Rpm Counting

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TKS said:
ok nigel,

i will go out and buy an osciloscope or have you got anny better idea???

i could just buy another sensor right? but the oscilioscope will be more usefull right??
Click to expand...

An oscilloscope is ALWAYS useful, but they are quite expensive. Don't you know someone who has one?, or even a local school?, where you could take your sensor and test?. For that matter how about a local TV engineer?, we are easily bribed to help :lol:
 
mhh

the problem is nigel that to be ablte to test the sensor setup i will need to
showup the complete hub right??

Its the only way to hve everything like in reality,

i like electronics, sow if you help me with advice i will buy an osc.

Or what we also could do is if you can tell me your location maybe some one else (in the UK) wants to go to you with the same setup as me that is also possible......

Tks
 
Re: mhh

TKS said:
Or what we also could do is if you can tell me your location maybe some one else (in the UK) wants to go to you with the same setup as me that is also possible......
Click to expand...

My location is already in my profile, which is as accurate as is needed, I'm actually about 5 miles west from junction 29 of the M1 motorway.
 


Will try to find someone....

else what are the minimum specs of the Osc wich i will need to buy???

Regards,

Tks

i have seen on the net some scopes wich uses the laptops lpt port

do you think its the trying worth???

TKs
 
Re:

TKS said:
Will try to find someone....

else what are the minimum specs of the Osc wich i will need to buy???
Click to expand...

Any scope is far better than none, but a 20MHz double beam scope is suitable for almost anything you will ever need - and anything more than that is an added bonus.

i have seen on the net some scopes wich uses the laptops lpt port

do you think its the trying worth???
Click to expand...

They are generally low spec and expensive as well, although they do give you some facilities a real scope doesn't - but you should consider them as additional to a scope, not a replacement for one.
 
well ok

i have found a 10Mhz one can you take a look at it please??

its 10Mhz and one channel only but please look at the specs because think its reasonable priced! (150/1.52 @ 100pounds)

**broken link removed**

Regards,

Tks
 
Re: well ok

TKS said:
i have found a 10Mhz one can you take a look at it please??

its 10Mhz and one channel only but please look at the specs because think its reasonable priced! (150/1.52 @ 100pounds)

**broken link removed**
Click to expand...

It's a very low spec scope, better than nothing, but you could get a second hand scope far better for less money.
 
Nigel

I found on the net this circuit, can cou explain if it is usefull for me to use.

The biggest thing is if i need to use the special components wich are used.

The VR sensor would be connect to the left input and to ground.
 

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Re: Nigel

TKS said:
I found on the net this circuit, can cou explain if it is usefull for me to use.

The biggest thing is if i need to use the special components wich are used.

The VR sensor would be connect to the left input and to ground.
Click to expand...

I would imagine it would be useful, but again, without knowing what your sensor outputs it's just guesswork?. There doesn't appear to be anything special used in that circuit, what are you concerned about?.
 
well

The circuit you see is used in the mega squirt system.

Mega Squirt is the DIY injection system.

That system uses the VR crank wheel sensor to be able to know when the cylinder is in his upper position.

enfin,

i think that with that scheme my abs sensor should work.
Mega squirt is build to be able to accept a wide range of sensors.

also i looks like it uses the 0 passing as the signal and not the high going pulse of the sensor is this right?


any way when i look at the datasheet of the transistor it looks like a special one? i compared it with the BC547 but wy does this one have negative values?

could i use the 547?? or do i need to order this one??

still searching for a scope.

Yesterday i did some tries with my ADC scope i could get a ADC value of 170 out of the Micro controller...

but when not turning the wheel i also reached 43 sow dunno how liable it is...

Tks
 
Re: well

TKS said:
any way when i look at the datasheet of the transistor it looks like a special one? i compared it with the BC547 but wy does this one have negative values?

could i use the 547?? or do i need to order this one??
Click to expand...

There's nothing special about the circuit, a BC557 (NOT a BC547), should be fine - notice it's PNP.
 
mhhh

How much % change do you give me that with this circuit the sensor will work?? using a PNP transistor??

