Abstract:
A method of inventory management is described. Upon activation of a button on a wireless device, the wireless device having a light source and a transceiver with a unique media address corresponding to a unique product, the device broadcasts a first signal including an order command and the unique media address by the transceiver via a wireless medium. A central controller then receives the first signal, identifies the unique media address included in the first signal, and using a database, identifies the unique product associated with the unique media address.

Description:
PRIORITY CLAIM 
   This application is a Continuation application of U.S. patent application Ser. No. 09/801,203, filed on Mar. 7, 2001, now U.S. Pat. No. 6,838,977, which is incorporated by reference herein. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to an apparatus for improving manufacturing management using a wireless device. 
   The manufacturing process requires careful logistical planning to produce products as quickly as possible. An issue that may arise on a manufacturing floor or an assembly line is the constant need to replenish parts used in the manufacturing process. This need presents logistical difficulties in that each worker or work station may have only limited space to store the necessary parts on an assembly line. Moreover, each worker or work station may have a different number of parts and thus run out at different times on the manufacturing floor. Accordingly, the bulk of the parts used on the manufacturing floor or assembly line may be located offsite at a central parts facility. Such parts must be transported from the central parts facility to each worker or workstation on a case by case basis. 
   Prior art systems have attempted to solve this problem by providing a wired electronic notification system for each worker or work station. Upon realizing that a shortage of parts will occur in the near future, the worker activates the notification system to notify the central parts facility. The wired system then ascertains the identity of the worker and the type of parts needed. 
   The disadvantages of the wired electronic system are many. Fashioning such a system in a wired fashion adds an additional level of complication to an already complex manufacturing system. Moreover, the wired system lacks the flexibility to be quickly reconfigured based on the changing layout of a manufacturing facility. 
   SUMMARY OF THE INVENTION 
   Therefore, the proposals of the related art fail to comprehensively overcome the problems discussed above and other related problems. Advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. 
   The present invention provides an efficient wireless-based call replenishment system that is designed to order replacement parts on a real-time, as-needed basis. This system makes the manufacturing process easier by eliminating the wiring necessary to establish the prior art wired system. Such a system may also be easily reconfigured based on the changing layout of the manufacturing process. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a block diagram of the wireless pendant, which is an embodiment of the present invention. 
       FIG. 2  illustrates a flowchart illustrating an operation of a system of the present invention. 
       FIG. 3  illustrates a block diagram of a system implementing the present invention. 
   

   DETAILED DESCRIPTION 
   As shown in  FIG. 1 , an embodiment of the present invention consists of a wireless pendant  10  that is designed to order replacement parts in the manufacturing process in a simple and efficient manner.  FIG. 1  illustrates a wireless pendant  10  with a body  12 , a push-button  16  and an LED  14 . 
   Pendant Modes 
     FIG. 2  illustrates the general operation of the wireless pendant system. 
   When activated by the user by pressing the push-button  16  (Step  1010 ), the wireless pendant  10  will indicate to the user it has been turned on by beginning to blink the LED  14  (Step  1020 ). In one embodiment, a blink rate of 1 Hz at a 20% duty cycle (200 ms on) is proposed. Based on the activation the wireless pendant  10  will “wake up” and send identification data over a wireless network. In one embodiment, the wireless network is based on the IEEE 802.11 protocol. This data will be used to uniquely identify each wireless pendant  10 . The unique identification (possibly the MAC address) will be looked up against a database to determine what component and location the activated wireless pendant  10  represents (Step  1030 ). 
   Upon receipt of the data the wireless network will reply to the wireless pendant  10  that its request has been accepted (Step  1040 ). In one embodiment, once the reply is received the wireless pendant  10  will reduce the blink rate of the LED  14  to 0.5 Hz at 10% duty cycle (same 200 ms on) (Step  1050 ). It is anticipated that the time from initiation to confirmation may be 5 seconds or less. It is assumed that at this time (between Initiation and Acknowledgement) the wireless pendant  10  is awake and waiting for the network to reply to it. If the wireless pendant  10  has to stay awake for an extended period of time battery life may be reduced. 
   Once the wireless pendant  10  has received the acknowledgement that the wireless network has received the request the wireless pendant  10  may go to into a power save mode. At this point the system will put the request in the queue and the wireless pendant  10  status will not change until a forklift driver retrieves the request from the queue for material delivery or the requestor pushes the button again to cancel the initial request. 
   After acknowledgement, it is assumed that wireless card and micro can sleep (power save mode) and poll the wireless network for data (once per N minutes) for any updates. The on time during for polling may be less than 5 seconds. If it is longer battery life may be reduced, but this may be traded against a longer polling period. 
   Once a driver takes the request off of the queue there will be an update on the status in the network to Delivery Pending. The Delivery Pending information will be sent to the wireless network and during the next poll of the network by the wireless pendant  10  it will retrieve the updated status (Step  1060 ). In one embodiment, the LED  14  blink will then become a double blink at a 0.25 Hz rate (Step  1070 ). 
   After receipt of the Delivery Pending status the wireless pendant  10  will go back to a polling mode and wait for fulfillment command. 
   Upon delivery of the requested material the driver will change the request status to fulfillment by using the forklift terminal (Step  1080 ). The information from the forklift terminal will be sent to the system and a fulfillment message will be sent to the wireless network for retrieval by the wireless pendant  10  during its next poll. Upon the next wireless pendant  10  poll the wireless pendant  10  will receive the fulfillment message from the wireless network (Step  1090 ), shut the LED  14  (Step  1100 ) and shut down. 
   The requester may cancel an acknowledged request prior to the driver picking it up off of the queue. If the request is in the acknowledgment phase on the network and on the wireless pendant  10  the requestor may cancel it by pressing the button again. When pressed the wireless pendant  10  will send a message to the wireless network again and the network, perhaps knowing that particular wireless pendant  10  had a request in the acknowledgement phase, will reply to the wireless pendant  10  that the request has been canceled. Upon receipt of that reply the wireless pendant  10  will shut the LED  14  and return to its quiescent state. 
   Once a request has been picked up off the queue the request will have a status on the network of Delivery Pending, but due to the latency of the polling technique the wireless pendant  10  would still be in the acknowledgement phase. At this point the request can no longer be canceled. If the requestor did try to cancel at this point the network would respond with a message that would update the wireless pendant  10  status LED  14  indicating that the driver was in route (Delivery Pending). 
   A graphic depicting flash rates for each state is presented below: 
   
