I have the Google Mirror API's Quick Start for PHP up and running on a Microsoft Azure Website and can communicate with Google Glass.
I had a closer look to the options like the "request/response" example:
case 'insertItemWithAction':
$new_timeline_item = new Google_TimelineItem();
$new_timeline_item->setText("What did you have for lunch?");
$notification = new Google_NotificationConfig();
$notification->setLevel("DEFAULT");
$new_timeline_item->setNotification($notification);
$menu_items = array();
// A couple of built in menu items
$menu_item = new Google_MenuItem();
$menu_item->setAction("REPLY");
array_push($menu_items, $menu_item);
$menu_item = new Google_MenuItem();
$menu_item->setAction("READ_ALOUD");
array_push($menu_items, $menu_item);
$new_timeline_item->setSpeakableText("What did you eat? Bacon?");
$menu_item = new Google_MenuItem();
$menu_item->setAction("SHARE");
array_push($menu_items, $menu_item);
(from https://github.com/googleglass/mirror-quickstart-php/blob/master/index.php)
I am now wondering if it is possible to use the Google Glass Mirror API to scan a QR code.
The idea is to replace the user having to speak a control digit, convert the control digit to a QR code and have the user scan the QR code without having to speak.
Is this possible?
You cannot present a QR Code scanning screen to your user by only using the Mirror API. Nor can you add a MenuItem allowing the user to send back a picture.
But, you can register as a contact, and have your users share with you pictures containing QR Codes.
This is not a very fluid user experience, but it's the only way you could "scan" QR Codes while only using the Mirror API.