alternative to RFID

[REVCAM_Bob]

I need an alternative to RFID to i.d. a fixture and transfer that fixture identification to a computer...
thought about mulitple dowel pins sticking out of the fixture plate that could push against contact switches... (just as one option).... need maybe 1000 separate i.d.'s maximum.....

Anyone have any other ideas?

Thanks!

[beege]

bar code and reader?

[Geof]

Proximity detectors, small ones.

Mount them in an array of 3 by 4 and then have an aluminum block on the fixture that comes up close to this array. Bore holes in this block in line with the detectors you do not want to activate. Twelve detectors give you much more than 1000 ids so you possibly could use the spares for malfunction detection.

[REVCAM_Bob]

So use the proximity sensors like binary i.e. 64 32 16 8 4 2 1 etc... or is there a fancier way?

[beege]

Maybe think along the lines of punched tape, like a parity bit, stop bit and data bits?

[samco]

Our K&T has a 'barcode' system iirc it has 12 rings that slide by 12 fingers to read the tool.

http://electronicsam.com/images/Kand...gerspindle.JPG

[Al_The_Man]

Originally Posted by REVCAM_Bob So use the proximity sensors like binary i.e. 64 32 16 8 4 2 1 etc... or is there a fancier way?

I guess a little more has to be known about the environment, is there machining? Coolant? etc.
This will be a big deciding factor as to the sensing elements.
Al.

[Geof]

Originally Posted by REVCAM_Bob So use the proximity sensors like binary i.e. 64 32 16 8 4 2 1 etc... or is there a fancier way?

Something along those lines; 10 sensors give you 1024 discrete numbers.

I figure you can probably make the sensor mounting coolant proof by potting them in plastic with just the tips exposed. They could be inset into the baseplate with the blocks in the fixture; this way they are automatically cleaned off when things are cleaned to load the fixture and there are no moving parts. Also when the fixture is in use they are covered and protected from chips.

[Al_The_Man]

Originally Posted by REVCAM_Bob So use the proximity sensors like binary i.e. 64 32 16 8 4 2 1 etc... or is there a fancier way?

Going this way is a viable solution as Geoff pointed out a method.
If you do use something like this, I would do a 'qualifying' check before the jig is loaded.
IOW, the code should read zero with no jig present, otherwise it could be a false trip/reading and could be set to cause an alarm.
Al.

[REVCAM_Bob]

Yes, the possibility exists of metal chips etc.... hmmm maybe I need to think this through a little more....

[Geof]

Originally Posted by REVCAM_Bob Yes, the possibility exists of metal chips etc.... hmmm maybe I need to think this through a little more....

Like I suggested, put the sensors in the base and they will be cleaned of chips during loading of the fixture and protected by it when in use.