elixir_mlx90640 v0.1.1 Mlx90640 View Source
elixir_mlx90640
provides a high level abstraction to interface with the
MLX90640 Far Infrared Thermal Sensor Array on Linux platforms.
Link to this section Summary
Functions
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
Start and link the Mlx90640
GenServer
Link to this section Types
Link to this section Functions
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
GenServer
is 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/2
after 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
.
start_link(pid(), [{:frame_rate, frame_rate()}], [term()]) :: GenServer.on_start()
Start and link the Mlx90640
GenServer.
receiver
is a process that will receive messages on each frame captured by
the sensor.
frame_rate
is the (approximate) number of frames per second that the sensor
will capture. Valid values are 1, 2, 4, 8, 16, 32, and 64. The default is 2.
Higher values might require a faster I2C baud rate to be configured in Linux.
The receiver
process will receive, for each frame captured by the sensor, a
message like %Mlx90640.Frame{ data: data }
, where data
is a list of rows,
and each row is a list of pixel temperature measurements, expressed as float
numbers indicating the temperature in Celsius degrees.
Under normal conditions, there should be 24 rows of 32 pixels each, but in case of corrupted data frames there might be less.
Gracefully stops the Mlx90640
GenServer.