[Diy_efi] Stepper Motor to drive mechaical speedo

[David Allen]

I've built several PIC projects before. What sort of frequency are you 
dealing with?


----- Original Message ----- 
From: "Hugh Keir" <hugh at sol.co.uk>
To: <diy_efi at diy-efi.org>
Sent: Monday, October 22, 2012 9:15 AM
Subject: [Diy_efi] Stepper Motor to drive mechaical speedo


> My new stepper motor arrived at work today, so if it is fast enough to
> drive the speedo, I will post a youtube video showing what the set-up
> looks like.
>
> Whatever happens regarding the stepper motor / servo motor solution, I
> will need some sort of programmable output to drive the speedo.
>
> Turns out that I also need a speed input to the ECU and also to the Corsa
> ( UK ) electronic power steering system I am going to graft on to the car.
>
> It would be great if someone can show how to manipulate the pulses from
> the hall sensor with a PIC.
>
> Thanks
>
> Hugh
>
> On 10/19/2012 11:44 PM, jimster1 wrote:
>> Normally it's going to be 1000 turns\mile.  Dials out to be 60MPH as 
>> well.
>> Some British speedos are different, but are usually marked in tiny
> script on
>> the face.
>> Jim
>
> Thanks-
> I looked around a bit more last night.
>
> AutoMeter says 1000 RPM at 60 MPH.
>
> That means the drive motor - stepper or DC - needs to run 2000 RPM for
> 120 MPH,etc.
> Seems like a 500 RPM stepper will probably not do the job.
>
> comment- Driving a DC motor - instead of doing PWM on a fixed frequency,
> do it the other way-
> Deliver a fixed pulse width on variable freq- like (for example) the
> pulse train that you get fromm the speed sensor.
> To calibrate the motor speed, adjust the pulse width.
>
> FWIW
> Jay
>
>
>> -----Original Message-----
>> From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org] On
>> Behalf Of jayjunk at laserpubs
>> Sent: Friday, October 19, 2012 9:23 PM
>> To: diy_efi at diy-efi.org
>> Subject: Re: [Diy_efi] Stepper Motor to drive mechaical speedo
>>
>> Ok - is there a standard revs/mile for a speedometer/odometer?
>> The only thing I found so far is for a Vincent motorcycle!
>> (1600 rev/mile)
>>
>> cheers...
>>
>> On 10/19/2012 5:04 PM, jayjunk at laserpubs wrote:
>>> Funny- I was going through my garage and found my stash of gauges.
>>> I found a 120 mph mechanical speedo (SW style) that will be just fine
>>> for my mutant Corvair.
>>> Now I need to look around for a DC motor with enough grunt to drive the
>>> speedo!
>>>
>>> cheers
>>> Jay
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