Engine Speed (rpm) Sensor

[Mr2Mike]

227bhp said:

Don't be so nosey

Sometimes when you pose a question you can be intelligent enough to know that any more information is not needed and would derail the topic from the specific point needed, or it could be that you don't want the whole World to know all of your private or personal business.

And very often getting a better view of the problem may allow people to come up with better ideas on solving it.

[blank]

stevieturbo said:

Except that it very much matters.

Is it just something to view, log, what type of signal, self powered, etc etc etc ?

It is to log alongside various other signals. TTL or analogue signal would be ideal (I said this further up).

Power doesn't really matter either way.

[GreenV8S]

Are you bothered by how accurate or consistent it is? Even driving a 3rd party tacho off a coil LT can be problematic and need some playing around to get a consistent reading. Other options based on detecting an engine frequency out of voltage ripple, vibration and engine noise seem likely to be much, much harder. Compared to all that, a self contained optical tacho triggering off a dab of paint on a pulley seems a lot more promising. But it does depend on what your constraints are - how much you're willing to spend on hardware and development costs, how long you're prepared to spend setting it up on a given vehicle, how reliable you need it to be etc.

[stevieturbo]

Again, any conventional EFI system shouldnt be a problem to get a signal without any gear.

Diesel...yes more awkward.

A quick google shows this...depends how easy the alternator is to access. But this sort of device could be used somehow

https://www.youtube.com/watch?v=HhLPAPZxNsM

Probably not cheap

http://www.tinytachuk.com/HHnew.php

https://www.amazon.com/FARIA-INSTRUMENTS-Diesel-Ta...

This one a little interesting....more how they get a trigger.

http://www.ebay.co.uk/itm/Searon-Digital-Gasoline-...

They're simply attaching a small magnet to a rotating part and that generates the trigger for the hall sensor. Potentially you could do the same on most cars front pulley if it was a strong enough magnet not to go flying lol