     
       
             
             
             
           
         
             
                 
                 
             
             
                 
               Phase 
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               Initiation 
               
                 
                           
                   
                       
                       
                   
                 
               
             
             
                 
                 
             
             
                 
               Acknowledgement 
               
                 
                           
                   
                       
                       
                   
                 
               
             
             
                 
                 
             
             
                 
               Delivery Pending 
               
                 
                           
                   
                       
                       
                   
                 
               
             
             
                 
                 
             
             
                 
               Fulfillment 
               
                 
                           
                   
                       
                       
                   
                 
               
             
             
                 
                 
             
             
                 
               Cancellation 
               
                 
                           
                   
                       
                       
                   
                 
               
             
             
                 
                 
             
           
        
       
     
   
   In an alternative embodiment, an speaker may be installed in place of or in addition to using an LED  14 . This would provide aural confirmation of the status of the request in the same manner as the LED  14  provides visual confirmation. 
   Wireless Pendant Physical Overview 
   In one embodiment, the wireless pendant  10  will be comprised of a housing, a serial wireless network card, an antenna, an activation button, an indicator LED  14  (on a flex or PCB) a “carrier” PCB and a battery pack. In one embodiment, a portable unit can be made using disposable batteries. The polling period N may be increased if needed to extend battery life. The polling period will determine the latency of the wireless pendant  10   s  status updates. 
   The “carrier” PCB will contain the circuitry to regulate/condition the supplied battery power and be the interface between the button, LED  14 , processor and wireless card. The “carrier” PCB will have a battery threshold circuit to send a signal to the wireless card (or processor) to indicate that battery power is low and that the wireless pendant  10  requires service. 
   The wireless pendant  10  assembly may be a stack up with the battery on the bottom followed by the carrier PCB, the wireless card and then the antenna. The button/led circuit would be minimized (to reduce RF interference) and placed at the top of the stack. Based on this, the wireless pendant  10  will have an orientation associated with its RF performance, the accessibility of the button and the visibility of the LED  14 . 
   Call Button 
   The Call Button can be broken into four major subparts, involving the design and construction of 
   Call Button Hardware 
   Call Button Firmware Software 
   Call Button Message Server Software 
   Call Button Application-layer Server 
   Call Button Hardware—this is the design and assembly of the button itself. The design consists of an enclosure, microcontroller, button, radio card, battery, and associated circuits on a PC In one embodiment, a Serial OEM wireless radio card manufactured by Symbol Technologies, Inc. (the assignee of the present application) is the key component in this design, because, unlike our other radio cards, it also contains a protocol stack. Having this all on one card saves power and money, of critical importance for his project. In a further embodiment, the card utilizes the 1 Mb frequency-hopping protocol. 
   Call Button Firmware Software—these are the commands issued by the microcontroller to turn on/control the radio card and button LED  14 , and send messages upwards to a Message Server about status changes. To conserve power, the entire button-radio, microcontroller, etc., will turn off for periods of time, with external timing circuits firing the blinking LED  14 . 
   Call Button Message Server—This is a layer of software, residing on a wired LAN, that accepts messages from Call Buttons, and posts to the Application-layer Server. In one embodiment, to conserve power, UDP, and not TCP, was chosen as the protocol to implement. This is because UDP is a connectionless protocol, and hence we will not waste power maintaining connections (e.g., sockets) at the Call Button end. There is not guaranteed acknowledgements with UDP, however, so this function is built into the messaging. 
   Call Button Application-layer Server—The application-layer Server is also a piece of software that resides on an Server. The purpose of this piece of software is to provide options to communicate with various different applications. Though GE-Fanuc&#39;s Cimplicity is well established in the auto industry, with over 50% market share, many other manufacturing environments have workers with limited WIP inventory, and hence need resupply during their shift. These environments would also benefit from a Call Button approach. Having an application-layer server separate from the Message Server allows the flexibility to address various market segments. The call button application-layer server may also be OPC compliant. 
   Configuration of Wireless Pendant System 
     FIG. 3  illustrates a system of multiple wireless pendants illustrating the advantages of the present invention. Shown in  FIG. 3  is an overhead view of a factory floor  30 , which may be configurable into many different layouts depending on the assembly activities taking place therein. The factory floor  30  has a plurality of access points  32   a ,  32   b ,  32   c ,  32   d  installed at various points above the floor  30 . These access points  32   a ,  32   b ,  32   c ,  32   d  are then wired to a local area network (not shown). The access points  32   a ,  32   b ,  32   c ,  32   d  communicate with the plurality of wireless pendants  34   a ,  34   b ,  34   c ,  34   d  that are strategically situated throughout the factory floor  30 . The wireless pendants  34   a ,  34   b ,  34   c ,  34   d  may be secured in place using VELCRO or other hook and loop type fastener at the appropriate locations on the factory floor  30 . Thus, when the configuration of the factory floor  30  is altered, the wireless pendants  34   a ,  34   b ,  34   c ,  34   d  may also be easily reconfigured. 
   Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.