GrovePi v0.6.1 GrovePi.Button View Source
Conveniences for working with a button.
Listen for events from a GrovePi button. There are two types of
events by default; pressed and released. When registering for an event the
button will then send a message of {pin, :pressed, %{value: 1} or
{pin, :released, %{value: 0}}. The button works by polling
GrovePi.Digital on the pin that you have registered to a button.
Example usage:
iex> {:ok, button} = GrovePi.Button.start_link(3)
:ok
iex> GrovePi.Button.subscribe(3, :pressed)
:ok
iex> GrovePi.Button.subscribe(3, :released)
:okLink to this section Summary
Functions
Stops the current scheduled polling event and starts a new one with the new interval
Returns a specification to start this module under a supervisor
Invoked when the server is started. start_link/3 or start/3 will
block until it returns
Read the value from the specified pin
Callback implementation for GrovePi.Poller.read_value/2
Starts a process linked to the current process
Stops polling immediately
Subscribes the current process to an event
Link to this section Functions
change_polling(GrovePi.pin(), integer(), atom()) :: :ok
Stops the current scheduled polling event and starts a new one with the new interval.
Returns a specification to start this module under a supervisor.
See Supervisor.
Invoked when the server is started. start_link/3 or start/3 will
block until it returns.
args is the argument term (second argument) passed to start_link/3.
Returning {:ok, state} will cause start_link/3 to return
{:ok, pid} and the process to enter its loop.
Returning {:ok, state, timeout} is similar to {:ok, state}
except handle_info(:timeout, state) will be called after timeout
milliseconds if no messages are received within the timeout.
Returning {:ok, state, :hibernate} is similar to {:ok, state}
except the process is hibernated before entering the loop. See
c:handle_call/3 for more information on hibernation.
Returning {:ok, state, {:continue, continue}} is similar to
{:ok, state} except that immediately after entering the loop
the c:handle_continue/2 callback will be invoked with the value
continue as first argument.
Returning :ignore will cause start_link/3 to return :ignore and
the process will exit normally without entering the loop or calling
c:terminate/2. If used when part of a supervision tree the parent
supervisor will not fail to start nor immediately try to restart the
GenServer. The remainder of the supervision tree will be started
and so the GenServer should not be required by other processes.
It can be started later with Supervisor.restart_child/2 as the child
specification is saved in the parent supervisor. The main use cases for
this are:
- The
GenServeris disabled by configuration but might be enabled later. - An error occurred and it will be handled by a different mechanism than the
Supervisor. Likely this approach involves callingSupervisor.restart_child/2after a delay to attempt a restart.
Returning {:stop, reason} will cause start_link/3 to return
{:error, reason} and the process to exit with reason reason without
entering the loop or calling c:terminate/2.
Callback implementation for GenServer.init/1.
read(GrovePi.pin(), atom()) :: GrovePi.Digital.level()
Read the value from the specified pin.
Callback implementation for GrovePi.Poller.read_value/2.
Starts a process linked to the current process.
This is often used to start the process as part of a supervision tree.
Options
:poll_interval- The time in ms between polling for state.i If set to 0 polling will be turned off. Default:100:trigger- This is used to pass in a trigger to use for triggering events. See specific poller for defaults:trigger_opts- This is used to pass options to a triggerinit1. The default is[]
stop_polling(GrovePi.pin(), atom()) :: :ok
Stops polling immediately
subscribe(GrovePi.pin(), GrovePi.Trigger.event(), atom()) :: {:ok, pid()} | {:error, {:already_registered, pid()}}
Subscribes the current process to an event.