The PWM frequency is returned to the default 50 Hz setting.
- set_duty_cycle(channel, duty_cycle)[source]¶
Moves servo to specified location based on duty-cycle.
- Parameters
channel – Channel of Servo to Control Range: 0 to 15
duty_cycle – Duty-Cycle (Percentage) Float Range: 0 to 100 (%) Resolution: 1/4096
- set_pulse_time(min_pulse_time, max_pulse_time)[source]¶
Updates the minimum and maximum pulse widths for the servos
- Args:
min_pulse_time (float): The new minimum pulse width in ms max_pulse_time (float): The new maximum pulse width in ms
- Returns:
bool: Returns true if update was successful, false if an error was encountered
- set_pwm_frequency(frequency=None)[source]¶
Configures the PWM frequency used on outputs. 50 Hz is the default and recommended for most servos.
- Parameters
frequency – PWM Frequency Range: 24 Hz to 1526 Hz
- Returns
Function Operation True- Successful False- Issue in Execution
- Return type
Bool
NOTE: Changing PWM frequency affects timing for servo positioning. Additionally, the servo position needs to be reset for the output control (on all channels).
The output on all channels is initially turned off after the frequency change, but is re-enabled after any of the channels is reconfigured. However, the new PWM frequency will be in affect, so the timing of the outputs on the other channels will be off. (i.e. if a PWM frequency is doubled; the timing of that signal may be halfed.)