US 11,940,320 B1
Compressing load signal transmissions
Sarang Sandeep Bhadsavle, Seattle, WA (US); Alexander Eugene Choi, Seattle, WA (US); Graham Cyril Jordan, Edmonds, WA (US); Paul Eugene Munger, Seattle, WA (US); Robert M. Riggs, Winthrop, WA (US); Benjamin Hong Yee, Seattle, WA (US); and Matthew Zimmer, Seattle, WA (US)
Assigned to Amazon Technologies, Inc., Seattle, WA (US)
Filed by Amazon Technologies, Inc., Seattle, WA (US)
Filed on Jun. 25, 2021, as Appl. No. 17/358,617.
Int. Cl. G01G 19/414 (2006.01); G01G 23/18 (2006.01); G06Q 10/087 (2023.01)
CPC G01G 19/4144 (2013.01) [G01G 23/18 (2013.01); G06Q 10/087 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for tracking items in a materials handling facility, wherein the materials handling facility comprises:
a computer system;
a storage system comprising:
a platform having a plurality of items thereon; and
a plurality of load sensors disposed beneath the platform, wherein each of the plurality of load sensors comprises:
a battery;
a load cell configured to generate load signals corresponding to a load; and
a wireless transmitter configured to transmit the load signals to the computer system; and
wherein the method comprises:
generating, by a first load sensor of the plurality of load sensors, a first load signal corresponding to a load applied to the first load sensor at a first time;
determining, by the first load sensor, an estimated value of the load applied to the first load sensor at the first time based at least in part on an estimated value of a load applied to the first load sensor prior to the first time;
calculating, by the first load sensor, a first error based at least in part on a difference between the load applied to the first load sensor at the first time and the estimated value of the load applied to the first load sensor at the first time;
determining, by the first load sensor, that an absolute value of the first error exceeds a threshold;
in response to determining that the absolute value of the first error exceeds the threshold,
selecting, by the first load sensor, at least a first set of bits based at least in part on a difference between the absolute value of the first error and the threshold, wherein the first set of bits is encoded according to a binary code,
wherein a first digit of the first set of bits is one,
wherein the second digit of the first set of bits is zero if the value of the first error is positive,
wherein the second digit of the first set of bits is one if the value of the first error is negative, and
wherein a last digit of the first set of bits is one;
transmitting, by the first load sensor to the computer system, at least the first set of bits;
determining, by the computer system, a value of a change in load on the platform based at least in part on the first set of bits; and
identifying, by the computer system, at least one item based at least in part on the change in load.