\\\\\Attention Electronics inventors/////

[lee]

Anybody know how to count sine waves (REALLY cheaply!)? I believe that's what the ABS brain detects from the tone wheels on the SVX. I am interested in conducting a test of front vice rear tire rotation and it would introduce rigor, reliability, and be easier too, if I could use some sort of counter. I want to wire it up as a "T" off the ABS computer wires coming from the sensors. I would prefer two absolute counters, but probably would accept something that measured the difference in the two counts.

BTW, this has to be a circuit with lots of inherent or add-on isolation, I don't want to fry my ABS computer.

thank you one and all.

[Landshark]

Originally posted by lee
Anybody know how to count sine waves (REALLY cheaply!)?

you can use your fingers and toes. in your case Lee, you can only count to 24, though..

[lee]

Originally posted by Landshark


you can use your fingers and toes. in your case Lee, you can only count to 24, though..

Hey, I resemble that remark!!! (with apology to the 3-Stooges or whomever first used that line)

[oab_au]

Originally posted by lee
Anybody know how to count sine waves (REALLY cheaply!)? I believe that's what the ABS brain detects from the tone wheels on the SVX. I am interested in conducting a test of front vice rear tire rotation and it would introduce rigor, reliability, and be easier too, if I could use some sort of counter. I want to wire it up as a "T" off the ABS computer wires coming from the sensors. I would prefer two absolute counters, but probably would accept something that measured the difference in the two counts.

BTW, this has to be a circuit with lots of inherent or add-on isolation, I don't want to fry my ABS computer.

thank you one and all.

Hi Lee, You at it again.
You can use a Smitt trigger to pick up the signal from the ABS pickups. To do the counting I would use an up down counter, loaded with a number,say 100 then the front pick up triggers the up count and the rear triggers the down count.

Use Cmos to prevent loading the pickup signal too much.

You are determand to work this out arn't you.

Harvey.
Ps do you want the chip numbers or can you find them?.

[lee]

Originally posted by oab_au


Hi Lee, You at it again.
You can use a Smitt trigger to pick up the signal from the ABS pickups. To do the counting I would use an up down counter, loaded with a number,say 100 then the front pick up triggers the up count and the rear triggers the down count.

Use Cmos to prevent loading the pickup signal too much.

You are determand to work this out arn't you.

Harvey.
Ps do you want the chip numbers or can you find them?.

Harvey, I understood your words individually, but not as a system, i.e., I know what CMOS or a trigger is, but past that I hit the wall. The same would be true if you just gave me chip numbers, I need to know how to hook them together too. I will be doing a net search for schematics, but if it's easy and you can do it off the top of your head, then I would be most grateful.

And yes, I have this compulsive obsession that strikes me from time to time and the only way to get the monkey off my back is to to pick up the knowledge it feeds on.

[oab_au]

Originally posted by lee


Harvey, I understood your words individually, but not as a system, i.e., I know what CMOS or a trigger is, but past that I hit the wall. The same would be true if you just gave me chip numbers, I need to know how to hook them together too. I will be doing a net search for schematics, but if it's easy and you can do it off the top of your head, then I would be most grateful.

And yes, I have this compulsive obsession that strikes me from time to time and the only way to get the monkey off my back is to to pick up the knowledge it feeds on.

OK mate I'll take a little time but I get back

Harvey.

[Trevor]

Greetings Lee,

A Schmitt (ÒSmittÓ ?), Trigger will serve no useful purpose in respect of counting a sign wave. You have available an ideal clean signal.

The sensor output is A. C. at a frequency of 45 cycles per wheel revolution. The voltage will increase with speed. At a road speed exceeding say 2 or 3 MPH you would exceed the usually acceptable rate for mechanical counters and will require an electronic instrument and most of these would require only a simple interface.

If a mechanical counter is acceptable this could be driven via a simple transistor amplifier and a very high impedance input should not be required. A Zener diode regulator may be called for depending on the peak voltage available but this can probably be controlled by means of a suitable shunt resistance as the current will be minimal.

The difficulty is that no open circuit output maximum figure is available and you would have to take measurements to establish this AC output voltage. There are figures in the manual but with no maximum figure. An ordinary digital multi meter will suffice together with a shunt resistor and possibly a capacitor network. If you wish to do this advise.

Your best option would be to unplug the selected sensor cable at a convenient point. This would be less damaging to the loom than trying to make parallel connections and would provide the full open circuit voltage to work with and would also isolate the ABS computer for safety.

As luck would have it I have a small mechanical counter to which I have added transistor driver for test purposes. You could have this but I think the air postage would exceed its value. Simple electric solenoid operated counters are often available at surplus electronic outlets but I note that you are in a small town. You may find something on the net. If you can find something and give me the specs on its operating solenoid as well as measure sensor output, I could design you an interfacing amplifier which you could build. Pity you are not close to an electronics hobby shop, or are you ? They could have a transistorised relay kit set which could be adapted.

