VVT control relay driver

feck · Post by **feck** » Mon Oct 02, 2006 11:32 pm

First things first.
MS1 on V3.0 board running MSnS-e (Version yet to be decided)

I am simply after some clarification/reassurance on the mod's required on the board to use the LED circuits to drive an external relay. I have spent hours searching posts and the Megasquirt websites and have ended up here. Please point me in the right direction if this is already written up somewhere.

I am looking at swapping the 2n3904bu (100mA) transistors for ztx450 (1A) transistors, the same as the FIdle circuit uses, and running a wire from the -ve leg of the LED out to one of the spare output pins. I will also install a protection diode accros the relay coil. Will this be safe enough? Will the transistor be all that is likely to get cooked if something goes wrong.

Cheers,
Daniel

feck · Post by **feck** » Mon Oct 02, 2006 11:43 pm

Naturally I think I just found the circuit I am after here:

http://megasquirt.sourceforge.net/extra/waterinj.html

FoundSoul · Post by **FoundSoul** » Tue Oct 03, 2006 5:16 am

While that would likely work just fine the docs for relay control with MSnS-E are here and this works just fine: http://megasquirt.sourceforge.net/extra/outputs.htm

I have a simple little kit with the parts needed here if you want it, or you can pick the parts up locally I'm sure... http://www.DIYAutoTune.com/catalog/pcbv ... p-126.html

This will drive a relay and MSnS_E will let you trigger the output based on any of several variables (RPM, CLT, IAT, MAP, etc) with Hysterysis control so you can dial in just what you need.

feck · Post by **feck** » Tue Oct 03, 2006 8:28 am

Thanks Jerry,

I don't know how many times I looked at that page without seeing the circuit diagram down the bottom. Should be all go now.

Cheers,
Daniel.

FoundSoul · Post by **FoundSoul** » Tue Oct 03, 2006 8:30 am

No problem Daniel!