Also try Coin controls in the UK or Mars electronics. Joe -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Roger, in Bangkok Sent: 29 July 2003 07:48 To: PICLIST@MITVMA.MIT.EDU Subject: Re: [EE]: Info on Coin-Comparators is needed. Search for coin rejecter or coin acceptor. Asahi-Seiko in Japan and National Rejecters in Germany are among the major manufacturers. These days the coins' profiles are "taught" or loaded into the coin mechanism electronics rather than using a reference coin. There are very cheap mechanisms from China that use a reference coin, but they only accept based on physical comparisons. Regards/Roger, in Bangkok -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Bob Axtell Sent: Tuesday, 29 July, 2003 1:25 PM To: PICLIST@MITVMA.MIT.EDU Subject: Re: [EE]: Info on Coin-Comparators is needed. The ones I am familiar with work primarily on physical effects. Its like comparing the effect of a metallic object in an resonant (oscillator) circuit. One coin is placed in a reference coil, and its characteristics are learned (how much this coin changes the frequency etc). The one to being tested falls through another coil; if its fall causes effects identical (within limits) to the reference, the coin is accepted. Most of the work is spent slowing the fall of the coin so the effect can be carefully examined. Having designed metal detectors in my youth (er.. day before yesterday) I have always been fascinated by how they work so well. US coins (like most coins) no longer have ANY precious metal, and in order to obtain an effect similar to real coins, are layered with an inner core of copper to more closely match the solid, precious-metal coins they mimic. Try looking up http://www.windtrax.com/featured_products/ --Bob At 08:40 AM 7/29/2003 +0400, you wrote: >Guys, >has anybody good links to practical aspects of the coin-comparators >design (schematic, theory etc.)? I googled, but didn't find anything. > >Thanks in advance. >Mike. > >-- >http://www.piclist.com#nomail Going offline? Don't AutoReply us! email >listserv@mitvma.mit.edu with SET PICList DIGEST in the body --------------- NOTICE 1. This account can accept email & attachments up to 10M in size. 2. Federal Monitors: At request of client, some attachments are encrypted. Please DO NOT delay traffic; please reply with credentials for password. -------------- -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body