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For setting up the zone system and for debugging it, I've built a little handy tool: The "I/O analyze device".
This device has all in- and output functions of the wheelchair. But instead of driving around on the track, it just displays the data that it receives - and you can generate the data, that either the wheelchair or the zone system would transmit. So, this gadget can either simulate the zone system, or the wheelchair, that drives in the zone system. Or, you can use it for just "listening" to the data traffic, that occurs between zonecontrollers and wheelchair.

 

Besides all the switches, one of the most important part of the device is its LCD screen. And to have the letters displayed in the most ideal contrast, there is a contrast poti at the lower side of the housing.

 

The main selector on the left side, lets you power up the device and decide, in which mode it will run. You can use the gadget as:

- RFID scanner
- Infrared receiver
- Infrared transmitter (using the RC5 protocol)
- Floor scanner

On the picture below, it scans RFID-tags. On the display, you can see a typical number of a Conrad RFID. These are 5 bytes, written down as hex numbers. The RFID scanner from Conrad always sends an "R", before it sends the 10 hex numbers. Unfortunately, Conrad RFID readers are not compatible with RFID-tags, distributed by other companies. Even if they work on the same frequency.

 

Below the selector switch, there are two potis, which are only used in the IR transmit mode.

 

If the device runs in the IR transmit mode, it sends RC5 codes, if you push one of the buttons below the display. To generate the desired code, you have to use the potis on the left. With one, you can select the address. With the other, you can select the command that should be sent.

RC5 is a protocol to remote control TV's, stereos and other consumer electronics via Infrared. It always consists of one number as device address (address "1" is for television, for instance) and of one number as command (command "1" would switch the TV to the first channel).

I find it somehow funny, that this device can also be used as a TV remote control.

 

On the top of the device, there's a small window for the IR transceiver.

 

This is the bottom of the gadget. In the middle, there are four LED's - they are lighting the floor in the scanner mode. A photo diode (the black point between the LED's) detects the exact gray level of any floor. This is useful, because with this you can decide, whether to use black or white adhesive tape as track.

The shiny foil left to it, is the Photoelectric Diamond Grade retro reflecting material, with which you can switch the zone lasers.

 

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