The early 2-pin style is a dry contact next to a spinning round magnet. Round magnets have 8 poles, which means the contact closes 8 times per revolution. The pinion is geared to about 1000 rotations per mile, so that's 8000 pulses per mile.
One side of the switch is grounded and the other is pulled to 5V by the ECU. When the switch closes, the signal goes low. The 3-pin style is an electronic hall-effect sensor replica of the 2-pin style. The output is the same (8000 pulses per mile). The 3rd pin is a 5 or 8V supply voltage. You can use the 3-pin style in a car with a 2-pin sensor by adding the extra supply line. The 8V feed to the HEP sensor is usually what is used. The only problem is that there is no version of the 3-pin style sensor that can accommodate a speedometer cable. More here: http://minimopar.knizefamily.net/speedsensor.html Russ On Mon, 2007-05-28 at 23:56 -0500, [EMAIL PROTECTED] wrote: > Not sure about your question, but I thought about buying one of this guys > RPM window switches for the same thing... > http://www.harlan-engineering.com/store/store.html > > I have one of his shift lights and it is awesome. He does very good work. > > > Does anyone know how the speed sensor really works? Like is it a magnetic > > pulse, or is it like a mini voltage generator? I want to try to set up a 2 > > stage boost controller that is triggered by a certain speed off of the > > sensor. > > Anybody out there have any info to share? > > > > LMK > > Sean > > > > -----------------------REMOVE-FOOTER-WHEN-REPLYING---------------------------- > > Questions? Visit http://www.sdml.org/ > > > > To be removed, visit http://www.sdml.org/pages/leave.html > > -----------------------REMOVE-FOOTER-WHEN-REPLYING---------------------------- > Questions? Visit http://www.sdml.org/ > > To be removed, visit http://www.sdml.org/pages/leave.html -----------------------REMOVE-FOOTER-WHEN-REPLYING---------------------------- Questions? Visit http://www.sdml.org/ To be removed, visit http://www.sdml.org/pages/leave.html
