View Full Version : megasquirt shift lights how to

05-04-2007, 05:19 PM
After recieving a few requests I've put together this how to on putting sequential F1 style shift lights into your volvo with Megasquirt.

more info on the shift light can be found here: http://megasquirt.sourceforge.net/extra/shiftlight.html

Disclaimer: all of the following information worked for me. If you blow up your car or fry your megasquirt while doing this don't come crying to me. Proceed at your own risk. ;-)

Parts List:

Before you begin to build your shift light system you're going to need a few things. The easiest and cheapest way for me was to get most of the stuff off ebay. If you have a local hookup thats great, for me there was only The Source with major markup.

- 1 x Megasquirt (you should already have this)
- 4 x 1k ohm resistor
- 5 x 1N4001 diode
- 3 x 2N2222A transistor
- 1 x matrix board (aka something to build your circuit on)
- 6 x led and corresponding resistors (you must calculate this based on you setup)

For most of this stuff I used a store on ebay called resistorsplus. Prices were fair and I only bought what I needed. I sourced the led's locally from The Source, price wasn't too bad but they can be had for cheaper online.


This is where you can get creative, color choice and placement of the leds is entirely up to you! As for me I decided to place the leds in the lower six squares of the cluster in my 242. If you're going to go this root like me be aware that you will lose the following warning lights:

- oil pressure idiot light
- battery idiot light
- lamda sond indicator light (if equipped, who cares you have MS now!)
- OD idicator light (M46 only)

Now if you're like most t-brickers you won't care about the oil or battery lights as you already have the appropriate gauges to the right of your main cluster to keep tabs on things. I'll go into more detail about moving your OD indicator light later for us M46 users.

Remove the cluster by removing the light switch and two square panels immediately to the right of the cluster. You should now see four philips screws, unscrew them now. Make your life easier and remove the steering wheel. Reach up from underneath to release the speedo cable them pull the cluster out. Start by removing all the indicator lights that are already in place. Also remove the film with the little pictures on it by disassembling the cluster. Real easy six screws around the perimeter and pull apart.

I found the bare leds to be too bright, so I place a piece of transparent plastic in front shown here (remember recycling is cool):
Now decide how you want the lights to come on. For me I chose to have the first stage on the outside and progress towards the middle. You could go left to right, right to left doesn't matter this is where your creative juices can flow. Mine will go like so:

I mounted the leds to some matrix board cut to size and then glued the matrix board to the back of the instrument cluster. Depending on what leds you use and where you pull your power source from, you'll have to calculate the appropriate restistors to use. Regardless you should end up with something that looks like this:
Here you can see that I used a nice harness stolen from an audi for quick disconnect should I ever need to remove the cluster. I'd recommend some kind of disconnect to save from headaches down the road. Also make sure to test all your leds before you put the cluster back in for good.

M46 users
Placing the leds in the cluster like this will eliminate the OD indicator light. Luckily there is an easy fix. The most extreme right light in the cluster is an OD off light used on automatic cars. I used a sharpie to block the "off" part of the transparent film. Another option would be to cut your existing green OD film and place it is the "OD off" spot. I managed to break mine while cleaning so I went the sharpie root for now.

The OD indicator light is activated via the yellow wire in the main cluster harness. From memory I believe it is pin 4 but you should check to make sure on your car before you go cutting wires. Once you find the correct wire, cut it from the harness and place female spade connector on the end. Next plug the spade connector onto the back of the cluster as shown in the picture:
Now your OD indicator light has been moved to the opposite side of the cluster! Its as easy as that! :)

Logic circuit

Now that you have the leds all together we need a circuit to tell the leds when to turn on. The Megasquirt n Spark Extra page shows a layout of the circuit. Note that this circuit is WRONG! DO NOT use this diagram as I'm told your leds will constantly be lit at half intensity. The correct diagram looks like this:
This is a fairly simple circuit with 4 inputs and 3 outputs. For all of the inputs I tapped into the back side of megasquirt. The 3 outputs go out to ground out our leds thus turning them on and off.

-5+ volts (pin 20)
-grnd (pin 19)
-pin 10 (pin 10)
-pin 11 (pin 11)
I passed the wires through some unused holes in the board as I placed my logic circuit inside the main case of megasquirt.

-low stage
-medium stage
-high stage
Since I place the logic circuit inside the MS box there are only three wires coming our of MS that go to where ever you have decided to place your leds. In the end you should end up with something similar to this:

So there you have it the hardware requirements are done! You'll have to set your parameters in Megatune now. This is dead easy: go to More Settings > shiftlight > from the pulldown turn it on and set your upper and lower limits.

That's it! You're done! Now go out and do your best MS impression, and by MS I mean Michael Schumacher in this case:rofl:

Additional pics can be found herehttp://forums.turbobricks.com/showthread.php?t=96552

05-04-2007, 05:21 PM
wow, nice write up.

05-04-2007, 07:08 PM
Nice write up.

Moved to article composition.

05-04-2007, 10:06 PM
Those blinking dash lights look so disco, I love it, I might do this down the road.

08-23-2008, 05:41 PM
Hate to resurrect a dead thread, but I'm in the middle of doing this to two cars (mine and a customers) and I'd like to use the green and red LED's as dual function indicators, green (dimmed slightly) for a launch control active indicator light, and the reds for knock indication. Green for go, red for stop, kinda makes sense in my head.

Question is: do I need to add a diode in each circuit for back-flow resistance?