Tacho meter output

[jwasys]

Dear forum members,

We are working with the Magic Pie to power a small vehicle. We are wondering if there is a way to get tacho pulses from the wheel electronics so our speed indication becomes more accurate.

Regards, Arian

[Leslie]

Hi andto GM forums.

You could buy a common bicycle speedometer and use the magnet and sensor they come with and set it up as per usual.  The signal from the sensor output may suit you needs for your tacho. And this could save you from having to open up the Magic Pie housing.

[jwasys]

Hello Leslie,

Thank you for your reply.

We are considering to build multiple vehicles, so it would take extra work to fit wheel sensors. Furthermore external wheel sensors are too fragile for our purpose.

From EMI measurements, we noticed a burst for EMI synchronous with wheel rotation. This leads us to think that wheel position is known inside the contoller of the wheel. My question is, can this signal be fed out to the output wires in some way ?

Regards,

Arian van Dorsten.

[Leslie]

Hello Leslie,

Thank you for your reply.

We are considering to build multiple vehicles, so it would take extra work to fit wheel sensors. Furthermore external wheel sensors are too fragile for our purpose.

From EMI measurements, we noticed a burst for EMI synchronous with wheel rotation. This leads us to think that wheel position is known inside the contoller of the wheel. My question is, can this signal be fed out to the output wires in some way ?

Regards,



Arian van Dorsten.

Is the controller internal or external?

There is a yellow wire with the harness that can be used for other things. Connect it to a hall output maybe?

Is there a way you can use this EMI?  You obviously are getting data from the emi.  Is it accurate or is it just the phase wires letting off EMF.

I don't know what you are using and will it be good for hall signals of a motor that has 56 poles/2 ?  Is it programmable to count a hall signal per minute and divide it by 28 pulses.

So if you have  (280 pulses/pm)/28 pulses per rotation you have 10 rpm.  EMF would be 84 half AC phase.  Ultra fast signal diode could rectify a single pulse from EMF.

 I think I got this right.

[Leslie]

http://www.xs4all.nl/~jwasys/products.shtml

Interesting web presence you have there.

Maybe we should be asking you how to do this.

Do you have something that does PC sinusoidal GUI.  I "think" I can build the amplifiers.  I would like to try,  Maybe for PC oscilloscope?.

[jwasys]

Hello Leslie,

Yes I have a background in EE and do quite a bit of consulting. But there's no reason to brag about that.

But I don't understand your question very well. What is your objective ?

Arian

[Leslie]

Hello Leslie,

Yes I have a background in EE and do quite a bit of consulting. But there's no reason to brag about that.

But I don't understand your question very well. What is your objective ?

Arian

You have pulse detection and it drawing on PC software via parallel port through that 74hc549 IC.  I tcant do curves (sine)? Like an oscilloscope?  If it could be easy to do,  make a oscilloscope for PC.

I do not uinderstand everything but want to learn much more.

For your use

Hall signals on the input maybe too high voltage, so a small ohm resistor can protect the circuits a little and TVS + resistor and inductor capacitor to work for transient EMF .  How to omit the 27 pulse for a single pulse per rotation could you explain?

[jwasys]

Hello,

We will use a NE555 to convert the pulsetrain to an analog signal to drive a speed gauge.

Regarding digitrace, it's not suited for analog input, only digital. You need an ADC to convert analog signals in order to capture them by a PC. This is possible. Look for sound card based oscilloscope programs, if you haven't already.

Cheers

[Leslie]

Hello,

We will use a NE555 to convert the pulsetrain to an analog signal to drive a speed gauge.

Regarding digitrace, it's not suited for analog input, only digital. You need an ADC to convert analog signals in order to capture them by a PC. This is possible. Look for sound card based oscilloscope programs, if you haven't already.

Cheers

Ahh I play with 555 timers  Fun stuff.

I figured the digitrace was digital but this is what Id like to try out myself for learning experience with ADC. But allas the sound card works.

Thanks for the tip.

BTW did that help you with the yellow wire to the pie and the pole count?

[MonkeyMagic]

We will use a NE555 to convert the pulsetrain to an analog signal to drive a speed gauge.

Hey jwasys

Any chance you could post a schematic or a diagram pic for the 555 - to - analogue signal?

I would find this very helpful.

Cheers