Tachometer

[sam2019]

Cant think of anything else

its called quality. but what to expect from something that is sold for 6 bucks, and probably made for 1 or 2.

 

[Dool]

I think it is more complicated than that, either way I don't really need a tacho.
But I don't like it not working

 

[Dool]

The signal includes both ac and dc, not sure if this is a problem .

 

[sam2019]

what kind of sensor are you using? Hall effect should not have any AC component whereas magnetic induction naturally is AC.

 

[Dool]

The sensor/signal is the coil wire.
Disconnected the PT4 and

 

[Dool]

I tried a couple of things, bridge rectifier and a Voltage regulator didn't work and then a Diode to regulator and that was getting too hot but did drop the ac to 16V and the dc to 6V.
May try with higher wattage components tomorrow I did chose the smallest and cheapest, less than US $2

 

[sam2019]

coil wire.

induction then

 

[Dool]

I can try that but that method may not suit this type of gauge, induction would off then on and direct to the coil power would be on then off and the voltage would not be the same unless I get the right number of turns

 

[sam2019]

I missunderstaood. I thought you wind a wire around the coil wire to the spark plug which would by induction measure the number of impulses. if the coil does shoot twice during one cycle there is usually a switch to suppress one.

 

[Dool]

Signal has a Diode in line and still there is ACV.

 

[Dool]

Two different styles, one is actually connected to the coil and then the induction where wire is wrapped around the high tension lead.

 

[Dool]

 

[sam2019]

The design is OK, the plan too. seems only the execution is lacking. Back to the money argument. I wonder every day how my simple cheap oil thermometer makes it since years at a similar base price your tacho required.