Ok here goes. I have a set of smiths gauges out of a mgb . Mechanical drive speedo is included in it. The t5 tranny I have has both electric and mechanical out. I have a 90 deg mount for the mgb cable but its not looking like its going to fit. and I was wondering about making a board to control a stepper motor that could drive the smiths mechanical speedo. The stepper controler would be driven by the pulses from the t5's electrical out. It could also make the calibration of the old Gauge a bit easier once done -
Does it sound plausible or maybe someone makes such a thing.
Dale

autometer does

http://www.autometer.com/cat_accessorieslist.aspx?pid=28

but I think it might be for their guages

That looks like it does the oposite of what I am looking at doing. I need elctrical to mecanical.
Dale

I think it may be possible , you would need to design some sort of servo drive using digital to analog conversion and feed back from the motor to maintain accuracy.Maybe you could use a decent quality model motor and fit a couple of magnets and a hall effect sensor for the feedback.
Paul

I'm sure this is doable. Maplin do a stepper motor driver IC: L293D Stepper Motor Driver and probalby the motors too.

You need to work out how fast you want to drivethe speedo i.e. motor and pulse rate from gearbox. You will need to make some circuitry to scale the two values, either digital or analalogue.

Maplin do PIC that you can prrogram so are infinitely adjustable; only about 2 quid - but the programmer is about £20.

I have a feeling that your better bet is to stick anotrher tacho on with the speedo gauge face. The tacho is a 270degree moving coil meter & deflection is proportional to the milliamps going through it. This is clearly more suitable for speedo display but odometer would be a bit of a bugger. . . .
Oh yeah - to convert pulses to milliamps easiest way is a charge pump, 2 diodes & a capacitor, here's a circuit
Bob

I found a company that does it but there rediculous in price.
http://www.gaugeguys.com/cablex.htm

I have to go through my stuff and se if I have a stepper controler that will work. Or a voltage/current controled motor- I have lots of old steppers and printer drives ect available.
Dale