Is there such a thing out there (relay) that when receives an intial pulse it switches closed and stays closed. Then when another pulse is received it opens and stays open?

I am thinking about wiring an unused accessory (wire and button) from a remote starter to an electrical device that I would turn on with a push of the remote, then could turn off again with a push of the same button.

Thanks!
Ryan

__________________
2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

There are.

Such a product is marketed for custom motorcycles to run the headlamp (high/low beam). It's actually a double-throw relay, but you can ignore one of the contacts. The size and contact location is just like the other ice-cube relays that you've seen.

This is the exact piece that I used on my Shovelhead:

http://www.foghollow.com/cgi-bin/catalog_new.pl?fid=988645183.104006&query=Category%3DElectric%26Description%3Drelay%26PartNo%3D%26pagenum%3D1%26cgifunction%3DSearch%26s ubmit%3DSearch&cgifunction=form

Oh, a warning. The included wiring diagram is wrong. I can tell you how to connect it if you decide to get one and the error is not obvious.

You can combine a D or JK flip flop chip with a relay and accomplish this. The chips are #4013 for the D and #4027 for the JK. Either will work and both will accept a 12v power source.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

I considered that route, but buying a $30 relay was easier and more reliable.

I had no idea such a nifty device existed...

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

And no key debouncer is needed with it, whereas the D or JK approach certainly would.

I had a momentary contact switch (from the relay pin to ground) on the handlebar which I hit to flip the beam between low and high beam.

Yeah, I didn't think that the mechanical switch might send a "dirty" square wave signal that would have to be cleaned up going into the input.

It's funny, I still have and refer to my 30 year old Forrest Mims electronic handbook...

Priceless!

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

Just to make sure I'm clear (probably for my own clarification, but just double checking I guess)-

I would have the following wires going to the relay
12V
Ground
To Accessory Component wire
Wire from Remote Starter

The relay would be normally open. Then if I wire it correctly, I push the button on my remote triggering the relay to close and the relay stays closed even though it is not receiving a continuous signal from the control unit. Then I push the same button again and it triggers the relay to open.

Does that sound about right?

The picture of the relay you show has 5 terminals, would one be left empty?

Thanks Matt!

What year is your shovelhead? My best friend has a 78. His dad bought it new when he was a Harley mechanic then passed it on to him when his dad bought a new one. Now it pretty much sits as he bought a V-rod in 2006.

__________________
2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

One detail, Graplr. The relay input lead must be shorted to ground to switch the state. If your device shorts to ground upon activation and can handle the current, you can wire it up directly. It may be possible to wire the relay so that it takes a +12V source to switch the state; I don't remember.

Otherwise your analysis is correct. The other lead is opposite of the one that you'll be using. I used one lead for the low beam and the other lead for the high beam.

Whatever you do, be SURE to install a diode between the relay coil leads.

My Shovelhead was a '74. It is no more.

They are called latching relays. You can search for them by that name.

__________________
1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra

By relay input lead, you mean the wire coming from the remote starter? I'm not quite clear what you mean that it must be shorted to ground? Do you mean that when ground is applied, this activates the switch?
I guess I'm confused by what you mean when you say 'shorts to ground'.

I assume I shuold install a blocking diode which prevents the current from flowing backwards?
Sorry to hear that.

__________________
2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

Thanks. This is one I found for cheap. Look fine?
http://www.jbr17llc.com/vsm129-latching-universal-relay-1212912.html

__________________
2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

By "shorts to ground," I mean just that. If you were holding the bare wire from the relay, you could touch it to ground to switch the relay state. But you can probably wire it either way (active hot or active ground) as long as you have enough current available.

The diode is to prevent the EMF generated by the collapsing field from damaging the electronics upstream, when the coil current is switched off. It's installed in parallel with the coil.

Ha, collapsing EMF. Makes me think of stuff my dad and his friends when he was younger. He was a plant systems engineer and he would throw open the manual contactors for large electric motors as fast as he could just to see how far the arc would shoot off the contacts...

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250