Inductive Sensor

[Marco Santos]

Hi people.

How can i build or use a inductive sensor so i can read the RPM form
kart engine 2t 100cm3. Can anyone teach me how this sensor works? Can i
make one, with a coil on spark cable?

This are the links from the market sensors :

https://www.pixpress.com/e-store/kartparts.asp

http://www.astratech.co.uk/products/sensors/sensors.htm


http://www.bmikarts.com/shop/index.php?keywords=digatron&match_criteria=all&
shop=1

Thanks for your time.

Best regards.

Marco A. Santos

 

[dalai lamah]

Marco Santos wrote:

How can i build or use a inductive sensor so i can read the RPM form
kart engine 2t 100cm3. Can anyone teach me how this sensor works? Can i
make one, with a coil on spark cable?

First of all, if you can pick up the RPM signal from the ignition coil
primary or from a phonic wheel on the crank shaft, this is the preferred
way: you will get a far cleaner signal.

If you must pick up the signal from the spark cable, you can do it - and
most of these sensors do it, even the PI - by capacitive coupling: put a
wire near to the spark cable (no need to make a lot of windings), then
input the signal to a monostable with an high impedance input (for
example a CMOS version of a 555). You will get a signal with duty cycle
proportional to the RPM. Then you can filter it to get a proportional
voltage and there you go.

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- asd -