Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!zaphod.mps.ohio-state.edu!rphroy!rinhp825.gmr.com!vbreault From: vbreault@rinhp825.gmr.com (Val Breault) Newsgroups: sci.electronics Subject: Re: Digital dash (was: Inductive pickups.) Message-ID: <54724@rphroy.UUCP> Date: 31 May 91 16:21:23 GMT References: <1970@ole.UUCP> <1991May30.151040.50@cmkrnl.uucp> <1991May31.143333.16729@ms.uky.edu> Sender: news@rphroy.UUCP Reply-To: vbreault@gmr.com Organization: General Motors Research Lab. Warren, MI Lines: 25 Nntp-Posting-Host: rinhp825.gmr.com ...... > An interesting idea- how did this mechanical setup work? In the olden days, when the only electronics on a car was the radio, the cruise control worked this way: The speed signal was carried by the speedometer cable to a mechanical device that was positioned under the hood. Another speedometer cable carried the speed signal from that device to the speedometer itself. The device compared the desired speed against the actual speed and created an error signal using manifold vacuum. The vacuum was supplied to a diaphragm that actuated the throttle. If you get one of those buggers you can gut it and salvage some nifty stuff. The housing with it's bearings and speedometer cable connectors will get the speed signal to the existing speedometer. With the mechanical comparitor out of the way, you'll have plenty of room to mount your magnetic pickup. ------------------------------------------- Val Breault - vbreault@gmr.com The opinions expressed by the author do not necessarily reflect the position of the General Motors Research Laboratories or the General Motors Corporation.