Hey all, Just looking into how the afm works and was wondering... The Selin kit essentially takes both voltages from both afm's and averages them out to essentially send half the voltage from each afm to the ecu. (Making the total voltage equivalent to a single afm) Now my question is why couldnt you just make a voltage divider? If the divider you made halved the voltage at 10v to 5v, would it still halve the voltage from 8v to 4v, 6v to 3v etc? I'm assuming its not that easy but if someone with some more electronics experience could enlighten me, it would be awesome. Any and all feedback welcome!
Selin Translator has two settings..... ADD and AVERAGE. ADD is for use with Standard ECU & AVERAGE is for use with "duals modified" ECU's. The device has to be able to add the AFM voltages, as well as divide the total by 2.
I used an OP AMP to buid the circuit that combines two AFM's in an averaging configuration that way the AFM's will not interfere with each other. It would be just as easy to build an adding circuit that combines the two AFM's. The averaging is better for very high powered cars that way the voltage will not saturate the computer. Mine has ran without fault for a couple years now. There is a picture of the circuit here link<a href=http://http:www.aus300zx.com/forum/showthread.php?t=276372>link</a> . I added in a capacitor on the voltage supply and the output after this picture was taken.
Yup, aware of this, but generally most Selin users would use the divide feature as they would have their car tuned I would assume.
The basics of what you're saying is correct. The Selin is not a super computer. In its simplest form I see it like this: ...wrapped in pretty black plastic with all necessary cables + plugs hanging off it. Also both resistors need to be the same value to halve the result. I think I'd cry if I learned how much they make them for (wouldn't be much). When you flick between ADD & AVG you're changing where you pull from the circuit. The only thing you'd need to work out on the MAF is which pin is what, which I don't have a clue. Never cared to look into it. Why you suddenly so curious about it? I thought you ordered one already lol. MoulaZX
Yeah I figured as much. I'm assuming the Selin has a chip of some sort to make it a little more fancy but theres bugger all to it I'd assume. Was thinking if there is too much of a delay, I'd just cancel it and try making one.
Sorry... but that will not work. That is close but I think it is important to get this right. The AFM's run from 12V and both must be connected to negative and +12V. Therefore the signal out is also referenced to earth or negative and cannot be added in series. Have a look at this site to see how to connect the signals when the earth is common. http://www.opamp-electronics.com/tutorials/averager_and_summer_circuits_3_08_08.htm Averaging can be done with resistors: Adding is done with an OP amp: (with two signals such as AFM's you would create a gain of two by using the same resistors eg both 2k).
I never said my diagram was exactly how it was done, lol. It is quite a bit more involved, but I didn't see the need to explain it further... wasn't sure how serious Chilledpain was about it. @ Chilledpain, did you get any word yet from Z1? Mine is supposed to arrive by the end of the week. MoulaZX
After seeing Bolts' circuit in person, I don't see how anyone would want to pay $200+ for 10 bucks worth of circuitry wrapped in a bit of fancy plastic with a 'selin' logo. The componentry in those devices is pretty low-tech... just another instance of people building cars from shopping lists with no regard for what is actually best for their build
Yeah bugs the shit outta me too... I wouldnt mind paying $100. But $279rrp? Thats a little steep... Keen as to get these goin tho... I'll keep everyone updated as to the progress.
