Examples¶
Here are example use cases for GPIOManager, PWMManager, and I2CManager.
GPIOManager Examples¶
Basic GPIO Input Pin Setup with Callback:
import gpio_manager import time def button_pressed_callback(): print("Button was pressed on pin 17") # Set up GPIO Manager gpio = gpio_manager.GPIOManager() # Configure pin 17 as input with a pull-up resistor gpio.add_input_pin(17, pull_resistor_state=gpio_manager.InternPullResistorState.PULLUP) # Assign callback to the pin for falling edge detection gpio.assign_callback(17, button_pressed_callback, trigger_edge=gpio_manager.TriggerEdge.FALLING) while True: time.sleep(1) pass
GPIO Output Pin Setup and State Change:
import gpio_manager import time # Set up GPIO Manager gpio = gpio_manager.GPIOManager() # Configure pin 18 as an output pin with an initial LOW state gpio.add_output_pin(18, pin_state=gpio_manager.PinState.LOW) # Set pin 18 to HIGH gpio.set_output_pin(18, gpio_manager.PinState.HIGH) time.sleep(2) gpio.cleanup()
Sounding an Alarm on Pin 4 When an object gets to close to an ultrasonic sensor:
import time import gpio_manager start_time = 0 end_time = 0 BUZZER_PIN = 4 TRIGGER_PIN = 23 ECHO_PIN = 24 SPEED_OF_SOUND_MS = 34300 def milliseconds_to_seconds(miliseconds: float) -> float: return miliseconds / 1000 def activate_warning(distance): gpio = gpio_manager.GPIOManager() repeat_count = 3 if 10 < distance < 25: duration_time = milliseconds_to_seconds(250) elif distance < 10: duration_time = milliseconds_to_seconds(150) else: return for _ in range(repeat_count): gpio.set_pwm_duty_cycle(BUZZER_PIN, 90) time.sleep(duration_time) gpio.set_pwm_duty_cycle(BUZZER_PIN, 0) time.sleep(duration_time) def callback(t_time, edge): global start_time global end_time if edge == gpio_manager.TriggerEdge.RISING: start_time = t_time else: end_time = t_time def microseconds_to_seconds(microseconds: float) -> float: return microseconds / 1000000 def setup_gpio() -> gpio_manager.GPIOManager: gpio = gpio_manager.GPIOManager() gpio.add_output_pin(TRIGGER_PIN) gpio.add_input_pin(TRIGGER_PIN) gpio.setup_pwm(BUZZER_PIN, 100) gpio.start_pwm(BUZZER_PIN) return gpio def send_trigger_pulse(): gpio = gpio_manager.GPIOManager() gpio.set_output_pin(TRIGGER_PIN, gpio_manager.PinState.HIGH) time.sleep(microseconds_to_seconds(10)) gpio.set_output_pin(TRIGGER_PIN, gpio_manager.PinState.LOW) def loop(): gpio = gpio_manager.GPIOManager() gpio.assign_callback(ECHO_PIN, callback, gpio_manager.TriggerEdge.BOTH, include_trigger_time=True, include_trigger_edge=True, debounce_time_ms=0) time.sleep(0.5) while True: send_trigger_pulse() time.sleep(0.1) duration = end_time - start_time if duration == 0: print("timeout") time.sleep(3) continue distance = duration * SPEED_OF_SOUND_MS / 2 activate_warning(distance) print(f"Distance: {distance:.2f} cm") time.sleep(0.1) def main(): gpio = setup_gpio() print("Ultrasonic Measurement") print("**************** PROGRAM IS RUNNING **************** ") print("Press CTRL-C to end the program.") try: loop() except KeyboardInterrupt: print("\nCTRL-C detected.") finally: gpio.cleanup() print("GPIO Port has been cleaned up.") print("**************** PROGRAM TERMINATED ****************") print() if __name__ == "__main__": main()
PWMManager Examples¶
