BS2 pwm

Tobias

·I have a 379 peterbilt truck, the speed sensor on the truck is supposedly sending·333 pulses per second at 20 mph, ·is that enough pulses for the BS2 to recognize and debug the signal, if not do you have a solution?
Many thanks to the input.
-Tobias

Steve Joblin

what is the voltatge of the pulses?

Tobias

·I don't know when·I put a voltmeter to the sencor it has no voltage at all, it is a magneto sencor. On the back of a truck gauge where these two wires go into the gauge the one wire is marked 'signal' and they other 'signal grd'. The truck voltage is 12v if that matters.
-Tobias

Vitor

I'm working on a similar project.
The wheel sensor is a magnet with a coil around the magnet. It generates a sine wave by a reluctor on the axle that has 48 teeth.
At low speeds @5 MPH the voltage is @ 2V p-p and it increases to @ 5V p-p at @ 10 MPH after 10 MPH the frequency changes and the voltage remains constant.
The systems seems to be similar to the Peterbilt.
I have the same question as Tobias.

Martin Hebel

The BASIC Stamp has a very narrow transition voltage around 1.6V what is considered LOW and HIGH. The sine wave may be fluctuating due to noise enough to trigger multiple counts at the transistion level. You might want to put the signal though a schmidt trigger buffer or inverter to wave shape to a square wave with input hysteresis. This will provide a cleaner signal for counting.

-Martin

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Martin Hebel
StampPlot - Graphical Data Acquisition and Control
AppBee -·2.4GHz Wireless Adapters & transceivers·for the BASIC Stamp & Other controllers·

Tobias

I am using a amplifying circuit to give the BS2 a signal fo low and high, that works good but at ten miles per hour it sees pretty big numbers of 500 or 360 which 300 is well over 30 mph.

-Tobias