tegwin
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| posted on 7/5/08 at 12:47 PM |
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DIY electronic speedo healer
From what I can see the actual theory behind a speedo healer is simply to change the pulse frequency by a variable amount to allow callibation
I can see various ways of doing this using some form of counter and trigger circuit....It is going to take me ages to figure out the best way of doing
it....
Are there any schematics that people have used in the past to solve this problem? I dont really want to spend £70 on a few quids worth of components
if I dont have to!!!
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mackei23b
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| posted on 7/5/08 at 12:53 PM |
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Speedohealer
Try one of these kits for £14.50.
I've got one and it works perfectly with ZX9r Clocks and sensor.
http://www.jaycarelectronics.co.uk/productView.asp?ID=KC5435&CATID=25&keywords=&SPECIAL=&form=CAT&ProdCodeOnly=&Keyword1=&
Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=347
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02GF74
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| posted on 7/5/08 at 12:59 PM |
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yep - that is how that one would work - no doubt using a PIC.
for £ 15 quid I don't need to say more other than I could probably make one for about a fiver but take me much longer to do
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mackei23b
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| posted on 7/5/08 at 01:38 PM |
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Yes it uses a pre programmed PIC.
I came to the same conclusion, yes I could design the circuit and wright up the programme, but it will take some time to save only £10.
That said I still fancy a doing a digi dash using a PIC, but that may be the next project once the car is registered and on the road.
Cheers
Ian
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badding
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| posted on 7/5/08 at 01:38 PM |
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I'm not using a speedo healer on my indy, it's pretty close without one..using the original bike clocks.
30 mph on the clocks were 26 on the tom tom. Speed sensor is mounted above the propshaft..speedo was however marked as k/mh
Just put a little black tape over the "k" now is says m/h which is ok for sva.
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matt_claydon
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| posted on 7/5/08 at 02:17 PM |
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Does anyone know if you could use/adapt this for a rev counter? I've got a 4-cyl tacho and am putting in a 5-cyl engine so need to do something
to the signal to make it read correctly. I'm guessing the signals are not quite the same, but maybe with a couple of extra components?
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mackei23b
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| posted on 7/5/08 at 02:34 PM |
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Yes it could potentialy work for that by reducing the frequency by 20%
Cheers
Ian
quote:
Originally posted by matt_claydon
Does anyone know if you could use/adapt this for a rev counter? I've got a 4-cyl tacho and am putting in a 5-cyl engine so need to do something
to the signal to make it read correctly. I'm guessing the signals are not quite the same, but maybe with a couple of extra components?
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02GF74
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| posted on 7/5/08 at 02:37 PM |
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^^^ yes you are correct in all of your assumptions.
I am sure it can be adapted to work with rev counter. These work differently to electornic speedo whcih have pulse counting electronics to control a
stepper motor for the pointer. Tacho's make use of a charge pump and have in effect a voltmeter. some of these have a 3 way switch to allow
selection between 4-6-8 cylinders which is not what you want.
What the switch does internally is to switch in different value of reisstor.
Now if you were able to get inside the tachometer, it may be possible to figure out the electronics and fit in a different value of resistor - 17p vs
£ 15 or more quid.
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BenB
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| posted on 7/5/08 at 03:19 PM |
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quote:
Originally posted by mackei23b
Yes it uses a pre programmed PIC.
I came to the same conclusion, yes I could design the circuit and wright up the programme, but it will take some time to save only £10.
That said I still fancy a doing a digi dash using a PIC, but that may be the next project once the car is registered and on the road.
Cheers
Ian
I did a digi dash a while back. Tons of source code, never did finish it properly, I think my brother bought one in the end!!!
I used a 16F84A on the "display" board which controlled the LCDs and a 16F877 oin the mainboard which did the A/D conversion and talked to
the '84.
Worked nicely..... Had blue and red (min and max) alarm trigger points which were user adjustable using buttons on the mainboard....
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mad4x4
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| posted on 7/5/08 at 06:12 PM |
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Damn Oil's a bit hot and battery voltage a bit hi there mate ....
Scot's do it better in Kilts.
MK INDY's Don't Self Centre Regardless of MK Setting !
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tegwin
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| posted on 7/5/08 at 07:12 PM |
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Not if he is running a gas turbine engine on a 25V bus
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Would the last person who leaves the country please switch off the lights and close the door!
www.verticalhorizonsmedia.tv
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matt_claydon
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| posted on 7/5/08 at 09:33 PM |
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Thanks for that. Interesting as I'd always assumed tachometers used pulse counting. This one doesn't have any external switches but will
open it up sometime and see if I can see if it could be modified internally.
Cheers,
Matt.
quote:
Originally posted by 02GF74
^^^ yes you are correct in all of your assumptions.
I am sure it can be adapted to work with rev counter. These work differently to electornic speedo whcih have pulse counting electronics to control a
stepper motor for the pointer. Tacho's make use of a charge pump and have in effect a voltmeter. some of these have a 3 way switch to allow
selection between 4-6-8 cylinders which is not what you want.
What the switch does internally is to switch in different value of reisstor.
Now if you were able to get inside the tachometer, it may be possible to figure out the electronics and fit in a different value of resistor - 17p vs
£ 15 or more quid.
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MikeRJ
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| posted on 7/5/08 at 11:27 PM |
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quote:
Originally posted by matt_claydon
Thanks for that. Interesting as I'd always assumed tachometers used pulse counting.
The lovely chronometric ones do!
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BenB
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| posted on 8/5/08 at 09:55 AM |
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quote:
Originally posted by mad4x4
Damn Oil's a bit hot and battery voltage a bit hi there mate ....
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