Hi All,
Ive got an old (restored) MK3 Ford Fiesta RS1800 in which ive changed the differential so that unfortunately the original mechanical speedo drive is no longer functioning. I do however (to keep it original looking) want to retain the original mechanical speedo. I have fitted an ABS sensor to the gearbox to supply a speed signal.
I've obtained a suitable motor with 5:1 gearbox hooked up to the speedo cable that used to go to the gearbox and when running on 12v will see the speedo exceed the maximum speed indicated.
The speedo drive has a feedback hall effect unit in-line with the original speedo cable to supply feedback pulses to keep the motor and indicated speed correct in case of friction etc in the speedo cable drive setup.
My question is: do i program the picaxe to take the speed pulse train from the ABS sensor and 'map' it to a table such that the feedback sensor feeds the correct speed pulses back according to the table and hence motor speed to display the correct speed on the mechanical speedo OR do I set a linear relationship between the speed pulses-in and the feedback pulses to display the correct speed??
Or can you think of a better, simpler or cleverer way of achieving this?!
regards
mark
Ive got an old (restored) MK3 Ford Fiesta RS1800 in which ive changed the differential so that unfortunately the original mechanical speedo drive is no longer functioning. I do however (to keep it original looking) want to retain the original mechanical speedo. I have fitted an ABS sensor to the gearbox to supply a speed signal.
I've obtained a suitable motor with 5:1 gearbox hooked up to the speedo cable that used to go to the gearbox and when running on 12v will see the speedo exceed the maximum speed indicated.
The speedo drive has a feedback hall effect unit in-line with the original speedo cable to supply feedback pulses to keep the motor and indicated speed correct in case of friction etc in the speedo cable drive setup.
My question is: do i program the picaxe to take the speed pulse train from the ABS sensor and 'map' it to a table such that the feedback sensor feeds the correct speed pulses back according to the table and hence motor speed to display the correct speed on the mechanical speedo OR do I set a linear relationship between the speed pulses-in and the feedback pulses to display the correct speed??
Or can you think of a better, simpler or cleverer way of achieving this?!
regards
mark