Post by thread:Button Cell ID tags

In message <spam_OUTm0ruGcw-000DCnCTakeThisOuTdopey.me.iastate.edu>, you write: >This may be PIC related... > >I went to the MegaZone in Morecambe last night, it is a laser gun game >arena, like QZar and Laser Quest. Normally you are known as 'Player 1' >etc., but if you purchase club membership you get your own name stored on >the computer to identify you. To activate this feature you are given a tag >which looks exactly like a button cell (or lithium battery). You press the >cell against two contacts (centre and edge, like + and - contacts for a >power cell) and somehow the cell returns a unique code. One of the cells >was manufactured by Dallas. How do they work? > The Dallas part is probably one of their "Silicon Serial Numbers" (basically a serial ROM), which uses Dallas' one-wire bus. This is a novel bus which uses a single wire for power, clock and data. Interesting devices, these. While we're on the subject, does anyone have PIC code for talking to this bus? The protocol looks to be a bit on the complicated side. :-) --Monty =============================================================================== .....mhbrekkeKILLspam@spam@iastate.edu | "You don't have to thank me. I'm just trying brekkeKILLspamdopey.me.iastate.edu | to avoid getting a real job." | --Dave Barry

Monty W. Brekke (.....brekkeKILLspam.....dopey.me.iastate.edu) wrote: >The Dallas part is probably one of their "Silicon Serial Numbers" > .... >does anyone have PIC code for talking to this bus? The protocol looks >to be a bit on the complicated side. :-) Monty: It's not complicated at all, although you probably want your PIC to be running at some real clock speed (like 4 MHz -- I've done it at 32 KHz, but it wasn't fun). You should get a copy of the Touch Memory Databook from Dallas if you're interested in these parts. -Andy -- Andrew Warren - EraseMEfastfwdspam_OUTTakeThisOuTix.netcom.com Fast Forward Engineering, Vista, California