speed sensor, how do they work?
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Posting Guru
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From: MI
speed sensor, how do they work?
Im putting an 05 10.5" under my 91. It has a speedo gear driven speedo. Long story short the speedo gear got stripped and I got no speedo.
If i purchase an electric speedo, can i simply hook it up and feed it the signal from stock speed sensor?
Never dealt with electronic speedos before.
If i purchase an electric speedo, can i simply hook it up and feed it the signal from stock speed sensor?
Never dealt with electronic speedos before.
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Posting Guru
Joined: Mar 2012
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From: MI
What i mean is, can i use the speed sensor that is inthw rear end, and relay that signal to an aftermarket electronic speedometer? i believ the sensor in the rear end housing is a hall effect as there is a tone ring rotating below it.
Post Fiend
Joined: Mar 2009
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From: Mt. Shasta California
I don't know but I doubt it and maybe some more knowledgeable will chime in. They didn't have tone rings etc when I was working on cars. That ring is the only major change on rear ends in at least 40 years.
Post Fiend
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From: Mt. Shasta California
We know that.
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Fleet Owner
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From: Spanaway
The signal from the sensor needs an intermediate device to
convert it so that the display can show it on an analog type
dial. Also in the case of the newer clusters they are all digital
and have something like a stepper motor that can be commanded to
a given degree position. If you already have a cable drive speedometer
it would be less work to repair that and not to convert it.
As the speed of travel goes up the pulse will narrow and increase
in frequency. The PCM takes this and turns in into digital that is
passed to the cluster and the cluster controls the position of the
needle of the indicator in relation to the speed.
Sean
convert it so that the display can show it on an analog type
dial. Also in the case of the newer clusters they are all digital
and have something like a stepper motor that can be commanded to
a given degree position. If you already have a cable drive speedometer
it would be less work to repair that and not to convert it.
As the speed of travel goes up the pulse will narrow and increase
in frequency. The PCM takes this and turns in into digital that is
passed to the cluster and the cluster controls the position of the
needle of the indicator in relation to the speed.
Sean
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Cargo Master
Joined: Jun 2008
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From: Stillwater, OK
yep. The processor translates the frequency of the tone ring (Hz) into a speed (MPH) then provides an output (pwm) that corresponds with the correct angle on the needle.
The processor could be bypassed where the tone ring is the PWM signal, but you would have to design an excitation board to power both sensor and actuator as well as a signal modifier to make the hall effect sensor output become the servo input.
The old gear and cable use eddy currents and calibrated spring... nothing swaps over.
The processor could be bypassed where the tone ring is the PWM signal, but you would have to design an excitation board to power both sensor and actuator as well as a signal modifier to make the hall effect sensor output become the servo input.
The old gear and cable use eddy currents and calibrated spring... nothing swaps over.
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