RFID tags are a great solution. The only problem is with the reader. You ne= ed to make sure that the reader can handle a multiple tag situation, i.e. w= hen two cats are in range of the reader. If the two tags can be read, then a logical outcome can be computed. Just $0.02 extra, Jean-Paul N1JPL > On Jan 3, 2016, at 3:50 PM, John Ferrell wrote: >=20 > Have you talked to the cats? >=20 > Sorry, I just could not resist... > I only have one cat and he teaches me what I need to know. >=20 > On 1/2/2016 1:08 PM, rossano gobbi wrote: >> Speaking of cats... what would you people do in this case? >>=20 >> I've got 4 of them, let's call them A,B,C and D. Cat A must eat a specia= l food, let's call it "1". Cats B and C must eat another special food I'll = call "2". While cat A's diet must be absolutely strict otherwise really bad= (for us living with him) things happen, cat B and C's diet can tolerate ex= ceptions. Cat D could eat whatever he wants but we'd like him eating his no= rmal food "3", instead of the other two. Needless to say, everyone, except = B, likes better the food that isn't his. >> We usually do this procedure by hand, by feeding them only once or twice= a day and watching them, but doing the cat-police is getting more and more= annoying so I'd like to introduce some level of automation... >> Any hint?:-) =20 >> A late happy new year to all of you! >>=20 >> Rossano >=20 > --=20 > John Ferrell W8CCW > Julian NC 27283 > It is better to walk alone, > than with a crowd going the wrong direction. > --Diane Grant >=20 >=20 > --=20 > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .