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Re: festy's Alfa Romeo Alfetta GTV
Posted: Tue Oct 21, 2014 11:13 am
by UCMatt
Hi Festy,
I am keen to give one of your boards a go - I have an immediate application.
I don't need it packaged.
Cheers,
Matt
Re: festy's Alfa Romeo Alfetta GTV
Posted: Wed Oct 22, 2014 7:39 am
by festy
I've been playing with scaling the VSS signal up and down, results are looking promising:
(blue = VSS in, yellow = scaled signal out)
PPK reduction (division):
- 2:1 ratio
- 2d.jpg (55.31 KiB) Viewed 4015 times
- 4:1 ratio
- 4d.jpg (55.83 KiB) Viewed 4015 times
- 10:1 ratio
- 10d.jpg (54.72 KiB) Viewed 4015 times
PPK increase (multiply):
- 1:14 ratio, trying an odd ratio
- 14x.jpg (54.76 KiB) Viewed 4015 times
- 1:20 ratio
- 20x.jpg (55.3 KiB) Viewed 4015 times
I'm hitting a few issues with both measuring and generating really low speed pulses, but I think I should be able to sort that out...
Re: festy's Alfa Romeo Alfetta GTV
Posted: Wed Oct 22, 2014 9:40 am
by Holden202T
yeah i too would buy a basic board and i don't need a box or anything
Re: festy's Alfa Romeo Alfetta GTV
Posted: Wed Oct 22, 2014 4:15 pm
by festy
This might not look too significant, but...
The blue trace is a square wave, like a hall effect sensor would produce, and the yellow trace is the square wave output from my reluctor amp board.
This signal is being converted from a hall effect to a reluctor type, then back to a hall effect, eg. a universal converter
.
The "reluctor" waveform in between the conversion stages doesn't look much like a sine wave, but it's triggering the zero crossing detector pretty well as shown by the input and output signals staying 180* out of phase.
- thereandbackagain.jpg (49.76 KiB) Viewed 3985 times
Re: festy's Alfa Romeo Alfetta GTV
Posted: Sat Dec 27, 2014 2:27 pm
by festy
So I've been working on this in my spare time, and finally got around to installing it in my poor old Patrol yesterday. It's speedo has always read about 10km/h fast, so a perfect test candidate
My speedo corrector can take either a hall effect or VR (reluctor) sensor as input and can emulate both types, so will work with either as well as convert signals from one sensor type to the other.
The "correction" amount is done via a pair of trimpots - one for coarse adjustments and one for fine tuning.
There's 2 adjustment ranges - roughly 3:1-1:3, and 10:1-1:10.
My Patrol uses a VR type VSS, and now reads only about 1km/h fast at 80 so I'm pretty happy with that result
- speedo_corrector.jpg (182.46 KiB) Viewed 3883 times
Re: festy's Alfa Romeo Alfetta GTV
Posted: Sat Dec 27, 2014 4:56 pm
by VL400
Nice work, the board has turned out well!
Re: festy's Alfa Romeo Alfetta GTV
Posted: Sat Dec 27, 2014 7:02 pm
by HQ355
Hi Festy will you still be making these available for sale ? I'm still interested
Re: festy's Alfa Romeo Alfetta GTV
Posted: Sun Dec 28, 2014 9:10 am
by Holden202T
yeah nice work!
1km is good enough, and a hell of a lot better than the 10 you had before!
Re: festy's Alfa Romeo Alfetta GTV
Posted: Sun Dec 28, 2014 10:08 am
by antus
I agree, that has turned out well
Re: festy's Alfa Romeo Alfetta GTV
Posted: Mon Dec 29, 2014 12:01 pm
by festy
VL400 wrote:Nice work, the board has turned out well!
Haha thanks, but I don't think I should give up my day job any time soon though
HQ355 wrote:Hi Festy will you still be making these available for sale ? I'm still interested
I still need to do some more testing first, I'll PM you as soon as I'm done.
Holden202T wrote:1km is good enough, and a hell of a lot better than the 10 you had before!
Being "only" 10km/h out already made it one of the most accurate speedos I've ever had
I really didn't want it any closer, and certainly didn't want it reading slow at all...