Going from 0-12v Square Wave to 0-5v Square Wave (Help.)

[WheelWhore]

Car produces 0-12v Square wave reading but the cluster i have needs to see 0-5v Square Wave.

Therefor, my tachometer doesnt work.

Can anyone explain to me how I can drop it from 0-12v to 0-5v coming from the ecu to the tach?

I have read about voltage dividers and zener diodes, but this is all french to me...... I am a pictures kinda of person.

Thanks in advance.

[jp's red240]

Zener Diode as Voltage Regulator Tutorial (http://www.electronics-tutorials.ws/diode/diode_7.html)

[rat240]

You can use a 5v regulator you may need a heat sink
How many amps does the cluster draw
RadioShack (http://m.radioshack.com/radioshack/product/detail.do?itemId=2062599&op=%22http://www.radioshack.com/product/index.jsp?productId=2062599%22)

The 3 pins
Are input,output,ground
The output would go to postive lead on the cluster

[Ilya]

------12v-square_wave---|_|___|--------|_|___|-----5v-Square_Wave----
....................................4.7V Zener 2.7V Zener

So put two zener diodes in series like the picture above, make sure you get those exact values and make sure the lines on the diodes are pointing at the 12v side.

The voltage regulator is also an awesome idea, but requires a ground pin, and depending on the frequency of the square pulse, may be to slow to respond

[WheelWhore]

Cool, thank you very much guys. I will post a pic of the cluster in the car when its done. :)

Ty again.

[WheelWhore]

The 3 pins
Are input,output,ground
The output would go to postive lead on the cluster

Is that left too right configuration?

Here is the one I just bought. Would have went the Zener route but my RS didn't have he right ones. :(

http://i778.photobucket.com/albums/yy61/94egcoupe2/IMAG0629_zpsd904ac89.jpg

[niscur29]

Could not have found this thread at a better time. My MSD LS controller outputs a 12v square signal. So I can just follow the above instead of wasting 80 bucks on the dakota digital converter box!?

[rat240]

For the 7805 pin configuration
From left to right
Pin 1:input
Pin 2:ground
Pin 3:output

[WheelWhore]

^~thank you much. :)

[Ilya]

Could not have found this thread at a better time. My MSD LS controller outputs a 12v square signal. So I can just follow the above instead of wasting 80 bucks on the dakota digital converter box!?

Yes, but depending on the frequency of the signal, the voltage regulator may take too long to saturate to provide an output voltage, however, 5 dollars for two ideas and a few minutes of your time is much better than wasting 80 dollars and adding a ton of wires to your car. Good luck and keep us posted!

[OnTheChip]

Could you use a simple 2 resistor voltage divider?

[WheelWhore]

^~From what I have read, Yes.

[WheelWhore]

BTW, the Voltage Divider worked flawlessly.

[Danial]

Awesome info in this thread, you should definitely do a writeup when you are done. I know so many people that run no speedo because of this issue.

[WheelWhore]

The thing is, I put a NX cluster in a EG Civic. I dont think a writeup would help many people. :)

Plus, this is just for the tach signal.

Havent solved the speedo problem yet.

[Danial]

I meant tach sorry haha.

[Frank_Jaeger]

The thing is, I put a NX cluster in a EG Civic. I dont think a writeup would help many people. :)

Plus, this is just for the tach signal.

Havent solved the speedo problem yet.

We've been duped!

[WheelWhore]

Going in reverse, does that count a rwd?