Building a stimulator

[Richard M]

Wayne,
Assuming the 2-wire sensor is variable reluctor type which generates AC
signal, you should find you can get away with capacitor-coupling your signal
to the ECU inputs.
The ECU will normally detect the rising portion of the waveform and then
trigger off the zero-crossing point as the signal falls on it's negative
swing. (The zero-crossing point coincides with the condition where the
rotating target is directly in front of the sensor).
The issue here is that the input signal actually swings negative to a
degree, so the ECU can detect the zero-crossing; the waveform shape is
generally of little consequence, although it will have an effect on how
'wide' the conditioned sensor signal is internally in the ECU.
Experiment with capacitor coupling with various capacitor values and maybe
bleed resistor values (to discharge the cap.). It may also be beneficial to
experiment with the width of your squarewave input pulse.
Hope this helps.
Rich

----- Original Message -----
From: "Wayne Macdonald" <wmcdonal at optushome.com.au>
To: <diy_efi at diy-efi.org>
Sent: Tuesday, April 09, 2002 1:24 PM
Subject: Building a stimulator


> I am building a stimulator to run a Sagem ECU on a test bench, I want to
> generate the crank trigger from a micro but I am having problems.
> The ECU expects to see a waveform from a normal two wire crank trigger,
The
> square wave I am generating does not seem to fool the ECU.
> Can someone help me with the circuit required to convert a square wave
into
> a sine wave.
>
> Thanks
>
> Wayne
>
> --------------------------------------------------------------------------
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