Speedo out to drive DC motor
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- Posts: 1696
- Joined: Fri Apr 04, 2008 1:28 pm
Re: Speedo out to drive DC motor
Here's some code to test:
It fixes at least one issue (a conflict on the pin setting when bit-banging the outputs), and makes the PWM on/off behavior appropriate when using the 'always on' set-up. I'm not sure it will fix the 'drop out during shifting' issue - let me know if it doesn't.
Eventually the fixes in this code will be incorporated into 2.203 release code, once this is fully sorted to everyone's satisfaction.
Lance.
Re: Speedo out to drive DC motor
We have a winner!!
This sorted all issues.....
PWM percent is now responding exactly as it should (Ok just tested SP1)
Now I also get correct responce when changing PWM period.
I do not loose the signal anymore while shifting gear.
I'm very thrilled with the resulst and I can also confirm that it is possible to use a small DC motor to run your old mechanical speedo... got stuck there for a while testing different PWM periods to get most torque on lower speeds and by using the table speed/PWM% I manage to get the speedo spot on compared to the speedo in TS.
Many thanks Lance for your pation with me.
I can post some more scope screens if you want to see the result on my board
BR//Tobmag
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- Posts: 1696
- Joined: Fri Apr 04, 2008 1:28 pm
Re: Speedo out to drive DC motor
Tobmag,Many thanks Lance for your patience with me.
I am thrilled it's working now! And all my thanks to YOU for your patience with me. It really helps when people keep pushing when something doesn't work - just because I don't see a particular problem doesn't mean it's not there, as you have shown. Often this is due to different test methods, set-ups, etc.. Your persistence and commitment are exactly what's needed to make the code better.
I can see that it's better on my scope too, but if you put up a scope shot or two for people stumbling on this thread later, that would be helpful.
Lance.
Re: Speedo out to drive DC motor
I'll post some scope screens tomorrow, now its way past my bedtime
BR//Tobmag
Re: Speedo out to drive DC motor
Please note that PWM% seen in TS and Duty cycle seen in my scope screen are inverted!!
BR//Tobmag
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- pwm10%.png (8.47 KiB) Viewed 12278 times
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- pwm50%.png (8.83 KiB) Viewed 12278 times
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- pwm95%.png (8.32 KiB) Viewed 12278 times
Re: Speedo out to drive DC motor
I've been off here for a few weeks while I built a couple engines, a Chevy 12 bolt posi rear and an M-22Z muncie conversion.
I trashed my GPIO while sanding off the end to get it in the case. Fried a couple components, lifted a pad, etc, etc. same old sad story. But now my wife (experienced in SMT build and repair on cruise missile guidance/control boards) has agreed to help me fix it. It won't be long.
Will you be willing to disclose what electric motor and associated parts you used? maybe schematics? My mechanical skills are excellent but my electronic skills are very limited.
Re: Speedo out to drive DC motor
I'm using an 12v DC motor coming from an old VCR I srapped a few years ago.
Have a look what the R/C peolpe use, there are a huge amount of different motors availible.
Wiring , nothing odd just add the diod over the motor to kill the spikes.
BR//Tobmag