First real project, need some guidance

Discussion in 'The Projects Forum' started by mdelillo, Jan 21, 2014.

  1. mdelillo

    Thread Starter New Member

    Jan 21, 2014
    Hello all,

    This is the first electronics project I've ever done aside from some basic circuits in high school. I've forgotten most of what I've learned, so I'm looking for some help. The goal is to make a circuit consisting of a switch, some LEDs, a buzzer, and possibly a microcontroller. When the switch is flipped, the LEDs will blink and the buzzer will play a specific tune (I assume due to the microcontroller). It should also be on a board no bigger than 2"x2".

    I've spent the last few hours doing research but haven't yet formed a complete picture of what I need to do. I was hoping somebody would be able to point me in the direction of some more resources or give me a general idea of what my circuit should look like.

    I believe I can build the circuit on something like this (maybe a bigger one if necessary):
    I would need a microcontroller like this to controller the buzzer and flashing LEDs:
    In order to program said microcontroller, I would need to make a serial cable like this:
    And the LEDs and buzzer should be easy to pick up from somewhere like RadioShack.

    I guess what I'm looking for is how to tie it all together. What type of power source would I need? The microcontroller wants 4.5-5V, but would that be enough to power multiple LEDs? How do I wire everything together? What types of resistors would I need, and where would they go?

    Thank you very much for your help,
  2. crutschow


    Mar 14, 2008
    I hate to be a wet blanket but if you have to ask what type of resistors you need and where should they go then IMHO you are starting with a more complex circuit than is reasonable for your apparent level of electronics knowledge.:rolleyes: Suggest you start with something simpler (at least something without a microcontroller) and (re)learn a little about basic electronics by reading some tutorials such as here.
  3. sirch2

    Well-Known Member

    Jan 21, 2013
    Don't be put off, there are loads of resources on this board and elsewhere to answer specific questions. You are going to make mistakes (but that's how you learn) so I would recommend not worrying about the size for now and building something on a bread-board, that way it is easy to add and remove things.

    Get the MCU and an LED and start by making it blink - the thing you need to know about LEDs is they need a current limiting resistor in series. But a quick google for driving an LED from a microcontroller will tell you more than you need to know.
  4. elec_mech

    Senior Member

    Nov 12, 2008
    Welcome to AAC.

    crutschow makes a good point, but I can help you if you really want to tackle this in the manner you described. Just understand this is not an entry-level project you're describing, but it's not overly complex either. As long as you're not in a huge hurry, this is doable.

    Depending on the importance of the dimensions given, you could use a recording module to record a tune or play a wav or mp3. This would be a lot less work since you would no longer need a microcontroller. Something like this or this.

    Personally, I love the PICAXE as a beginner's microcontroller. The 08M2 you've selected should work, but we'll need more information first.

    What is this for? Personal project, school, etc.? What is the purpose?

    How many LEDs do you need to light up? Will all be lit at the same time? Will they all remain on once the switch is flipped or do they need to blink or fade on/off?

    What will the colors of the LEDs be? List quantities next to each color. Are you thinking standard 5mm round dome LEDs or something else?

    Do you plan to use a toggle (latching) switch or a momentary one? The former is like a light switch, you flip it on, the light comes on; you flip it off, the light goes off. A momentary switch is like a doorbell, but you can program the microcontroller to turn on the lights with the first press and off with the second press.

    How do you want to power this? Batteries or wall adapter?

    The "tune" will need to be programmed into the microcontroller. This can be challenging. I haven't done this myself, so I can't guarantee success, but I'm willing to give it a shot if you are.
  5. mdelillo

    Thread Starter New Member

    Jan 21, 2014
    Thanks for your replies everyone. Somehow I missed those tutorials, but it looks like that's exactly what I was looking for. This is a personal project just for fun so I'm in no hurry. I'm going to try to read up and figure out how to do it on my own from there, but I'm sure I'll be back with a few questions eventually.
  6. MrChips


    Oct 2, 2009
    Start with simple exercises and take one step at a time.
    Pick any microcontroller development kit and program it to make an LED flash.