Completely new at this

Discussion in 'The Projects Forum' started by 32_d3gr33s, Oct 30, 2011.

  1. 32_d3gr33s

    Thread Starter Member

    Oct 29, 2011
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    I'm interested in making a lightbar and or traffic advisor in about 1:10 scale for some Rc cars. Problem is, I have no experience in anything of this nature. I actually have a lightbar that I purchased online, but want to see if there is a cheaper solution for making multiple more of them because I have 4 Rc cars and my buddy has a few as well.

    For the lightbar I have this, and want to make something similar. It doesn't need this many patterns but the more it has the better.
    http://www.youtube.com/watch?v=APWo7tweUYc&feature=youtube_gdata_player

    I also would like to be able to make something similar to this...
    http://www.youtube.com/watch?v=-_yhwi3skbY&feature=youtube_gdata_player

    Basically I want both about 3-4 inches wide. Not sure what led's to use so make any necessary suggestions. I'm assuming I will probably have to program a chip or something for the flash patterns so please explain or link how to do that. The lights don't nessisarily have to be on the circuit board, because I will more than likely make a custom housing for the LEDs

    Any help would be awesome as I'm trying to get these done before Christmas.
     
  2. tracecom

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    Apr 16, 2010
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    The project is doable, but has a fair degree of complexity for an electronics beginner. The LED's will have to be controlled by a micro controller, which will have to be programmed to achieve the various flash patterns. (And the flash patterns will first have to be defined.) The programming will differ depending upon which micro controller you use, and may require some specialized hardware and software to program the μC. The PICAXE family of μC's are programmed using free software and a PC, although you do have to have a special programming cable (either serial or USB). The first video you linked to is using surface mount components, which require either specialized soldering equipment or very good hand soldering skills. You say that the LED's don't have to be mounted on the PCB, so that means a fairly complex wiring harness will have to be fabricated; the harness will need at least one wire per LED plus a common wire, so it could get bulky and hard to manage. A PCB is a better choice, and can be designed and fabricated, but requires yet another set of specialized skills.

    Designing these, procuring parts, and building them from scratch in less than two months would be somewhat of a challenge for someone who already had the requisite skills. I hate to rain on your project, but IMHO you would be better off buying the kits.

    But maybe someone else on the forum will have better ideas than mine. Good luck.
     
    Chris15 likes this.
  3. Wendy

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    Mar 24, 2008
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    I tend to agree with the above assessment. Simple patterns, without choices, can be done with simple circuits, and you can make the basic light bar (minus the µC) fairly easily, though the LEDs are fairly specialized and will take time to get in (several days or more).

    So, to me, it boils down to the control electronics, it is worth learning in it's own right, but it is a very steep learning curve.
     
  4. 32_d3gr33s

    Thread Starter Member

    Oct 29, 2011
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    Well, i guess they really dont have to be done by Christmas time, but thats what i was hoping for. This kind of stuff always interested me, but i never knew where to get a start and i just stumbled across these boards a couple days ago. I really would like to figure out how to make some of these.

    I guess if some one could point me in the direction of how to learn how to make a pcb and an approx cost of materials needed to do it, and also how to program a micro controller and the approx cost of that. I can then decide if its even worth it to build a few of these boards.

    I did come across a cool/cheap idea after i posted this thread though.
    http://www.youtube.com/watch?v=lTnFXm_2JHE
    would anyone be able to tell me how to make something such as that? That seems like it would be a little cheaper/easier to do...
     
  5. elec_mech

    Senior Member

    Nov 12, 2008
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    Tracecom put it very well and Bill brings up a good point. If you can get away with using just one light pattern, you can do this with discrete logic (no microcontrollers). This is far more old school in terms of police flashers, but I thought it might interest you:

    http://hackaday.com/2011/10/23/toy-car-fitted-with-lights-and-sirens-is-a-childrens-delight/

    You can make it smaller with less LEDs or smaller ones.

    There is always the popular Knight Rider effect which is doable with discrete logic, but again you'd be stuck with just the one pattern. Looking at your last post, it appears the LED bars are using a Knight Rider affect with two or more different rates and a pause. I think this is doable with discrete logic alone, but it would require several ICs.

    If you decide to proceed with a microcontroller, I'd suggest putting the LEDs on a small PCB with an LED controller IC that uses I2C or SPI, reducing your wire count to 4-6 wires from that board to your master board holding the microcontroller and any other parts. If you're going to need it as small as possible, you'll need SMT parts which means you'll need to make a custom board adding more time to your project.

    If you have 1-2 hours a day on weeknights and the better part of your weekends free to work on this for the next two months, you can probably get one done. Once you've figured out how to make one that fits, looks, and works the way you want it, you'll have the ground work to make more quickly, but I'm not sure if you'll have time to make one from scratch, perfect it, then build more in two months. However, if you have the time, we're here to help . . .