Looks its more complicated to untherstand isn't it?

I have also seen on the net a 4kHz pc oscilioscope do you think it could be util??

Tks

p.s. i was also thinking he... couldn't i use a max232 chip and connect the

VR sensor to the 2 RS232 level Inputs?? when the sensor would give -12

it should do something on the other side of the chip right??

or is this a bugger solution...
 
Re: mhhh

TKS said:
How much % change do you give me that with this circuit the sensor will work?? using a PNP transistor??
Click to expand...

I don't know, there's not much gain in that circuit, but the comparator looks like it switches at a fairly low level. Why don't you just use an opamp to amplify the signal from the sensor? - the snag been of course that you don't have any idea how much gain you need!.

Looks its more complicated to untherstand isn't it?

I have also seen on the net a 4kHz pc oscilioscope do you think it could be util??
Click to expand...

Doesn't look very useful to me?.

p.s. i was also thinking he... couldn't i use a max232 chip and connect the

VR sensor to the 2 RS232 level Inputs?? when the sensor would give -12

it should do something on the other side of the chip right??
Click to expand...

You've got a small, unknown signal, that's probably too small to fed directly into a 5V logic input, so why would feeding it into a 24V logic input help?.

Does no one in your country have a scope?, don't you have schools?, don't you have TV engineers? - take your sensor along and go and beg!.
 
Mhh

Nigel,

i'm liveing in a vilage/town (smallest one) sow here is no one who has a scope.

Well you give me the idea to give the sensor to my brother he is on a school wich could be able to help me.

Proberly he could help.

On the other side as i mentioned the highest value what the microcontroller gives is 170 ==> 0,83Volts...

What whould happen if i pre charge the base with lets say 0,5volts..

wouldn't the adding 0,2 from the sensor make it go in full mode...

offcourse we should filter out the voltage that comes when applying the 0,5 volts...


Will try something with crocclip...

a mosfet driver is that of anyuse??
(opamp??) anyway i will need something to be ablte to adjust the signal right??

Also we should take in consideraton that the Vr sensor might give voltages as high as 50volts!

Nigel you are a electric god...and i swear that when hooking up the sensor to the NPN with a 25K base GND resistor and Vr - to gnd Vr+ to base..and it wont trigger.. the pull down used is 4,7K.. sow you should be able to calculate how much is needed to pull it down right??

Maybe i should just drop the ******* and mount an optocoupler in.
but on the other side wy??

Regards,

Tks
 
mhh

If i would use a darlington transistor array wouldn't that be of any use??

Or some bs457/bc458 after each other shouldn't that amplyfy the signal??

isn't there a way to calculate what voltage producec a coil wich has 1000ohm initial resistance... and when you move something arround it gets to 800ohm and 1300ohm...

??

How could i make my adc scope sow it will read a usaable value??

1Mohm to ground to adc pin..?

and 1K to adc pin and as probe??

Tks
 
You can use any type of amplifier, I only suggested an opamp because it's so simple - but it still comes down to you don't know what the initial signal level is!.

BTW, I live in a small village as well, we don't even have a shop, but we do have two pubs 8)

However, within a 3 mile radius there are three secondary schools, all of which will have oscilloscopes.

Admittedly Britain is small and densely populated, but the children from your village must go to school somewhere?.
 
yes

well in fact we have many pubs but only 2500habitans??

the school we have is the lower one, after that one every one moves to Salamanca and hires their a room/flat etc.

Salamanca = 40miles away from where i live..

another option would be Bejar wich is 15minutes driveing..

but the problem is when etc..

With 3 transistors cant you give me a idea with 3 of them??

to opamp the signal..??

i want to do something this evening/night..

assume the voltage it gives is 0,25 volts..

Tks
 
Just try a single transistor amplifier, in common emitter mode, and AC couple it - you can alter the gain by bypassing the emitter resistor with a capacitor. But you don't know what's going IN, nor what's coming OUT, which means you're working blind.
 
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