Footwell toggle switch for Lidatek power switch?

[David T]

My Lidatek LE-30 is on it's way and been thinking about the install. Anyone know if I can use the footwell light toggle switch (996.613.980.00) in place of the power switch that is provided with the system? Here's the schematic: <http://www.lidatek.com/gfx/LE-20_schematic.gif>

Since it will be ON most of the time, I'm thinking that I could have the the switch illuminate when the unit's turned off.

Does this sound possible?

Thanks,

David

[Tool Pants]

All dash switches are momentary. As soon as you take your finger off it will return to the neutral position and there will be no power to the Lidatek. You would have to use a relay with the Porsche switch to do what you want.

[David T]

That's what I was afraid of. Very little memory of my EE courses left, so can anyone give me some detail info on how the relay thing could be done?

TIA

[Sandy]

Jeff is correct. To obtain a hard ON & OFF function from the momentary-action FWL switch contacts requires a latching relay circuit.

Here's a mechanically-latching relay I obtained from Digi-Key. It's an OMRON MY2K-US-DC12 (Digi-Key Z2056-ND). It cost $14.20 and is quite useful for many 12 volt circuits that are controlled by switches with momentary contacts. The DPDT contacts can handle at least 3 amps. The latching and unlatching coils draw only 60 ma. and 120 ma. at 14 volts. They draw current only while the FWL switch toggle is being pressed. The relay then REMAINS in the position it was toggled to, drawing no current.

The image shows part numbers for a relay socket and retaining clip for mounting the relay on a metal bracket or chassis. A 25 mm. x 22 mm. cutout is required. The socket cost $1.36 and the retaining clip $1.38, locally. Radio Shack doesn’t carry equivalent hardware.

The socket could be eliminated, because the relay's pins have small holes in their tips for securing wires. If you're skilled in basic soldering, you should have no trouble soldering connecting wiring ends onto the pins. Use short lengths of heat-shrink tubing for insulating the soldered connections. I would think that the relay, without a socket, could be mounted near the FWL switch using Velcro, or double adhesive-backed foam tape. I've run some tests with the relay and it seems extremely immune to vibration.

I've included a suggested relay hook-up diagram below. It includes connections for the FWL switch's nite illumination LED. The amber annunciator LED in the FWL switch will illuminate when the relay is in the RESET (OFF) position. This is the relay position that will remove power from your device.

The "consumer-switched-off" bus coming from the alarm C.U. provides switched +12 volts to the rear window defogger switch on a RED/BLACK wire. That bus powers all the interior lights and is handy to tap into for powering the FWL switch LED and the latching relay coils. The bus goes dead 10 minutes after locking the car, or after 2 hours, if you don't lock-up. Another option is to tap switched power from the GREEN/BLACK wire of the telephone prep. connector under the forward, center console. You might want to do this if you're concerned about the amber LED in the FWL switch remaining illuminated for awhile after leaving the car. The LED draws a negligible 20 to 25 ma.

If your device draws a large amount of current, the +12 volts input that is wired to relay contact 11 may need to be obtained from a separate, fused, ignition switch controlled source, such as the telephone prep. connector (GREEN/BLACK, 7.5 a.), instead of the RED/BLACK source.

[David T]

Excellent! Thanks a lot Sandy. That's exactly what I was looking for.

David

[Sandy]

Here's some additional info about the latching relay, which I meant to include in my reply:

The relay appears quite large in my image, but actually measures only approx. 1 & 5/8” (including the pin length) x 1 & 1/16” x 13/16”. When plugged into its socket, the length of the combo increases to 2 & 1/8”. However, the socket pins can be bent over easily and unused pins clipped off to shorten the package slightly.

You can always tell, visually, which position the relay is in. It has a little red-orange, rectangular flag inside its case at the top. You can see it at the corner of the white placard. When the relay is in its SET position (opposite the position I drew the relay contacts in my diagram), the flag comes into view. When the relay is in its RESET position, the flag disappears from view.

[C4 Pazzo]

Sandy,

I just wanted to say "thank you" for posting the diagram of the latching relay and footwell light switch (way back in June). I was banging my head against the wall trying to use a four pole double throw latching relay with the footwell light switch to switch between the cd changer and an iPod. After searching Renntech and finding your diagram, I was able to get it working in minutes, including both the nite illumination LED and amber annunciator LED. Fantastic!

Thanks.

C4 Pazzo

[drpeter]

C4 Pazzo,

I used this set up, yet was unable to get night illumination and the amber on/off light. I was advised to pull the footwell switch cover off and put it on a TT spoiler switch...... Is that what you did, or did you have a different answer?

[redduck996]

dumb question, what's a lidatek le-30?

My Lidatek LE-30 is on it's way and been thinking about the install.  Anyone know if I can use the footwell light toggle switch (996.613.980.00) in place of the power switch that is provided with the system?  Here's the schematic:  <http://www.lidatek.com/gfx/LE-20_schematic.gif>

Since it will be ON most of the time, I'm thinking that I could have the the switch illuminate when the unit's turned off.

Does this sound possible?

Thanks,

David

<{POST_SNAPBACK}>

[Loren]

Laser radar jammer

[C4 Pazzo]

drpeter,

I used an unmodified footwell lite switch, along with a four pole, double throw latching relay to switch between my cd changer and an iPod. For the nite illumination, as shown on Sandy's diagram, I connected position 3 of the footwell switch to the grey/blue/brown wire connect to the PSM switch. For the positive switching voltage, I connected position 4 of the footwell switch to the red/black of the rear defogger switch. By connecting position 5 of the footwell switch to the common spot on the fourth pole of the latching relay, and connecting the corresponding spot of the fourth pole for the iPod to ground, the annunciator lite goes on when that position is selected. It is important to make sure the positive power source is either a switched source or one (like the defogger) that shuts off after a period of time so as not to drain the battery if the car sits for a long period of time with the annunciator lit. I needed to use a four pole latching relay, since I used three poles for the left, right and ground channels for the audio switching.

Edited January 2, 2005 by C4 Pazzo