View Full Version : Jaycar Kits
06-09-02, 09:08 PM
Hey fellas, I need to build a Square Wave signal generator but i don't want to $25 for a Manual i will never use again.
Does anybody have the "Short Circuit 3" book, if so could they scan the circuit diag for Project 30.
I would greatly appreciate this.
06-09-02, 09:31 PM
:wtf: r u talkin about?
06-09-02, 09:34 PM
Someone who has the book or built a Jaycar kit would not ask this question.
Therefore the question was not directed at you.
06-09-02, 09:38 PM
what i soughta meant, is what is it? Some sought of electrical advice i guess, Im here to learn,
06-09-02, 09:46 PM
Here is the Lowdown,
EJ20TT engine wants a speed sensor input to make the twin turbos stage correctly. Problem is the engine is infront of a 2Lt Kombi Gearbox.
Therefore we need a 5 V square wave input that comes on when the vehicle is moving.
We will try actuating it with a Micro switch on the throttle body and see how that goes.
The kit seems an easier way, rather than splitting the speedo drive and using the genuine subaru speed sensor.
For $13.00 you can only try and fail??
06-09-02, 09:47 PM
k thanks now i have more of an insight on what ur talkin about. sounds tricky
08-09-02, 05:06 PM
u could use a 555 timer to output 5v sqaure waves, it just keeps oscillating as soon as u give it power so the microswitch could be put in series with the supply of the 555.
i will draw u a diagram, ok here it is, 50%duty cycle oscillator, and the output it gives. (note: R3 resister on the output was only put there so it would simulate, u would hook that up to the input of the comp, it should be alright to go str8 to the comp i dont think the comp would sink alot of current).
here is the diagram
*edit* forget to mention that with the current values it oscillates at about 1.4khz)
08-09-02, 05:06 PM
the output :)
08-09-02, 05:14 PM
so the 555 outputs a 5v wave thing, u have to give it 5v, this can be done with a 5v regulator.
78L05 (100mA) should be plenty for it :) and according to altronics its only $1.00
i went through and found prices for all of em in da altronics catalgoue.
555 - 1.70
resistrs - 0.80 (only buy in packs of 10 at 0.4c a pack)
caps - 0.30
voltage reg - 1
10-09-02, 09:37 PM
Thanks for that. We have all the components, so i'll keep you informed on how it goes.
11-09-02, 11:49 PM
heh i made a mistake in the price for a 555, i accidently got the price of the CMOS timer, and i shoulda got the price for the NE555 timer (which is $1.00).
sorry bout dat.
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