http://stackoverflow.com/questions/39938804/a-component-responding-to-another-components-action

components.my-button.js

import Ember from 'ember';

export default Ember.Component.extend({
});

components.my-select.js

import Ember from 'ember';

export default Ember.Component.extend({
  stateList: [{'label': 'New Jersey','value': 'NJ'},{ 'label': 'New York','value': 'NY'}],
  state:'NY',
  selectedState: Ember.computed('state', function(){    
    return this.get('stateList').findBy('value',this.get('state'));
  }),
  actions:{
    setSelectedState(selectedVal){      
      this.set('state',selectedVal.value);
    }
  }
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  data:'a',
  actions:{
    onSelectChange(dataFromSelect){
      this.set('data',dataFromSelect);
    }
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
{{my-select }}
{{my-button }}
<br>
{{outlet}}
<br>
<br>

templates.components.my-button.hbs

<button> My-Button</button>
{{yield}}

templates.components.my-select.hbs

<div id="ember-basic-dropdown-wormhole">
{{#power-select 
    options=stateList
    searchField="label"
    selected=selectedState
    onchange=(action 'setSelectedState')
    as |state|
}}
    {{state.label}}
{{/power-select}}
</div>
{{yield}}

twiddle.json

{
  "version": "0.10.5",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.4.6",
    "ember-template-compiler": "2.4.6",
    "ember-testing": "2.4.6"
  },
  "addons": {
  "ember-power-select":"0.10.11"
  }
}