Hi everyone, this is my first post... I plan to spend a lot of time here.
I need to tap into a wire in my car that is a yes/no knock signal. Basically if there is (or isnt ,im not sure) voltage, the motor is knocking. It is a signal coming after all of the filters and whatnot, it is not actually a knock sensor output. It is filtered.
I want to be able to drive a led off of this wire, so that I can monitor knock as I drive. The problem is I know nothing of the nature of the signal in the wire. The factory manuals are useless and all the car forums dont help much. I am guessing that the signal is somewhere between 0 and 5 volts, but it could be up to 12v. I would hook it up to a scope, but I do not have one, I am using the mic input on my laptop as a scope for now, with resistors of course. Plus I have to induce knock to test it, which means driving full throttle while watching my computer, that isnt fun.
My main concern are 2 things.
1. How can I tap into this signal without "disturbing" it in any way? Its main function is to tell the ecu to retard timing, so I do not want to alter it in any way. I know I need a resistor and then an amplifier, but which ones will match and how can I build them?
2. How can I make the led stay on long enough to see it? The signal may be very fast, I dont know yet. I would like some kind of time delay for the light, so it will stay on for 1 second each time it sees any voltage from the yes/no signal.
As you can probably tell, I am new to electronics, but I plan to follow this board a lot and hopefully pick things up quickly.
Thanks!
I need to tap into a wire in my car that is a yes/no knock signal. Basically if there is (or isnt ,im not sure) voltage, the motor is knocking. It is a signal coming after all of the filters and whatnot, it is not actually a knock sensor output. It is filtered.
I want to be able to drive a led off of this wire, so that I can monitor knock as I drive. The problem is I know nothing of the nature of the signal in the wire. The factory manuals are useless and all the car forums dont help much. I am guessing that the signal is somewhere between 0 and 5 volts, but it could be up to 12v. I would hook it up to a scope, but I do not have one, I am using the mic input on my laptop as a scope for now, with resistors of course. Plus I have to induce knock to test it, which means driving full throttle while watching my computer, that isnt fun.
My main concern are 2 things.
1. How can I tap into this signal without "disturbing" it in any way? Its main function is to tell the ecu to retard timing, so I do not want to alter it in any way. I know I need a resistor and then an amplifier, but which ones will match and how can I build them?
2. How can I make the led stay on long enough to see it? The signal may be very fast, I dont know yet. I would like some kind of time delay for the light, so it will stay on for 1 second each time it sees any voltage from the yes/no signal.
As you can probably tell, I am new to electronics, but I plan to follow this board a lot and hopefully pick things up quickly.
Thanks!