light bar

[Cminke]

Hello, I am working on a project to make light-bars for me and my friends.
I have the led's which are labeled as "super bright" so im going to assume 3-5W.
I have MANY questions and they are due to wanting to get it right and not worry about damaging anything, not for thereof lack of knowledge.

Requirements
1) each individual setting must be able to work via physical switch
2) must have flashing, "takedown", left to right, right to left, in to out and left side then right side flashing. MIN.
3) must cost under $50 in parts
4) power source is a 12V 20-40A Pb acid battery
5)must be able to power 9-21 Led's (setups/changes need for for 9, 12, 15, 18, 21 Leds please, not sure how many i will need as of right now )
6) Must have Led lights to show patter in dash (mini leds/low power)
7) must be simple enough to understand and clear. I understand most diagrams but I don't have a complete understanding.


Questions I have:
Do I need a heavy gauge wire?
Will a PCB withstand 12V 20-40A?
How do I avoid blowing a light?


I am EAGER TO LEARN!


emails would be the best form of communication. Connor_minke(at)hotmail(dot)com

 

[KeepItSimpleStupid]

Well for some reason you picks an odd # of lights, so left and right mean what, If there were 8 leds, the you have 4 left and 4 right. When there re 9, you have left, middle and right.

Unfortunately high brightness LED's mean way too many things. So, in some respects, one nneds the LED specs. It could be as simple as Vf=2.1 V a 100 mA, or it could be an assembly designed to operate on 12 V (e.g. LED replacement lamps for automotive) or something absolutely requiring a constant current driver. All can add or subtract complexity.

I think you can use a cascaded LED bar display for the inside.

16 or less makes life a "little" easier"

If you want a quick way out, I'd suggest a PICAXE at www.picaxe.com

I won;t go as far as ssaying use this https://www.adafruit.com/products/732 chip, but i will say one similar to it. As the datasheet says, you can control up to 128 LEDs with 8 of these chips. So, with 8 in the dash and 8 outside, you have used 2 chips.

You then have selection which you did say a physical switch, Rotary? Thumbwheel? or whatever other inteface you want to come up with.

Now some fun stuff like rate, You could use an encoder. It's basically a switch with about 16 detents that you can feel, It can be pressed like a switch and rotated left to right and can have bicolor LED's in the cap. e.g. https://www.sparkfun.com/products/10982

You MIGHT be able to come up with a simple interfce where the color is the mode.
e.g. RED then rotating selects the mode.
When it'ss BLUE it; sets the timing and a LONG press stores the timing info for each mode.

PUSH and ROTATE would select the mode. So, it could go from OFF, RED (select), BLUE (change timing), etc
and possibly a momentary press when off would turn it on.

So, prepare yourself for an interesting learning curve.

Storing settings could increase the complexity a bit. I might consider FRAM memory.

Later, you could get really wierd and make your own patterns.

So, you might be able to "play" sequences. 8 bits of an OR and AND MASK. It might be easier. Don't know,

We need the specs of the LED's and you have to learn programming. The PICAXE is used for 5th graders.

laying out a board, case, power supply and connectors will add up unfortunately.

Alternatively, the pattern # could be displayed in an LED display.

 

[Cminke]

yTHANKS SO MUCH! do you mind if i contact you directly for details I man run into?

 

[Cminke]

I have a few questions perhaps you can answer like you have graciously assisted me with currently.
1)for in dash display could i not run the leds in series to the leds on the external that way each one on corresponds to the one outside? OR is it more recommended to mirror the entire circuit with higher resistors?
2)as far a switches go, im looking for on/off 2 selection military style switches.
3)the led's are single colour and 12v as you said
4)and i choose the # because I have sets of 3's however if you could assist me with 8,10 and 12 light configs it would be much appreciated,
5) im looking at the IC's and which one(s) do i need and what is the proper way to wire them to the led's and program them.

sorry about the newbieness..

