This post is going to be somewhat rambling without a clear destination, as this is my initial foray into configuring the Rpi to interact with sensors and such, and thus will be filled with my pokings and proddings. Here we go!

First, I have been using the book ‘Make: Linux for Makers’ by Aaron Newcomb, which has been helpful for tying in the linux aspects with Rpi. Aaron mentions that thereare several programming modules or libraries that you can use to control the GPIO pins on a Rpi, including RPi.GPIO, but he suggested pigpio so that’s the one I went with, too. To download that module, I used the following command in my terminal shell window on Rpi:

wget https://github.com/joan2937/pigpio/archive/master.zip
unzip master.zip
cd pigpio-master
make
sudo make install

I used a headless setup to work with these steps, and there was no problem downloading or installing these files. Here’s the link to the Python interface for the module. Pigpio runs as a daemon process in the background, and then Python class instances are created in order to control individual RPi’s pins. Here’s an example of doing that

pi1 = pigpio.pi()       # pi1 accesses the local Pi's GPIO
pi2 = pigpio.pi('tom')  # pi2 accesses tom's GPIO
pi3 = pigpio.pi('dick') # pi3 accesses dick's GPIO

pi1.write(4, 0) # set local Pi's GPIO 4 low
pi2.write(4, 1) # set tom's GPIO 4 to high
pi3.read(4)     # get level of dick's GPIO 4

OVERVIEW

ESSENTIAL
pigpio.pi	Initialise Pi connection
stop	Stop a Pi connection
BASIC
set_mode	Set a GPIO mode
get_mode	Get a GPIO mode
set_pull_up_down	Set/clear GPIO pull up/down resistor
read	Read a GPIO
write	Write a GPIO
PWM (overrides servo commands on same GPIO)
set_PWM_dutycycle	Start/stop PWM pulses on a GPIO
set_PWM_frequency	Set PWM frequency of a GPIO
set_PWM_range	Configure PWM range of a GPIO
get_PWM_dutycycle	Get PWM dutycycle set on a GPIO
get_PWM_frequency	Get PWM frequency of a GPIO
get_PWM_range	Get configured PWM range of a GPIO
get_PWM_real_range	Get underlying PWM range for a GPIO
Servo (overrides PWM commands on same GPIO)
set_servo_pulsewidth	Start/Stop servo pulses on a GPIO
get_servo_pulsewidth	Get servo pulsewidth set on a GPIO
INTERMEDIATE
gpio_trigger	Send a trigger pulse to a GPIO
set_watchdog	Set a watchdog on a GPIO
read_bank_1	Read all bank 1 GPIO
read_bank_2	Read all bank 2 GPIO
clear_bank_1	Clear selected GPIO in bank 1
clear_bank_2	Clear selected GPIO in bank 2
set_bank_1	Set selected GPIO in bank 1
set_bank_2	Set selected GPIO in bank 2
callback	Create GPIO level change callback
wait_for_edge	Wait for GPIO level change
ADVANCED
notify_open	Request a notification handle
notify_begin	Start notifications for selected GPIO
notify_pause	Pause notifications
notify_close	Close a notification
hardware_clock	Start hardware clock on supported GPIO
hardware_PWM	Start hardware PWM on supported GPIO
set_glitch_filter	Set a glitch filter on a GPIO
set_noise_filter	Set a noise filter on a GPIO
set_pad_strength	Sets a pads drive strength
get_pad_strength	Gets a pads drive strength
shell	Executes a shell command
Custom
custom_1	User custom function 1
custom_2	User custom function 2
Events
event_callback	Sets a callback for an event
event_trigger	Triggers an event
wait_for_event	Wait for an event
Scripts
store_script	Store a script
run_script	Run a stored script
update_script	Set a scripts parameters
script_status	Get script status and parameters
stop_script	Stop a running script
delete_script	Delete a stored script
I2C
i2c_open	Opens an I2C device
i2c_close	Closes an I2C device
i2c_write_quick	SMBus write quick
i2c_read_byte	SMBus read byte
i2c_write_byte	SMBus write byte
i2c_read_byte_data	SMBus read byte data
i2c_write_byte_data	SMBus write byte data
i2c_read_word_data	SMBus read word data
i2c_write_word_data	SMBus write word data
i2c_read_block_data	SMBus read block data
i2c_write_block_data	SMBus write block data
i2c_read_i2c_block_data	SMBus read I2C block data
i2c_write_i2c_block_data	SMBus write I2C block data
i2c_read_device	Reads the raw I2C device
i2c_write_device	Writes the raw I2C device
i2c_process_call	SMBus process call
i2c_block_process_call	SMBus block process call
i2c_zip	Performs multiple I2C transactions
I2C BIT BANG
bb_i2c_open	Opens GPIO for bit banging I2C
bb_i2c_close	Closes GPIO for bit banging I2C
bb_i2c_zip	Performs multiple bit banged I2C transactions
I2C/SPI SLAVE
bsc_xfer	I2C/SPI as slave transfer
bsc_i2c	I2C as slave transfer
SERIAL
serial_open	Opens a serial device
serial_close	Closes a serial device
serial_read_byte	Reads a byte from a serial device
serial_write_byte	Writes a byte to a serial device
serial_read	Reads bytes from a serial device
serial_write	Writes bytes to a serial device
serial_data_available	Returns number of bytes ready to be read
SERIAL BIT BANG (read only)
bb_serial_read_open	Open a GPIO for bit bang serial reads
bb_serial_read_close	Close a GPIO for bit bang serial reads
bb_serial_invert	Invert serial logic (1 invert, 0 normal)
bb_serial_read	Read bit bang serial data from a GPIO
SPI
spi_open	Opens a SPI device
spi_close	Closes a SPI device
spi_read	Reads bytes from a SPI device
spi_write	Writes bytes to a SPI device
spi_xfer	Transfers bytes with a SPI device
SPI BIT BANG
bb_spi_open	Opens GPIO for bit banging SPI
bb_spi_close	Closes GPIO for bit banging SPI
bb_spi_xfer	Transfers bytes with bit banging SPI
FILES
file_open	Opens a file
file_close	Closes a file
file_read	Reads bytes from a file
file_write	Writes bytes to a file
file_seek	Seeks to a position within a file
file_list	List files which match a pattern
WAVES
wave_clear	Deletes all waveforms
wave_add_new	Starts a new waveform
wave_add_generic	Adds a series of pulses to the waveform
wave_add_serial	Adds serial data to the waveform
wave_create	Creates a waveform from added data
wave_create_and_pad	Creates a waveform of fixed size from added data
wave_delete	Deletes a waveform
wave_send_once	Transmits a waveform once
wave_send_repeat	Transmits a waveform repeatedly
wave_send_using_mode	Transmits a waveform in the chosen mode
wave_chain	Transmits a chain of waveforms
wave_tx_at	Returns the current transmitting waveform
wave_tx_busy	Checks to see if a waveform has ended
wave_tx_stop	Aborts the current waveform
wave_get_cbs	Length in cbs of the current waveform
wave_get_max_cbs	Absolute maximum allowed cbs
wave_get_micros	Length in microseconds of the current waveform
wave_get_max_micros	Absolute maximum allowed micros
wave_get_pulses	Length in pulses of the current waveform
wave_get_max_pulses	Absolute maximum allowed pulses
UTILITIES
get_current_tick	Get current tick (microseconds)
get_hardware_revision	Get hardware revision
get_pigpio_version	Get the pigpio version
pigpio.error_text	Gets error text from error number
pigpio.tickDiff	Returns difference between two ticks