If I can assist further, shout.

Best of luck with your interesting project, Trevor *< )

[lee]

Trevor,

As I tried to say to Harvey above, you seem to seriously have overestimated my knowledge/skill levels.

As a degreed physicist that officially means I can comfortably spout theoretical nonsense such as does the passage of time exist or is it a human contrivance. However, I haven't got more than a tiny drop of practical or common sense in my whole body (and I believe my wife would be willing to certify this for any doubters).

In another thread, mbtoloczko has suggested a practical scheme which will not yield the absolute accuracy, but has the distinct value that all it requires is my time - meaning the price is right.

Thanks to one and all for humoring me in my flights in and out of SVX insanity.

[Landshark]

how about this (or something similar in price/function - i found all kinds on ebay):

http://cgi.ebay.com/ws/eBayISAPI.dll...5&category=296

you may need a small DC-AC inverter to power the thing in the car. i actually have a frequency counter packed away somewhere......

[Trevor]

Although described as a frequency counter this type of instrument is usually used as a frequency indicator i.e. the read out shows cycles per second.
Functions include Gated Totalise but I do not think it has a running totalizer function as is required. However it does have the required range and input parameters. Looks like it may go very cheap but is it OK.???

In any event a depth of electronic knowledge is required to drive it. To be sure your efforts in checking ebay will be appreciated.

[Ron Mummert]

[QUOTE]Originally posted by lee
[B]Trevor,


As a degreed physicist that officially means I can comfortably spout theoretical nonsense such as does the passage of time exist or is it a human contrivance.


OK, Lee. Which is it?


Thanks, Ron (If a contrived tree falls in a forest, will it land on a theoretical tree-hugger)?

I get the feeling you'd like to do this for <$100 without having to solder... So, you'll need 2 digital meters that register frequency. High end stuff like Fluke is great but expensive. You can get a meter at radio shack for quite cheap. If you don't have a meter yet, I'd sugest getting one very good meter, I've had the same fluke for over 15 years, and one beater meter (you could leave in your car)

Anyway, disconnect the sensors, plug in the meters, set to "Hz" and read the difference.

This also has the advantage of instantainious readings. Meaning no timing, calculations, or deviations due to steering angle, road camber etc.

Happy Physics!

Collins

[lee]

[QUOTE]Originally posted by Ron Mummert
[B]

Originally posted by lee
As a degreed physicist that officially means I can comfortably spout theoretical nonsense such as does the passage of time exist or is it a human contrivance.


OK, Lee. Which is it?


Thanks, Ron (If a contrived tree falls in a forest, will it land on a theoretical tree-hugger)?

Like I have a clue.

However, I think I can help you with the tree question. The short answer is maybe.

The full answer is, of course, it depends. The dependencies are at least three-fold: 1) is it a weekend, and 2) where geographically is the forest, and 3) what kind of contrived tree it is, i.e., coniferous or deciduous.

Let me explain. On the weekends, all the real & theoretical tree huggers head for the hills & mountains in much the same fashion as the weekend Harley biker type puts on black leather and trailers his bike to someplace to be seen. However, the tree-hugger does this because they prefer contrived trees to real people. The location variable involves the dominant tree type in the location of specific interest. For example: since the deciduous tree is relatively rare compared to coniferous in the hills & mountains of CA, the theoretical tree-huggers would be clustered around a contrived deciduous tree. Therefore, regardless of which way it fell it would be sure to get one of them. The Golden State thing is actually important because of the higher density of "high" people (especially around Humbolt County). They would be so enraptured by the contrived tree falling on them, they would forget to move. Of course people in this state of mind exist almost everywhere - that's why the answer can only be answer meaningfully when contrasting tree types. Hope this helped.

[lee]

Originally posted by ww111
I get the feeling you'd like to do this for <$100 without having to solder... snip...

I don't mind soldering, I just wanted VERY cheap.

[Ron Mummert]

Originally posted by lee


The Golden State thing is actually important because of the higher density of "high" people (especially around Humbolt County). They would be so enraptured by the contrived tree falling on them, they would forget to move. Of course people in this state of mind exist almost everywhere - that's why the answer can only be answer meaningfully when contrasting tree types. Hope this helped.

Yes, Lee, it's perfectly clear. In fact I think the Golden State's problems could be solved by rounding up all the gubernatorial candidates & dropping them in Muir Woods. All will be forced (well, not exactly "forced") to imbibe upon peyote & murmur "OOOOHHHHMMMM" until an earthquake is congered, thus felling many redwoods, thus mercifilly crushing many superfluous contenders. Mercifully, only two shall emerge to be declared ballot worthy. The ballot shall read, 1. Yes, 2. No, 3. Undeciduous.
I'm sure this really makes sense.
You're welcome.

Ron (danglin' my chads).