Hello, after getting my innovate LM1 A/F logger, i would like to have RPM input in it to cross information. Problem is that the innovate rpm converter costs over 100€.. I know frequency to voltage chips are very cheap, and i hate when simple things are overpriced so i dont care if it takes some time (i am not stressed with time), i would like to build my own converter.

I have seen little but some documents on internet about this subject, one of wich -> http://forums.evolutionm.net/showthread.php?t=159682

But the info got "dead" with time so i need fresh knowledge. My LM1 input is from 0 to 5 volts, so i need to build a frequency to voltage with these parameters and accurate. The software i have displays gauges in real time, so i could verify with ease if my converter is accurate or not.. (at least to get an idea)

Someon built a converter like this or can help me with this ??

Thank you in advance

 

you might want to check with pgmfi.org. they do lots of that type of stuff and im sure could help you out. ill even make it simple with a link http://forum.pgmfi.org there is a section there called "toys and tools" that you can post in for that type of info

 

thank you!!

since the time of my request i have done research and i am getting a bit closer.

found out i need a Lm2917n chip to do the conversion.. i need now a schematic of it to build the thing.

thanks! willl check the link now

 

the schematic to build the thing is right in the datasheet for the chip! i posted one a few years back, but it's an an amazingly simple circuit.

 

great, will look into that. thank you very much!!!

 

Just look for F/V converters. Frequency to Voltage.


Also, look at the datasheets as some require more external hardware to function. Look for the ones that are the simplest.

 

the main issue for me right now is to have it output with a mini ISO plug. Because the Lm1 as that very same mini ISO plug input.

basicly i need the schematics with that in mind AND also having it "talking" from 0 to 5 volts to the lm1

 

I'm not sure I understand...are you trying to build your own RPM Convertor box like the one Innovate sells already? Because if you already have the box/cable with the (5) 0-5v inputs, it has the convertor built in.

I love innovation and new things, but if you take the amount of hours it takes you to research this and multiply it by the wage you make at your current job, and the cost of parts (raw materials & shipping)...I bet its more than $99...I wouldnt say $99 is overpriced to most people that use these products, but if you are unemployed, or just are just doing it to learn, good for you

 

you are right in one thing, it will take me time and research along with learning. But i dont earn much at my job, i get myself around 450 US dollars a month so i live barely with it. the 100 dollars the rpm converter costs is a lot for me. getting the lm1 is already heavy for me to support. But i love my car and i love tuning it so i do the extra effort.

I will get it right, somehow.