need help with making led sign

Discussion in 'The Projects Forum' started by djsoheil, Dec 4, 2014.

  1. djsoheil

    Thread Starter New Member

    Dec 4, 2014
    11
    0
    hi
    i am very new here
    my job is phone technician
    i design the sign which got 5 12v or 9v led light in it.i can make it up to 10 led
    i need the light to turn on and off one after each other.
    if you guys can help me with the pcb board where to buy one or if you can help me whit design the pcb board it would help me alot.
    thank you
     
  2. ISB123

    Well-Known Member

    May 21, 2014
    1,239
    527
    Schematics?Parallel or series connection?We need more info.
     
  3. djsoheil

    Thread Starter New Member

    Dec 4, 2014
    11
    0
    thank you for your replay.
    they are not Parallel or series connection. there is 5 separate led. i want no1 to turn on then turn of then number 2 led turn on then turn of then number 3 led turn on then turn of then number 4 led turn on then turn of then number 5 led turn on then turn of then they start to do same ting from number 1 to 5.
    i gust i need to design pcb for that?
    i got few ATMEGA328P-PU and ardino to program it
    is any one can help me to design Schematics and pcb for that?
     
    Last edited: Dec 4, 2014
  4. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    2,804
    833
    Designing the PCB board comes after designing the schematic. I take it you are also very new to electronics and need help in figuring out how to wire this up.

    How long will the LED stay lit? How long will it be off before the next LED lights?

    This can be done with a 555 chip running as a clock and a decade counter to light the LEDs.
     
    djsoheil likes this.
  5. djsoheil

    Thread Starter New Member

    Dec 4, 2014
    11
    0
    the led stay on for 1 sec.1 sec before next led lights.
    thank you for your replay
     
  6. ISB123

    Well-Known Member

    May 21, 2014
    1,239
    527
    Should be easy to do with arduino and atmega microcontroller. I'll post some code and schematics in few hours.
     
    djsoheil likes this.
  7. djsoheil

    Thread Starter New Member

    Dec 4, 2014
    11
    0
    that would be awesome
    when i design the pcb board can i send it to you and yo check it out to make sure everything is ok?
    thank you for your help
     
  8. ISB123

    Well-Known Member

    May 21, 2014
    1,239
    527
    Ok
     
  9. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    2,804
    833
    This is a simple circuit, commonly known as a chaser circuit. I tried to draw the schematic, but was missing some components, so I found one online. In fact, there are many references online if you search for "4017 chaser circuit". I modified it slightly for your requirements. It is based on the 4017 chip.
    4017b.gif

    Here is the modified schematic. There was originally more LEDs, but I omitted some because you specified one second off between lights.

    AAC_Chase.png

    In fact, this forum has the same circuit in it's e-books (see links at the top of the page). I provided the link here!

    A microcontroller is also a good solution, but may be more expensive if you use an Arduino; you'll be spending nfor capabilities you don't need, IMHO. The discrete solution will be a couple of USD.
     
    elec_mech likes this.
  10. ISB123

    Well-Known Member

    May 21, 2014
    1,239
    527
    He can program empty atmega mcu with arduino and then use it standalone in the circuit.
     
    djsoheil likes this.
  11. djsoheil

    Thread Starter New Member

    Dec 4, 2014
    11
    0
    thank you i found diy kit with components but that diy kit comes with 1.5v led !!
     
  12. djsoheil

    Thread Starter New Member

    Dec 4, 2014
    11
    0
    i like the idea of atmega
    the reason for that in futer if i change my mind i can reprogram it
     
  13. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    2,804
    833
    Good! Then knowing that requirement, a microprocessor is what you need.

    I do have one more question. When you said
    Did you mean that there is a 1 second period between LEDs lit, during which nothing is lit?
    Or did you want each LED to be lit for one second, then the next for one second, etc..?

    Also, when you said the LEDs in the DIY kit come with a 1.5v LED, you seemed surprised. Most LEDs drop between 1.5 and 3 volts (they are run by current, not voltage). I questioned when you said 9v or 12v LEDs. An LED can run on those higher voltages, with the proper current limiting resistor. Remember, LEDs run on current, not voltage. They DO have a property Vf, or forward voltage, which is what they drop and which is used in calculating the value for a current limiting resistor
     
  14. djsoheil

    Thread Starter New Member

    Dec 4, 2014
    11
    0
    i meant there is a 1 second period between LEDs lit, during which nothing is lit
    i didn't know they run buy current not voltage. i know different between current and voltage but can you please explain to me why i.5v led dose not work with higher voltage is it because in higher voltage you get higher current?
    i don't know the property vf for them led i got.
    but they gone be separately light up and they are not Parallel or series connection in that case dose it matter what is the vf??
    please dont get me wrong if i ask you a question i don't want to challenge you or.... i just like to learn more
     
  15. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    2,804
    833
    Here is a good reference on using LEDs, written by member Bill Marsden. Bill is the local guru in this stuff.

    It matters what is the Vf, because without a current limiting resistor, they will likely burn out. There is a slight chance that the LEDs that you bought has a built-in resistor... Do you have a link to where you bought them?

    In Bill's blog, he describes connecting one LED and provides this diagram:
    [​IMG]

    Note the 330Ω resistor. That is the current limiting resistor. You need to know the Vf to calculate the value for the resistor.
    The supply is 9v and the Vf is 2.5 v. Typical current for a red LED is 20ma. Hence, the resistor is calculated as follows:
    R= \frac{ (V_{cc} -V_{f}) }{I_{led}}

    \frac{ (9_{vdc} -2.5_{vdc}) }{20_{ma}}=325 \Omega

    I suspect that you have built-in resistors, but if you are not sure, they may get damaged.

    Also, you keep saying that they are connected neither series or parallel, but connected individually to your supply. That is a parallel connection, so when and if you look at the blog, you will know what examples apply to you.

    Good luck!
     
  16. djsoheil

    Thread Starter New Member

    Dec 4, 2014
    11
    0
    sorry i don't mean to bother you but i still waiting for the schematics
    thank you
     
  17. ISB123

    Well-Known Member

    May 21, 2014
    1,239
    527
    Not sure if I will be able to do it today because I'm tired.Send me specifications of your LED's and how much LED's are you using?And in which way you want them to light up?
     
  18. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,172
    397
    The 4017 chaser should work, just connect a LED to every other output; good for 5 LEDs. 4017's can be seriesed per Bill Marsden Index.
     
  19. ISB123

    Well-Known Member

    May 21, 2014
    1,239
    527
    You can use 4017 if you want something simple and cheap.Using MCU to control leds is going to be a bit more expensive and complex since its going to need to have a driver which can supply current since MCU shouldn't be used to power anything above 200mA.
     
    Last edited: Dec 4, 2014
  20. djsoheil

    Thread Starter New Member

    Dec 4, 2014
    11
    0
    this is spec i got from the led
    Key Features: LED Light Bulb
    Connectpr Type: G4
    Luminous Flux: 70-90LM
    Output Power: 1W
    Input Voltage: 12V
    Light Color:Warm White Color Temperature: 2800-3200K
    Lifespan: >30000 hour
    Material: Aluminum
    Dimensions: 3.0 x 1.2CM
     
Loading...