# MotorHat
[![Build Status](https://travis-ci.org/matthewphilyaw/motor_hat.svg)](https://travis-ci.org/matthewphilyaw/motor_hat)

Implementing the [motor_hat](https://github.com/adafruit/Adafruit-Motor-HAT-Python-Library) library in elixir for a project. Initial support will be for DC motors only, but will try to expand to a complete functional clone (no pun intended) of this library for elixir plus have a few ideas to extend it.

It's important to note that I said a functional clone, in so far as I am aiming to provide a similar API as closely as I can, but the internals work a bit different - Elixir is not python.

## Installation

If [available in Hex](https://hex.pm/docs/publish), the package can be installed as:

  1. Add motor_hat to your list of dependencies in `mix.exs`:

        def deps do
          [{:motor_hat, "~> 0.6.0"}]
        end

## configuration

MotorHat needs to be configured before run. `config/dev.exs and config/test.exs` are good examples of how to configure the application for your project.

Typical configuration
``` Elixir
config :motor_hat,
  boards: [ # one or more boards to configure and start
    [ 
      # key to use to look up board for calls like get_dc_motor which uses 
      # this key to find the board
      name: :mhat,
      devname: "i2c-1", # busname, i2c-1 is common on the raspberry pi
      address: 0x60, # address on i2c,
      # motor config may change in the future right now in only supports
      # dc motors not entirely happy with this.
      motor_config: {
        :dc, # dc instead of stepper
        [:m2, :m3] # motor positions to create, can be :m1 - :m4
      }
    ]
  ]
```

There is one key that is optional which is i2c: and it's used like this

```Elixir
config :motor_hat,
  i2c: MotorHat.Test.I2cFake, # <- optional do not populate normally, it defaults to I2c
  boards: [ # one or more boards to configure and start
    [ 
      # key to use to look up board for calls like get_dc_motor which uses 
      # this key to find the board
      name: :mhat,
      devname: "i2c-1", # busname, i2c-1 is common on the raspberry pi
      address: 0x60, # address on i2c
      # motor config may change in the future right now in only supports
      # dc motors not entirely happy with this.
      motor_config: {
        :dc, # dc instead of stepper
        [:m2, :m3] # motor positions to create, can be :m1 - :m4
      }
    ]
  ]
```

i2c: allows you to swap out the I2c module which normally is the Elixir_Ale module. In this case we have redefined it to MotorHat.Test.I2cFake, which is used in the tests to mock up the I2c calls.

## NOTE
if for any reason you stop the shell using ctrl-c or ctrl-g q, the motors if running will continue to run. 
Basically when you interact with the motor hat board you are giving it commands to run via I2c,
which happens outside of elixir there are no continuos command sent to keep the motoring running and as long as the
motor hat board has power it will continue to run the last command given

if this happens, simply running `mix` will stop the motors as part of the inialization of the MotorHat app.