Electronics question

[450Nick]

I was just wondering, I'm looking to get hold of a toggle switch that switches two channels in three modes. This is to set my ECU map, so one side of the switch needs to tell the ECU by way of varying voltage (0, 2.5 or 5v) which map it should use. The other should light up the corresponding LED on my dashboard to tell me which one is active. I've looked all over the place but can't find any such toggle switches... Do they exist? If not, how else could I make this work?

Thanks,

Nick

[TheEnd]

A three way switch with a 5v feed, and a resistor on the middle option to drop the voltage to 2.5v.

ie, so you switch is off, on and on, the 2 ons will drive a 5v LED very easy, then after you put the resistor on one to get 2.5v, but you might need something a little more clever to get the 0v to light an LED when it'll always read 0v on that output anyway

[DIW35]

Would a dpdt, centre off switch not do the trick?

[450Nick]

Yes, I suppose it would, I'd just need to put some thought into lighting an LED in the off position... I'm sure its possible though if three way on switches don't exist!

[JimNoble]

Reckon this would do it:



Switch is DPDT.

R1 should be appropriate to the input impedance of your ECU (connect the ecu input to the o--)

R2 should be 5v-(LED forward voltage drop)/(desired LED current)

The LED is one of those tri-colour efforts with, say, red and green LEDs in a single package. So you'll get Yellow for centre switch position and either Red or Green when switched up/down...

(Caveat - Don't blame me if your ECU blows up; I don't normally deal with components this big )

Jim

[Zad]

Or use a 3 way rotary switch? They also do 4-way, 6-way and 12-way. At the grand cost of £1:79 at Maplin (excluding knob, so to speak). The 3-way one has a total of 4x3-way switches in one, plenty spare to do with what you will (the 4-way has 3, the 6-way has 2 etc)

http://www.maplin.co.uk/module.aspx?moduleno=2417

They used to do multi-way slide switches but I can't see them now.