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DISPENSING THE GOODS, EMBEDDED STYLE

by Todd Rytting

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In July of 1998, emWare joined several other companies in a meeting at SAP Labs. SAP described a demonstration they wanted to include in the 1998 Developerıs Conference in August. At the previous yearıs conference, SAP demonstrated an Internet-enabled vending machine. However, the technology that was demonstrated was not economically feasible for real-world implementation. A 32-bit DEC computer had been installed in the base of a vending machine to deliver the Internet connectivity.

SAP asked emWare to participate with other companies in a demonstration for the 1998 Developerıs Conference that showcased a more realistic approach for networking embedded devices. After four weeks of hard work and coordination on many different fronts, the Internet-networked vending machine shown in Figure 1 was demonstrated, live and "in-machine."

Figure 1ıHereıs how the system was set up for the SAP Developerıs Conference demonstration

emWareıs EMIT device-networking software Internet-enabled vending machines with an 8-bit MCU. The vending machine was connected via serial cable to a COM port on a desktop PC running emGateway.

emWare served as the embedded-system developer for this project and created a JAVA GUI, using emObjects, for controlling the vending machines across the Internet using a standard web browser.

Abaco and SAP used the EMIT Access Library (EAL) to remotely access the data in the vending machine and move it into SAPıs R3 product (a software product that manages and integrates all phases of business operation). IBM used its voice-recognition software engine and the EAL to control the vending machine from a phone call into a remote telephony server.

SAP engineers used Micronıs Microstamp wireless ID badge recognition system and EAL to authorize coinless dispensing of cans to holders of authorized badges. The vending machine logged the identification of the person who dispensed the can for eventual tracking by R3.

Sybase and SAP then used the Palm III PDA to monitor and control the vending machine with infrared communication. The Palm Pilot would vend cans, interrogate the machine, and download statistical information that could later be hot-synched into R3.

The demonstration showcased an embedded device with an inexpensive 8-bit MCU that was network-enabled with a serial connection, accessed and controlled from the Internet, and managed using a variety of sophisticated user interfaces.

Once we had an 8-bit MCU with an embedded application integrated with emMicro, all the user interfaces could connect to it through emGateway. No changes were required to the embedded device code to create, add, change, or modify the user interfaces. An example of the browser-based user interface is shown in Photo 1.

Photo 1ıThe web browser-based user interface panels allowed vending of cans, monitoring of status and downloading of historical data.

Ideally, emMicro would be embedded in the MCU that is on the OEM vending machine controller. Because time was extremely short for this demo, we used one of the SDK reference boards that was included in the EMIT SDK. The SDK board took control of the front-panel buttons, door-open sensor, can-drop sensor, and a vend-override jumper.

We wrote an embedded application for the SDK reference board that intercepted a button push, then checked to see if an authorized variable in the embedded application had been set from emGateway. If the variable had been set (indicating an authorized request for a can), a relay from the MCU activated an actual vending machine button push and the vend override jumper, causing the proper can to drop. This "authorized variable" could be set via emGateway from the ID badge system, a web browser, the speech recognition server, or directly from the Palm III.

We also used the spare serial port on the SDK reference board to communicate with the OEM controllerıs serial port using the vending industry DEX protocol. When a client requested a download of the machine status, that request would be passed on to the OEM controller through the SDK reference board. The embedded application would capture the DEX data download and store it in an embedded variable array that was available to a client via emGateway.

For a production implementation, the OEM controller designer could add emMicro to his embedded application and then burn a new MCU or re-flash memory the existing one, and use the existing serial port to communicate with emGateway. The cost of the hardware required to network-enable the vending machine is an MCU with new code and a serial connector for emGateway. The emGateway PC would be in a central location in a region and, via modem, could individually dial-up and connect with many vending machines within a designated local calling zone.

The vending machine demonstration clearly illustrates how tools like EMIT can be used to provide an embedded-device networking solution. We havenıt provided any of the actual vending code for you to experiment with because not many people have a vending machine at their disposal. Instead, the examples in the rest of the article illustrate the same functionality using either the EMIT SDK reference board (available for free) or your own hardware as an experimentation platform.

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