 

[KeepItSimpleStupid]

1) You don't parallel LEDS and you don't run different colors in series unless the current is the same. The color changes Vf or the forward voltge and the currents may be different for different colors at the same brightness. The dash light needs to be independent, UNLESS you want to and it's possible to do, tie it to the inversion of BULB out for the drivers. Some high side drivers have the ability to know if the bulb works.

2) So, you mean just one very bizzare sequence (ON/OFF) and no real controls on timing. Once fixed, that's the way it is from the user's perspective.

3) LEDS: Do you have any sort of spec sheet at all. Will you want to control brightness? Do they contain an internal regulator other than a resistor. Something like these: **broken link removed** which require to have a bezel and a socket? LEDs, if not current controlled will change brightness bases on temperature.

This guy, a ULN2003 https://en.wikipedia.org/wiki/ULN2003A or similar, has been used for years to drive stuff. They also make one with 8 sections. There is a max current per package and a max current per pin, so it could be a way to drive the dash LEDS to boost the I2C I/O expander chip. The ULN200x would switch a LED to ground.
The logic supply and the LED supply voltages can be different.

High side drivers https://www.st.com/web/catalog/sense_power/FM1965/SC1037 are ways to drive and protect the load and they can do things like detect a shorted load or an open load. i.e. the lamp is out.

Although I'm thinking ahead of you, but you don't have to. The possibility exists to use <=5 wires or less to control the dash LEDS and <=5 to control the outside LEDS.
An extended I2C bus with power and ground and the drivers. I doubt you want 20 wires to the dash or 20 wires to the outside. Cars now use the CAN bus, but we won't go there.

You may be able to approach the problem as processor with simple LEDs and port (maybe 4); Then expand to an I2c Bus; then add two groups of 4; extend the i2C bus and add your high power string. Just an idea.

 

[Cminke]

okay to touch on a few things mentioned,
the leds are from a former light similer to these,
**broken link removed**
however i dont have a spec on the details of thie led's them selfs, what i will be doing is removig the back ad individualy wiring each led for a better look rather then the coupled lights,

and i plan to have 1 switch for each pattern, i dot care if i have to use 1 board/circuit for each pattern.

i uderstand most of what you said but i am a bit lost with the details of what each thing does, consider me a noob trying to learn hands on

 

[KeepItSimpleStupid]

In terms of flash patterns, so am I. Anyway, just looking here: **broken link removed** I got overwelmed.
With flash patterns, i think of Knight Rider kind of things.

Seems like anywhere from 1 to 3 Amps as an output. So, ball park. Lets; hope you can measure the current that a lamp draws. A multimeter or a multimeter and a shunt or some other way.

There is definately going to be some terminology problems. For instance, a "dash display" already has issues. I'm thinking something like this: https://www.sparkfun.com/products/9937

So, you'll have to learn programming, the PICAXE is programmed in BASIC ans should be very easy to learn. I2C is an inter integrated circuit communication bus that operates at 100, 400 kbps using 2 wires and ground, Typically it's a short bus, but can be extended. The PICAXE has instructions to implement that protocal. NXP defines the addresses of the chips which is how they make money.

So, if I'm making any sense, somewhere you have a controller. a Dash display (indicator) and a high powered display.
So, the Dash display can be one of these I/O expanders and a ULN2003 and possibly something to control the brightness of the LEDS. Dimming from the DASH lights. It's a complication that you may want to plan for.

In the old days, there was a rheostat the brought the dimmed power to the bulbs, Who nows what's used now. That dimmed voltage supply becomes the supply for the indicator. So, simplistically, it looks like a BAR LED display, a resistor for each LED. Powered by the dimmed 12V. The ULN2003 type chip drive the LED and the I2C I/O expander is a serial protocol cal that tells that circuit what lights need to be on. So, you have a small board and hopefuly a Bezel that needs a few wires to do it's dead.
** +12
** High current ground (10 LED (10*20 mA) is like 200 mA)
***+12 Dimmed source or logic DIM or the value of DIM etc.
(there are a few ways to implement dim)
SDL
SCL
Logic Ground
+3.3 or 5 probably

So, it might be 2 twisted pair foil shielded cable and three standard wires. Like an Ethernet cord and just wires.

