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Newsgroups: rec.autosPath: cantaloupe.srv.cs.cmu.edu!das-news.harvard.edu!noc.near.net!howland.reston.ans.net!usenet.ins.cwru.edu!neoucom.edu!wtmFrom: wtm@uhura.neoucom.edu (Bill Mayhew)Subject: Re: electronic odometers (was: Used BMW Question ..... ???)Message-ID: <1993Apr15.150614.8569@uhura.neoucom.edu>Organization: Northeastern Ohio Universities College of MedicineReferences: <1993Apr14.174857.28314@porthos.cc.bellcore.com> <CONRADIE.40.734872761@firga.sun.ac.za> <9833@dirac.physics.purdue.edu>Date: Thu, 15 Apr 1993 15:06:14 GMTLines: 32I consulted with someone working on an electronic odometer. Thedesign was to use a microprocessor based system to write a somewhatofuscated pattern into an EEPROM. The idea was to make the circuitdifficult to program arbitrary values into the EEPROM. Thesecondary purpose, acutally the primary purpose from the standpointof practicality, was to distributed the writes so as to avoidexceeing the maximum number of writes fof the EEPROM being used.The microprocessor also ignored pulses coming from the Hall effectat a rate any higher than 110 MPH so as to make spoofing the readingby bench pulsing at least somewhat undesirable. This was for anautomobile that was not expected to ever exceed 110 MPH inoperation. The case, of course, might not be the same for your1993 RX-7!The ECM modules of some cars do indeed store info about conditionsunder which cars have been operated. Since steering angle andvelocity data, etc is available it would not be difficult tocollect all sorts of interesting demographic information about thedrivers' use of the car. I am not aware of any manufacturercurrently trying to enforce warranty restrictions based on readingout use data from the ECM. While it could be a potential invasionof your privacy for manufacturers to have access to data about yourdriving style, it could also provide valuable information fromactual field use conditions to help engineer more appropriate cars.I personally wouldn't mind the dealer collecting my drivingdemographics as long as it is done in an anonymous fashion.-- Bill Mayhew NEOUCOM Computer Services DepartmentRootstown, OH 44272-9995 USA phone: 216-325-2511wtm@uhura.neoucom.edu (140.220.1.1) 146.580: N8WED
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