Help and suggestions for a motorcycle LEDs project

[CancunManny]

Hello Arduino users!

I had some amazing help last time around with a project and hoping I can have the same luck again.

I just purchased a new motorcycle (Pulsar AS200 Red) and I want to personalize it with LEDs. However I don't want to go with the regular taxi driver in Cancun look, where they just glue the strips on.

I am thinking of two projects. The first is much more straight forward which I can probably do on my own, but would like any input and suggestions.

This first project consists of 20 5 mm amber LEDs (10 on each side) as turn signals, and about 20 5 mm red LEDs, as rear lights and break lights. (I do know I will need a large resistor for the blinker on the bike to work)

I plan to use a 12 v to two 5v 3A USB female connectors converter which I should be able to plug straight onto my motorcycle. From what I understand the motorcycle output is not a steady 12v but the converter does output a steady 5v so I don't have to worry about that anymore.

The questions I have that would help me out would be:

1. Should I put a resistor to each LED (doing the math for the right size), or can I get away with perhaps using only 2 resistors, one to drop from 5v to the right v's for the red and another for the amber, and just connect them parallel accordingly. Or would a combination of both be best, serial 2 or 3 leds plus a resistor to work out to 5v.

2. For the red LEDs, when I turn on the lights I would like for the leds to light up to 50%, and when I turn lights off for them to go off, but when break lights go on, for all leds to light up 100% regardless if lights are on or off. I was thinking of using the license plate light (which turns on and off with the lights) with extra resistors to lower the Vs enough to light up the red lights half way, but at the same time also have the break light connected to all red Leds, but with resistance to light reds 100 %. Would this work, or if lights are on (50%) then I turn the break lights on (add enough power to get to 100% on its own) the energy would add up and I would burn the Leds? (basically LEDs connected to two positives, one with lower voltage than the other)

The other project is the fun one, using an arduino. My last project (which was my first project) I created my own arduino instead of using a pre made one. For this project I will splurge and I do plan to use an actual Arduino Uno R3.

With this project I want to control about 80 Leds. Plan to put about 30 to 35 in the front windshield, embedded into the edges of the plexiglass. About 15 to 20 on each side panel behind some metal grills embedded onto the plastics. And about 5 to 6 leds on each side of the rear fender.

Undecided on the color yet. The bike is Red, I am on the fence between Red and Blue leaning a bit more towards the red. Both my GF and a good friend of my think blue would be nicer. What do you guys think?

I plan to use the arduino plus 2 TLC 5940 DIPs to control them. Each TLC can handle 16 Leds, so with two up to 32 at one time, since I am talking of up to 80 I would multiplex (if that is what is called). Would this be the advisable way of doing it?

To control the Leds/sequences I plan to use two toggle (on/off) switches and a push button. I plan to use the on/off switches to create 4 options (0,0 0,1 1,0 and 1,1), and have those switches control the function of the push button. Something like:
0,0 push button cycles through light density (very low, low, middle, high, very high)
0,1 push button cycles through animation speed
1,0 push button cycles through programmed animations, that use density and speed already set
1,1 push button cycles through custom animations that already have the density and speed of animation programmed in.

Is there a better way to accomplish what I want, or is that a good solution?

As an extra, would there be a way to use the push button, pressed for longer than x seconds to turn the lights completely off and on, or would I have to introduce another switch for that?

[OldSteve]

I'll answer this one for now:-

1. Should I put a resistor to each LED (doing the math for the right size), or can I get away with perhaps using only 2 resistors, one to drop from 5v to the right v's for the red and another for the amber, and just connect them parallel accordingly. Or would a combination of both be best, serial 2 or 3 leds plus a resistor to work out to 5v.

If the LEDs are parallel, you need one resistor per LED.
If you have series strings of LEDs, one resistor per series string is fine.

