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Video of a Square Wave (Hall Effect) Tachometer in DAQ Factory


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6 replies to this topic

#1 jhenise

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Posted 20 June 2013 - 12:03 PM

Here is a quick video of a hall effect tachometer that i am developing as part of a motorcycle engine analysis computer...
enjoy!



#2 pmcintosh

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Posted 20 June 2013 - 10:05 PM

cool! What hall effect sensor are you using?

My project is stalled at the moment - I went on a big learning curve discovering that reed switches are no good and have only just tested my own hall effect

Wheel Speed Sensor

If you don't know about it already I have all the code on github under SCII Vespa Labs

When I get a few other projects out of the way I'll get back into this, happy to collaborate.

#3 jhenise

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Posted 15 July 2013 - 11:17 PM

I ordered this type that senses ferrous metal targets:

 

http://www.digikey.c...5505-00-02-A-ND

 

I think i will be using the square wave tach outout from my CDI box to read RPM on a certain bike,

It puts out a 300 V square wave, need to figure out how to step it down to 10 V !??

 

I have been doing EGT and CHT with thermocouples too!



#4 LabJack Support

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Posted 16 July 2013 - 10:51 AM

The sensor you linked seems to give a conditioned 3-5V signal, if supplied with 5 volts.  If you have some other signal that gives 300V, be careful for sure.



#5 jhenise

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Posted 14 August 2013 - 03:03 PM

I started using this sensor on the motorcycle for crankshaft and wheel RPM (it detects the proximity of bolts, gear teeth, and ferrous metals as they spin around)

 

http://www.digikey.c...5505-00-02-A-ND

 

you supply +5V from the VS of the lab jack and it gives a digital 5V on/off square wave as it senses metals.

 

PROBLEM: I get a ton of electrical interference from the bikes ignition and the readings are all over the place.

I haven't looked at the signal with a O-scope yet to see what the interference looks like but the noise results in the detection of too many rising edges with the timer and readings all over the place.

 

I am running thermocouples, humidity sensors, barometric pressure sensors, and silicone temp sensors on the same lab jack with no problem. these hall effect sensors pick up a ton on interference.

 

could it be the long VS wires running down to the sensors close(ish) to spark plug wires?

the sensors them selves?

 

would a magnetic switch be cleaner then these internally magnetically biased sensors?



#6 LabJack Support

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Posted 15 August 2013 - 08:40 AM

For troubleshooting I think it would be useful to look at some things with the scope.  Look at the signal with and without the ignition going, if that is possible.  Look at VS with and without the ignition going to see if you see anything there.

 

As for using a different type of sensor, we don't have the experience with your exact application to say if other types would be better or worse.  Also at this point, we don't know if the problem is the actual sensing part of the sensor, or if VS is getting messed up, or if the signal output from the sensor is what is affected.



#7 drail24

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Posted 12 March 2014 - 12:37 PM

Nice work jhenise.  I just purchased a labjack unit and I am trying to do something very similar, but I want to use an existing toothed crank trigger wheel and a Hall effect or VR sensor instead of capturing the actual signal out of the ignition.. as I want to eventually be able to break the data down into degrees of crank rotation per unit of time.

 

Are you able to record and playback the data or are you just monitoring the raw data through the DAQFactory software?  

 

Thanks




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