Swap between two colors without an additional light?

Question

A Quick Note

I'm not sure of a more accurate name for this question. If you can think of a better name, feel free to edit and change the name. Also, I'm not the greatest with technical terminology so please forgive me if I'm not explaining something correctly. If you need clarification please ask and I will update the post.

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Legend

• T = Top
• B = Bottom
• L = Left
• R = Right/Rear

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Overview

I currently have two other posts (here and here) related to this one, both solving different issues. This is a new issue, and the idea seems rather complex to me. This is an in depth lighting kit for my car. It involves a multi-function light, under glow, interior lighting, engine bay lighting (via the hood), and grill lighting.

I have eight LED strips that each have the following four wires:

• Positive
• Negative
  • Red Channel
  • Green Channel
  • Blue Channel

Four of the LED strips (engine bay and grill) are wired together to come on as a single entity displaying purple so the hookup is:

^{simulate this circuit – Schematic created using CircuitLab}

The other four strips are located under the car along each edge. Currently, three of those are wired together to display purple with the fourth connected to the brake light displaying red:

This is where I begin having a hard time describing things; so please bear with me. The idea is to have all eight lights display purple when the switch is in the on position; and the lights under the car display as follows when the switch is in the off position.

• Bumper (F): White (Hooked to head-lights)
• Bumper (R): Red (Hooked to brake light)
• Side Panel (L/R): Amber/Orange (Hooked to turn signals)

To add to the complexity, I would also like to add in my relays (see this post for details on the relays) to have the side panel lights blink between amber/orange and off, with the turn signals whether the switch is on or off; and if the switch is on, it changes the color to amber/orange and blinks with the turn signals (again in the on/off fashion instead of blinking between amber/orange and purple); then when the turn signal stops completely it turns back to purple).

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My Questions

How can I achieve most (if not all) of the above?

I believe I may be able to use jumper wires to route the signal but I'm afraid this will cause white lights when the switch is in the on position.

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Notes

• I prefer all of this to go through my single switch if possible.
• My car is a 2016 Mitsubishi Lancer.

Answer 1

8 relays, plus 8 diodes for full features.

^{simulate this circuit – Schematic created using CircuitLab}

You can probably reduce the number of low end relays, if you run 6 ground wires back to a single relay (Brake Blue, Front Green, Both Turn's Blue and Green). And if you don't want the brake or headlight leds to turn on with the existing brake or headlights, you could remove those as well.

^{simulate this circuit}

Frankly, I think it may be cheaper and simpler to have two sets of led strips, with a single switch controlling which one gets power. Less wires to run, less relays to buy and wire up.

Answer 2

• Bumper (F): White (Hooked to head-lights)
• Bumper (R): Red (Hooked to brake light)
• Side Panel (L/R): Amber/Orange (Hooked to turn signals)

Let's create some truth tables:

Table 1: Front lights.

                        Front
Switch  Brake  Turn |  R    G    B  | Notes
--------------------+---------------+---------------------------
  On      x      x  |  1    0    1  | Purple.
  Off     0      0  |  1    1    1  | White.

Table 2: Side lights.

                        Side
Switch  Brake  Turn |  R    G    B  | Notes
--------------------+---------------+---------------------------
  On      x      x  |  1    0    1  | Purple.
  Off     0      0  |  1    1    0  | Orange (dim green?).
  Off     0      *  |  *    *    0  | Blink in phase with turn.

This one is the problem.

Figure 1. Timing diagram for turn signal.

                     _   _   _   _   _
Turn signal: _______| |_| |_| |_| |_| |______________
             _________   _   _   _   _   ____________
Side:                 |_| |_| |_| |_| |_|

Table 3: Rear lights.

                        Rear
Switch  Brake  Turn |  R    G    B  | Notes
--------------------+---------------+---------------------------
  On      x      x  |  1    0    1  | Purple.
  Off     0      x  |  0    0    0  | All off..
  Off     1      x  |  1    0    0  | Brake lights.

You should be able to figure out the circuits for Tables 1 and 3 on your own.

Table 2 is the problem. Once the turn signal turns on it has to take over control of the orange strip until the turn signal has been off for longer than the normal 'off' period. I've shown this in exaggerated form in Figure 2.

Figure 2. Timing diagram for turn signal.

                     _   _   _   _   _  ,--- no pulse detected
Turn signal: _______| |_| |_| |_| |_| |______________
             _________   _   _   _   _      _________
Side:                 |_| |_| |_| |_| |____|
                                            `--- sides on

^{simulate this circuit – Schematic created using CircuitLab}

Figure 3. A possible side-light solution.

How it works:

• If SW1, the purple switch, is on RLY2 is energised and the red and blue LEDs turn on. D1 prevents the green LED turning on.
• If SW1 is turned off then red and green are turned on via RLY3. R3 is optional to dim the green to give a better orange colour.
• If the turn signal turns on then RLY3 is energised and disconnects its ground path for the orange lights. RLY3 is a timer with an 'off-delay'. It won't turn on again until the turn signal has been off for a second or two.
• Meanwhile, since the turn signal is blinking RLY1 will blink and switch the orange lights on in synch with the turn signals.

Remember that you require two of these circuits.

Is it worth all the hassle? Maybe but that's the price of being cool. Maybe someone does an electronic kit for all this without the need for relays.