[OldSteve]

For dual-brightness LEDs, you could use a variation of this:-

When one switch is closed, the LED current is 10mA, when both switches are closed, the LED current is 20mA.
For human eyes to perceive the brightnesses correctly as half or fully lit, different resistor values would be needed due to the eye's logarithmic response, but this is a basic example. (Using a 20mA LED.)
The switches represent transistors or similar.

You could also use PWM to effectively control the brightness, of course.

[CancunManny]

OldSteve:
For dual-brightness LEDs, you could use a variation of this:-

When one switch is closed, the LED current is 10mA, when both switches are closed, the LED current is 20mA.
For human eyes to perceive the brightnesses correctly as half or fully lit, different resistor values would be needed due to the eye's logarithmic response, but this is a basic example. (Using a 20mA LED.)
The switches represent transistors or similar.

You could also use PWM to effectively control the brightness, of course.

Thank for the input. For the blinkers and break lights I wanted to do it without much electronics, as basic as possible. With your example, with the lights "off", when ever I turn on the breaks they would only go 50%, not what I was looking for. But your suggestion did help me out, since I did some reading on light perception for humans, seems I can get away with running the "lights" with 5 to 10 % of its maximum current (they would look dim), then running the stop lights at 90% maximum current. At 90% they should look fully lit to the human eye, and if lights are on as well, the extra 5% to 10% would keep me under the maximum current limit.

Is it as simple as that? Can I have one LED with two positive sources connected at the same time?

[OldSteve]

CancunManny:
With your example, with the lights "off", when ever I turn on the breaks they would only go 50%

You're too quick to dismiss an idea.
I did say "a variation of this". I was just showing the basic method. I didn't know your level of electronic knowledge.
Since there will be many LEDs, this time I've also included the necessary transistors:-

The values of resistors, transistors and diode are dependent on the amount of current. For now I still showed the LED current-limiting resistors for a 20mA single LED.
(Not chosen for the human eye response. Some testing would be needed.)

A dual-voltage supply would just be over-complicating things, requiring two supplies and 'high-side' switching. KISS.

NB This still won't do exactly what you want, but shows the basics of the method. Multiple LEDs would require a bit more thought, but would be along similar lines.

How many LEDs do you plan to use? For a large number of LEDs, it might be worth considering the dual-supply method, but for a small number it's not necessary in my opinion.

Low side single supply multiple LEDs:-

High side dual supply multiple LEDs:-

[CancunManny]

Hello, and sorry if I came across as not appreciative or dismissive. I have little to no experience, but I do like to research as much as I can before asking questions. Then when I ask questions I try to get the info that I get and do some more reading on my own. I didn't know what a transistor was, but just looked it up, and it is similar to a relay switch. In lame terms with the transistor gets the positive signal it connects the ground closing the circuit. And I do think I do have access to some transistors locally (besides not being very knowledgeable getting parts in Cancun is hard.)

Plan to use about 10 to 12 Amber leds per side, and about 20 to 30 Red Leds for tail lights/break lights. Contemplated using some of the reds as tail lights, and some as break lights, but I think dim for tail lights, and bright red for break lights would be a much nicer look.

Thanks again for the input

[OldSteve]

For 30 standard (20mA) red LEDs, the total current with brake light activated would be 600mA.
The "low-side" circuit would work, providing the right transistors were selected for he current, (or MOSFETS would be even better), and the resistor that I've labelled as 220 ohms would work if it was a 10W wirewound resistor to dissipate the heat generated by the voltage drop. If higher-current LEDs are used, this method might not be viable.

Alternatively, the "high-side" circuit would work fine, if a small 'switching' DC-DC converter was used to drop the 12V supply to the lower voltage for the tail light. (One on the higher-voltage supply would be good too, to keep it at a constant voltage. You could then use, for example, a 10V supply for brake light and a 5V supply for tail light, and select component values accordingly. (The DC-DC converters could be adjustable, allowing you to easily set a suitable brightness for the tail light.

Doesn't your bike already have tail and brake lights?