As an alternative to the Auto S/S kill switch that is described on post #1 of this thread, the following design uses a different "programmable" module that is readily available from the net. The "Multi-Functional Delay Timer" (MFDT) can be programmed to undertake 17 x different timing functions, but as used in this design, the inbuilt function #7 performs the exact timing characteristics that are described in post #1 of this thread.
The MFTD can be purchased from EBay and Amazon (see link below), or it can be obtained directly from the distributor via the last link below:
Multi-functional Delay Timer
The MFDT has 6 x wires as shown in the diagram below:
As indicated, the device has the same four wires as per the original Mono (i.e. Vcc, Earth, Vout and Trigger) plus it has two additional wires that are used for programming the T1 and T2 timing periods.
The circuit diagram for the MFTD unit is shown in the diagram below:
As indicated, the connections are the same as those for the Mono except that the Trigger wire is not used and the two programming wires are not connected (these wires will be used later). Also, the "freewheeling" diode across the relay coil is not required because a diode has already been included for this purpose inside the MFDT.
Construction
- Solder the relay (all legs) and the diode onto a small piece of "Vero" board so that the components are mounted on the track side (the relay should be oriented so that "notch" in on the LHS of the board as shown in the Back-view picture below). Before mounting the relay, remember to remove a section of the track where the relay package is to be placed so that the pins on opposite sides of the relay don't short each-other.
- Place a piece of double sided tape to one of the faces on the MFDT and secure the vero board to the other side of the tape
- Solder the Red, Black and Yellow wires on the MFDT to the components on the vero board as per the circuit diagram
- Solder three wires to the vero board for the connections to be made to the centre console switch as per the circuit diagram.
- The three wires coloured White, Green and Blue should not be connected
The pictures below indicate the finished Auto S/S kill switch: Alternate design
Programming Circuit
Using a test bench power supply, or a 12 Volt batttery construct the ciruit diagram below to program the Auto S/S kill switch
Connect a button style switch to each of the white and green wires as shown and connect a LED and series resistor to "see" the pulse signal.
Programming Procedure:
- With the power switch off, hold down the two buttons, then turn-on the power switch and release the buttons. The LED will illuminate for 3 seconds to indicate that the device has entered the programming mode. Keep the power switch turned-on for steps 2, 3 and 4 of these procedures
- Set T1 period: Hold down the button that is connected to the white wire for about 5 seconds. Release the white wire button and the LED will extinguish
- Set T2 period: Hold down the button that is connected to the green wire for about 2 seconds. Release the green wire button and the LED will extinguish.
- Set Mode: The last step is to set the MFDT to Delayed Interval (single cycle) mode - this provides the timing sequence shown in post #1 of this thread. The code for this mode is 7. To set the mode, momentarily press and release the two buttons together - the LED will flash to indicate that you have entered mode selection. Press the white wire button seven times to set mode 7
- Turn-off the power switch - the MFDT is now programmed!
To test the correct timing periods, turn-on the power switch and observe the LED operation.
If T1, and/or T2 need to be re-adjusted, repeat the steps outlined above. (note: there is no need to complete step 4 again - once the mode is set initially, it will remain at the set number).
That's it - Remove the device from the programming circuit, remove the two buttons and secure the unused wires neatly so that they don't short against any other components. Then slip the completed Auto S/S kill switch into a piece of heat shrink tubing and install in the car.
Installation:
Mattaus will describe the installation of the "test device" in his mk7 which has additional buttons in the centre console, but in my MY13 model, there is only one button on either side of the gear selector lever. This means that the T15 power supply wire (Black/Yellow) is not in the wiring loom for the 10 PIN connector to the switch module.
For those in this situation, the additional T15 wire needs to be provided and I found that the most convenient method of doing this was to install a "piggy-back" fuse on fuse position #40 in the "C" fuse box (which is located behind the glove box for those cars that have the steering wheel in the correct side).
Given that I needed to work in the "C" fuse-box area anyway, and because access to the centre console is such a PITA, and because I'm still not certain that the time periods for T1 and T2 are correct (it's therefore likely that I will need to take-out and re-install the device), I decided to mount the Auto S/S Kill switch in the "C" fuse box as well (instead of the cavity in the centre console). To do this, I spliced the two wires to PIN #1 and PIN #4 on the 10 PIN connector and extended these into the "C" fuse box area.
A picture of the complete installation is shown below (note: to minimise the possibility of the device rattling, I wrapped the the completed unit in "bubble-wrap"):
So far the device is working perfectly albeit, I 'm tempted to reduce T1 to about 3 seconds. I'll wait for feedback from Mattaus and AJW before making this change
Cheers
Don
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