Usage

This section provide sample usage of the raspidevkit package

Blinking an LED

import raspidevkit
import time

machine = raspidevkit.Machine()
led = machine.attach_led(14)
led.turn_on()
time.sleep(3)
led.turn_off()

In this example, first we need to create a Machine object which represents our Raspberry Pi machine and by calling attach_{device} we can spawn a device which we can use to do various things such as for this led, turning on and off.

Specifying Board Layout

By default, the board layout is set to BCM, if you want to set it to BOARD layout you can specify the gpio_mode for the Machine

import raspidevkit
import time

machine = raspidevkit.Machine(gpio_mode=raspidevkit.BOARD)

Logging

The Machine class has also a logger which can be enabled on enable_logging and debug arguments of the Machine class. When debug is True the logger object will be set to debug level regardless of the logger configuration given. Below is a sample configuration for logger, though this is just option

'logging': {
    'format': '%(asctime)s [%(levelname)s] - %(message)s.',
    'file': 'machine.log',
    'level': logging.INFO
}

Motors, Drivers and Etc.

Motors and other devices that may require external drivers that may not be directly connected to the Raspiberry Pi.

Devices such as this requires their respective drivers to be first attach to the Raspiberry Pi then from that driver will spawn the Motor or other device object. Below is a sample snippet for L298N motor driver.

import raspidevkit
import time

machine = raspidevkit.Machine()
pins = (12, 13, 14)
l298n = machine.attach_l298n(pins)
motor = l298n.attach_motor()
motor.run()
time.sleep(5)
motor.stop()

You can also set the speed of the motor by enabling the PWM mode of the motor by setting is_pwm to True when attaching motor to the drive

motor = l298n.attach_motor(is_pwm=True)

I2C Communication

The library will also support devices that uses I2C Protocol for communications. By default, when initializing the Machine object, the I2C interface is not enabled yet. You can enable it by setting the i2cbus to the bus you want to use. For Raspi4 and above it is 1.

import raspidevkit
import time

machine = raspidevkit.Machine(i2cbus=1)

As of this writing, the I2C communication is still in testing mode and currently no devices has been implemented yet :(

Arduino Boards

Raspidevkit also supports controlling devices that are attached to an Arduino in which the Arduino is attached to the Raspberry Pi. As of now, the currenly supported communication mode is just for serial. This also features auto code generation, compilation and upload to the Arduino Board.

Auto Code Generation and Upload

If you plan to use the auto upload feature, you must first install the arduino-cli in your system. Below is a sample snippet with auto upload feature.

import raspidevkit
import time

machine = raspidevkit.Machine(arduino_cli_path=r'/path/to/arduino-cli')
arduino = machine.attach_arduino('/tty/USB0', timeout=5)
led = arduino.attach_led(13)
arduino.compile()
led.turn_on()
time.sleep(3)
led.turn_off()

The principle of drivers mentioned above is also true for the arduino board wherein we attached first the arduino object on the machine then spawning the LED object from the arduino. The Arduino object is also just a subclass of serial.Serial object so any other arguments such as baudrate can also be applied when initializing the object. I also recommend putting a timeout of higher than 3 especially when dealing with devices that needs to send higher size of data to the Arduino.

When working with the Arduino, it is required to call the compile method which would handle the code generation and auto upload of the code to the Arduino board. So, before you call this method make sure that all devices you want to use in your Arduino Board are declared as this will only include devices attached up until the compile method was called.

Without Arduino-cli

If you have not installed the arduino-cli in your system or the library could not find the arduino-cli in the path you have provided. Then it will throw an exception when the compile method was called. You can however generate the code and have it manually uploaded to the Arduino. Here’s how:

import raspidevkit
import time

machine = raspidevkit.Machine()
arduino = machine.attach_arduino('/tty/USB0', timeout=5)
led = arduino.attach_led(13)
arduino.generate_code('test.ino')
### Have it uploaded then run the script again ###
led.turn_on()
time.sleep(3)
led.turn_off()

Here, we first generate the code to the file test.ino and manually uploaded the sketch file to the Arduino. after the sketch is uploaded we can then skip the code generation part and control our LED. However, this may be too much time-consuming in the long run