PWM Setup and Basic LED Brightness Control:
import gpio_manager # Set up PWM Manager pwm = gpio_manager.PWMManager() # Set up PWM on channel 0, 1000 Hz frequency, and 50% duty cycle pwm.setup_pwm_channel(0, frequency_hz=1000, duty_cycle=50) # Start PWM on channel 0 pwm.start_pwm_channel(0) # Change duty cycle to 75% pwm.set_duty_cycle(0, 75) # Stop PWM on channel 0 pwm.stop_pwm_channel(0)
RGB LED with PWM Control:
import gpio_manager import time # Set up PWM Manager pwm = gpio_manager.PWMManager() # Set up RGB LED pins with PWM (channels 0 and 1) pwm.setup_pwm_channel(0, frequency_hz=1000) pwm.setup_pwm_channel(1, frequency_hz=1000) # Function to cycle RGB colors def cycle_rgb(): for duty_cycle in range(0, 101, 5): pwm.set_duty_cycle(0, duty_cycle) # Red pwm.set_duty_cycle(1, 100 - duty_cycle) # Green time.sleep(0.05) # Start PWM on channels 0 and 1 pwm.start_pwm_channel(0) pwm.start_pwm_channel(1) # Cycle through colors cycle_rgb() # Stop PWM on all channels pwm.cleanup()
Servo motor control on PWM channel 0 (gpio pin 18):
import gpio_manager Period_ms = 20 PWM_CHANNEL = 0 default_pulse_width = 1.5 max_rotation = 90 def setup_gpio(): pwm = gpio_manager.PWMManager() pwm.setup_pwm_channel(PWM_CHANNEL, period_ms=Period_ms, pulse_width_ms=default_pulse_width) pwm.start_pwm_channel(PWM_CHANNEL) def degrees_to_pulse_with(degrees): if degrees < -max_rotation or degrees > max_rotation: raise ValueError("Angle must be between -90 and 90 degrees.") # Mapping -90 degrees to 0.5 ms and 90 degrees to 2.5 ms max_pulse = 2.5 # Pulse width for 90 degrees neutral_pulse = 1.5 # Pulse width for 0 degrees # Slope of the linear equation pulse_width = neutral_pulse + (-degrees / max_rotation) * (max_pulse - neutral_pulse) return pulse_width def get_user_input(): while True: val = input("Please enter an angle in degrees (-90 - 90) or exit to exit: ") if val.lower() == "exit": return None try: int_data = float(val) if -max_rotation <= int_data <= max_rotation: return int_data else: raise ValueError except ValueError: print("invalid value, please try again \n") continue def loop(): pwm = gpio_manager.PWMManager() while True: user_input = get_user_input() if user_input is None: exit() pwm.set_pulse_width(PWM_CHANNEL, degrees_to_pulse_with(user_input)) def main(): try: setup_gpio() loop() except KeyboardInterrupt: print("\nCTRL-C detected.") finally: pwm = gpio_manager.PWMManager() pwm.cleanup() print("GPIO Port has been cleaned up.") print("**************** PROGRAM TERMINATED ****************") print() if __name__ == "__main__": main()
I2CManager Examples¶
Basic I2C Communication:
import gpio_manager # Set up I2C Manager i2c = gpio_manager.I2CManager() # Open I2C bus i2c.open(bus=1) # Write a byte to a slave device at address 0x20 i2c.write_byte(0x20, 0xFF) # Read a byte from the slave device data = i2c.read_byte(0x20) print("Received byte:", data) # Close the I2C bus i2c.close()
I2C Block Read and Write:
import gpio_manager # Set up I2C Manager i2c = gpio_manager.I2CManager() # Open I2C bus i2c.open(bus=1) # Write a block of bytes with a command i2c.block_write(0x20, 0x01, b'\x01\x02\x03') # Read a block of data with a command data = i2c.block_read(0x20, 0x01, 3) print("Received block:", data) # Close the I2C bus i2c.close()