Barcode Scanner

John Burrow

I have a model railroad where a BS2P is·polling a network of RFID readers to detect locomotive movement.

I would like to add barcode reading. I have seen a system (manufactured by Z-Stuff) where a barcode is placed under a locomotive or freight car, and·is then read by a small sensor placed between the rails when the train passes by. This is the sensor http://www.z-stuff.net/DZ-1205.htm

I assume the sensor is reading the high and low light reflections from the white and black striped bar code.

Before I go off and go all the hard work, has anyone done this already? I'm starting from nowhere, so any information about the hardware would be useful.

Thanks, John Burrow

Phil Pilgrim (PhiPi)

Those look like simple reflective optosensors without any inherent decoding. So your Stamp will have to do the decoding for you. Since BASIC Stamps are single-task devices, you won't be able to monitor more than one sensor at a time. Properly configured, though, it may be easy to poll round-robin style for the beginning of a barcode, then decode whichever one has started.

You might look at the "include.bs2" source code (attached below) for the Parallax Scribbler. It has a routine for reading simple serial barcodes that the bot passes over. For this kind of barcode reading to be successful, the locomotive will have to be moving at a fairly constant rate without stopping.

-Phil

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