Getting the I2C bus to operate over large distances is not imposable. Then, again, if the controller and the box are an integral part, you can dispense with the complexities of making the bus longer. So, no matter how many LEDS, up to about 128 (half of the 256 total), you don't need any more wires.

You would be doing nothing more than sending a serial stream continuously with delays. You'd be using the same bus, but sending the same data to the front and the back almost at the same time. A lamp test function?

Yea, there is stuff to learn about called logic translation and you may need 5V and 3.3 V. I'm after conceptual. Earlier, I brainstormed a user interface with parts pulled out of the air that may or may not exist.

Don;t mind me, I like to think out loud and include everything that I might like given infinite resources and time. When the design starts, it might take little effort to include the secondary parts of the design or you might leave it unpopulated or you might never implement it.

So, the high power version would be similar.
Larger wires for +12 and High current ground. You may or may not want an enable signal. t might be easy to add. It might not. You might incorporate a blown bulb signal. Again, a wait an see.

But the same thing happens. An I2C bus, high power +12, high power ground and some control signals like blown bulb or enable maybe.

You cam back at me and I suggested to measure the current. I'm asked what a dash indicator is. I briefly touched on a user interface and i gave an idea on how this thing might work.

Proof of concept of the "hello world" program is where you start. That "hello world" program might be 4 LEDS going back and forth and then the same program using I2C. Rethink the interface and try to figure out if the process chosen has enough resources.

In order to do the automotive environment right, you do have to pay more attention to managing transients.

 

[Cminke]

wow thats a lot of informstion thank you ill look it over and see what i can make good use off thanks

 

[Cminke]

to add onto this i have found this and im wondering if i could use this if i wired it up? http://www.qrp.pops.net/leds.asp

 

[KeepItSimpleStupid]

That circuit is a simple 555 oscillator driving a decade counter. Decade means 10, so it drives 10 outputs and then starts over again.

It does get your feet wet and the circuit should work on 12 V. It can't drive your high power LEDS as it is, but can be made to.

==

Even though this https://www.psychicorigami.com/2010...ween-spider-eyes-hats-using-picaxe-08m-chips/ is not what you want to do but it's also extremely uncomplicated.

==

In my descriptions, I left a lot of stuff out so hopefully you can see the "bigger picture" and not the details yet.

Parts generally suggested were "sample parts" having the right functionality, but maybe not the right choice.

 

[KeepItSimpleStupid]

Not sure if this topic is over your head yet, or your still researching.

In any event, u thought this might be in order. Simplified/pseudocode.

An 8 bit number is from 0 to 255 and each bit from left to right has a weight of 2^n; e.g. 128 64 32 16 8 4 2 1
ORing is the same as adding. So, to turn on the "1" and the "2" LED, you output 3 to a port.

So a right-left pattern is
128 Index 0
Wait
64
wait
32
Wait
16
wait
8
Wait
4
wait
2
Wait
1
Wait Index 15


So, if this was an array of 8 bit numbers and 8 bits COULD represent the time in say mS (it can't because 255 ms) is too short. Each wait time can be different.

Toy could define the pattern with
Start index
Stop Index
repeat. Repeat 255 might mean repeat forever.

But, anyway thats a simple way of defining a pattern, You could even make it blink.

A different pattern would be further down in the index. It could start at 16 and stop at 100 etc.

Here https://www.google.com/url?sa=t&rct...=NvOw4qlXrscZt2-AxaTCdw&bvm=bv.68911936,d.aWw is a SIMPLE I2C chip that handles 8 bits.

What;s important is the power supply and the source and sink currents. The 3 mA is not enough to drive a simple LED and that's where the ULN2003 or similar chip comes into play.

Instaead of using simple output a value to a port, you have to turn it into a serial stream.