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Forum nameEngine Management Systems & Controllers
Topic subjectPWM 2 Stepper Feeler
Topic URLhttp://forums.2gnt.com/dcboard.php?az=show_topic&forum=54&topic_id=3815
3815, PWM 2 Stepper Feeler
Posted by Ready4Dis, Dec-31-69 05:00 PM
Well, I am going to be putting in a megasquirt 1 v2.2 into a buddies 98 eclipse, and we were talking about idle control. I am considering making him a PWM 2 Stepper motor controller board that takes the PWM signal in, and connects to his stock stepper motor and an input for Load (a/c line to allow it to compensate for heavy loads). I was wondering if there was any market for such a device, since a one off PCB is going to cost more than it'd be to convert to a PWM IAC. Let me know you're opinions, the currect PCB design uses SMT components and measures in at .9" x .85", still not 100% sure how I want to mount it (thinking internal to the MS casing). Our other option is to just set his throttle stop and call it a day, but that seems pretty bad for a daily driver (especially with large temperature changes, and using of the A/C, etc), I could see his idle fluctuating more than just a little.

Give me your optinions on what you think about it, and how much you think it'd be worth if at all for other 2GNT'rs or even others that have steppers rather than PWM's (it will be able to drive both unipolar and bipolar steppers).
3820, RE: PWM 2 Stepper Feeler
Posted by Star Turbo Talon, Dec-31-69 05:00 PM
Contact Paul, VelociaPaola. His company was working on something like this and prototypes are expected to be available soon for testing.

I dont know how much its going to be worth since a fast idle valve works great for warmup. idle itself is just tuning.
3822, RE: PWM 2 Stepper Feeler
Posted by Ready4Dis, Dec-31-69 05:00 PM
Thanks for the heads up/info, I will have to check it out, any clue how much we can expect, and if it's mounted external or internal to the megasquirt? I may just order the parts non surface mounted and make a prototype board for use in his car, won't cost to much that way, but not as compact in size. I will let everyone know how it goes if I decide to go through with it either way. So far I have it with 4 inputs, 4 outputs (+12v, gnd, PWM signal, Load), I don't see why I couldn't mount it inside the megasquirt case, from what I've been researching I am looking at about .5 amps of current draw, so hopefully it can just use the fused megasquirt 12v line without a problem. I realize a PWM Valve works fine, but it would be much simpler to just keep his stock stepper motor, although he is not against fitting a PWM valve at this point, just trying to see if it'd be worth the effort or if people would be interested in something like that.
3843, RE: PWM 2 Stepper Feeler
Posted by Ready4Dis, Dec-31-69 05:00 PM
Well, it doesn't seem like to much interest, we will probably just set it manually for now, do a one off on a prototype board after it's all working, and keep the stock stepper, just to keep things simple. If anybody is interested later on, let me know, if there is enough interest, it wouldn't be hard to make more than 1 after the first is done, although I would prefer getting circuit boards printed for higher quality and using surface mounted chips to keep it small. I am thinking somewhere around $15 a piece would cover costs and keep it reasonable for people, that won't be much more than buying a fast idle valve, and save a bit of work trying to mount said fast idle.
3844, RE: PWM 2 Stepper Feeler
Posted by Star Turbo Talon, Dec-31-69 05:00 PM
The fast idle i have takes 3 minutes to install....one screw and 2 hoses!
3847, RE: PWM 2 Stepper Feeler
Posted by djtrickee, Dec-31-69 05:00 PM
Originally posted by Star Turbo Talon
The fast idle i have takes 3 minutes to install....one screw and 2 hoses!


Which fast idle are you using Terry? I am sick of playing with the set screw on my TB.
3849, RE: PWM 2 Stepper Feeler
Posted by Ready4Dis, Dec-31-69 05:00 PM
I didn't realize it was that easy. What about blocking off your old opening for the stepper? How much was the fast idle valve that you got. I am just trying to do some research to see if it will save anybody time or money. If not, I'll probably still do it since I wrote most of the code already, and it won't cost me to much to make a prototype board (probably about $5 since I have most of the components handy). Thanks for the info, so far it doesn't sound worth the effort to get circuit boards printed up, although for people like djtrickee, who are constantly adjusting their tb stop, a $15-$20 piece to control their stock idle motor might be a viable choice, although I have no clue how the wiring will be yet until I get it done, so it may take longer or be more difficult than just popping the fast idle valve in as you have done. I am still willing to find out though :).
5841, RE: PWM 2 Stepper Feeler
Posted by Berney97rs, Dec-31-69 05:00 PM
Originally posted by Star Turbo Talon
The fast idle i have takes 3 minutes to install....one screw and 2 hoses!


Realize this is quite an old thread, but I was just curious about what fast idle valve you are/were running. Sounds like what I need for setup.
5843, RE: PWM 2 Stepper Feeler
Posted by Tired2, Dec-31-69 05:00 PM
Why not just use the MS with the stepper motor IAC? Mine is working great with closed loop idle control. It cost me $0 more than the MS2 unit I was already purchasing.
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