Inventory management robots

A robot managing inventory in a site, the robot comprising:

• a motorized base positioning the robot before a plurality of units of an item organized according to a particular arrangement;
• a retrieval arm retrieving a particular unit off from the particular arrangement;
• a sensory array comprising at least one sensor obtaining (i) a first measure of distance separating a first unit and a last unit in the particular arrangement based on first output from the sensor that captures one end of the particular arrangement and an opposite end of the particular arrangement as a result of aiming the sensor at the first and last units in the particular arrangement prior to the retrieval arm retrieving the particular unit, and (ii) a different second measure corresponding to a size of the item based on second output resulting from aiming the sensor at the retrieval arm after retrieval of the particular unit off from the particular arrangement with the retrieval arm;
• and
• a processor dynamically tracking a count for a number of units in the particular arrangement from the first measure of distance, that is obtained directly from the first output of the sensor, the size of the item, that is obtained directly from the second output of the sensor, and exclusive of data that is stored in a database or another data source.

A device comprising:

• a sensory array;
• and
• one or more processors configured to:
• aim a sensor of the sensory array at first and last items of a plurality of items in a particular arrangement;
• detect a first unique feature about a side of the first item that is within the sensor field-of-view, and a second unique feature about a side of the last item that is within the sensor field-of-view based on first output from the sensor;
• measure a distance between the first and last items in the particular arrangement based on separation between the first unique feature and the second unique feature in the first output from the sensor, wherein measuring the distance is performed exclusive of information that is stored within a database and without the device accessing the database;
• aim the sensor at one item or two adjacent items in the particular arrangement;
• measure a size of a particular item in the particular arrangement based on second output from the sensor, wherein the second output comprises a dimension of the one item or a distance between unique features of the two adjacent items, wherein the particular item is one item from the plurality of items, and wherein measuring the size is performed exclusive of the information that is stored in the database and without the device accessing the database;
• and
• track inventory of the plurality of items in the particular arrangement by deriving a number of items in the particular arrangement from the distance between the first and last items that is measured directly from the first sensor output, the size of the particular item, that is measured directly from the second sensor output, and exclusive of data that is stored in a database or another data source.