    If you plan to proceed down this path using a microcontroller, make a simple drawing of the total number of LEDs you want to use, label them LED1 - LEDx, and list out all the patterns you want them to light in. From there, we can help you pick a microcontroller (I agree with Tracecom, if you haven't touched a microcontroller before, PICAXE is probably the easiest and least expensive to get started on), help you determine what other parts you'll need, etc. Also, tell us the maximum dimensions you can use for the LED bar (length, width, height) so we can help gage whether this can be done on one board or multiple. This also helps us determine which parts might be a better choice to avoid tons of wiring.

    Good luck!
     
  6. 32_d3gr33s

    Thread Starter Member

    Oct 29, 2011
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    Alright... Possibly simpler idea (maybe)
    #1 flashes 3 times, then #2 flashes 3 times, continuously.
    At the same time, #3 flashes once, then #4 flashes once, continuously.
    Would this be do-able in a shorter time frame with less money involved?? I'm not dead set on the patterns, so of something won't work I'm open to suggestions. I'm looking to make this 4-5 inches wide.
    [​IMG]
     
  7. Wendy

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    Mar 24, 2008
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  8. 32_d3gr33s

    Thread Starter Member

    Oct 29, 2011
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    I tried reading through this one, but I'm just completely lost with it. I guess I have no idea what all the terminology means, and looking at the pictures is like reading Chinese for me. Anything that explains things for a beginner?
     
  9. Wendy

    Moderator

    Mar 24, 2008
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    The way to handle this is to ask specific questions. There is a language associated with electronics, and it starts with schematics. A schematic leaves very little ambiguity. The arrow on most components point to the negative power supply buss.

    Use the copy/paste feature in Windows (or whatever) to post the sections you have problems understanding.
     
  10. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    Yes, that's much simpler. I don't have time to comment further on it right now, but I'll be back in a couple of hours.
     
  11. 32_d3gr33s

    Thread Starter Member

    Oct 29, 2011
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    Alright. That's great! I really don't need a ton of flash patterns, considering the lightbar I have now I usually leave it on 1 pattern all the time.
     
  12. elec_mech

    Senior Member

    Nov 12, 2008
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    I'll look at it tonight and see what I can suggest.

    You can do with discrete logic (no uC) if you'd like. The plus side is there is no time lost to learning to program. The down side is your circuit will require more parts and assembly time and probably cost more. If you don't have room for a larger circuit board with the lights, it can certainly be moved. Cost-wise, it shouldn't be a ton more than using a uC, especially factoring in buying programming gear to get you up and running. If you were planning to mass-produce these, then an uC is the way to go, but for a handful, discrete logic is great, plus you'll learn more on the electronics side which I recommend before jumping into programming anyway.

    Okay, 4-5 inches long is helpful. How deep or wide? 1/2", 3/4", 1", etc.? I'm trying to determine if you need the lights and light bar as small and "tight" as the first video you posted or had something else in mind? Rectangular LEDs could work really well (save you a lot of "making it pretty" time), but they might be too big or dim for this application.
     
  13. 32_d3gr33s

    Thread Starter Member

    Oct 29, 2011
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    I would like to have the lightbar pretty close in shape as the first video I posted. So about 4 or 5 wide and and an inch or so deep. I'm really not picky as how its set up though, just what ever is the easiest to do for a beginner. Would everything be on a single board and it would be used as the base of the lightbar, (like in the first video) or would it be something separate and I would just have the lights connected via wires?
     
  14. tracecom

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    Can you measure the PCB you have and post the length and width? Also include the location of the four mounting holes and the LED's; a dimensioned drawing shouldn't be too difficult. I think that whether you use a μC or individual IC's, it will all go on the PCB (except the battery, of course). However, it will likely be a bit thicker because of the non-surface mount components.

    ETA: I just noticed that you have 20 LED's rather than 16 as in the video. That's not a problem, but is that what you really want?
     
    Last edited: Oct 30, 2011
  15. 32_d3gr33s

    Thread Starter Member

    Oct 29, 2011
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    I'm not sure if I can get the measurements from the one I have. It's all assembled and im not sure if I can take it apart. I'll check when I get home from work in a couple hours. As for the mounting locations I think they are about an inch in from either end. I'm not too picky as to where they go, because I will just be drilling holes in the top of the body to attach them. I'm not set on having 20 LEDs, it just seemed to go better for the pattern I had in mind
     
  16. tracecom

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    Don't take it apart; just measure as best you can from the assembly.
     
  17. 32_d3gr33s

    Thread Starter Member

    Oct 29, 2011
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    For simplicity sake, would it be easier just to do 4 red / 4 blue in both front and back and have them alternate flashing 3 times, (basically what my design is, with the white taken out, the 2 middle yellow removed, and the other yellows into red/blue). Im wondering if it would be easier to start that way, and then maybe trying this pattern with my next one?

    I'll try to get the measurements when I get home. But that will be about 3 hours
     
  18. tracecom

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    Let's try the four colors first; I think it will work fine.
     
  19. 32_d3gr33s

    Thread Starter Member

    Oct 29, 2011
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    not sure if you wanted spacing of the leds or not...
    this is just the size of the board
    [​IMG]
    the leds look to be about 1/2" apart
     
  20. tracecom

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    Good...thanks.
     
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