Connect with us

my daughter's science project

Discussion in 'General Electronics Discussion' started by kuby, Nov 29, 2011.

Scroll to continue with content
  1. kuby


    Nov 29, 2011
    i am a newby, and wondering if someone could help with this little project.
    this is what she wants to do; the source would be 12 volt dc. from the souce, she wants to have a transmitter and a switch. at the recieving end, she wants to turn on some LEDs. she was hoping to run something like 6 LEDs powered by a small battery (watch battery, or equivelent round flat battery). she wants to press a button (switch) and have the LEDs turn on. let go of the switch and the LEDs go off. the number of LEDs are not that important. She wants to make the LED package small. anybody got any direction on how to do this?

    Attached Files:

  2. donkey


    Feb 26, 2011
    what type of transmission you looking at? infared? or radio wave?
    if radio wave find an old rc car replace the motor with led's and a resistor and that'll work easily enough.
    infared.... well that one is outta my league atm.
  3. davenn

    davenn Moderator

    Sep 5, 2009
    Hi Kuby
    welcome to the forums :)

    You are going to need more than a small watch battery, it would struggle to power a couple of LED's let alone 6 of them and a receiver. One of those small PP3 type 9V batteries would be a start :)

    There are kits in electronics hobby shops that have transmitter and receivers that you could easily arrange to do this sort of thing.
    The transmitter WILL WORK from a small 3 to 6Volt type battery. Use your 9 or 12V battery for the receiver.

    Dont know what country you are in ... but here's an example of what you can use :)

    Last edited: Nov 30, 2011
  4. kuby


    Nov 29, 2011
    thank you for the responses. i like the link that was sent. that seems very interesting and i think that would work. someone mentioned to use a cordless phone. they said i could use the pager (or phone finder). i would just have to the scavage the parts. i do not have any rc cars or parts laying around the house (i got all girls), but i do have a bunch of cordless phones laying around. or would i be better off buying the kit in the above link?
    thanks in advance,
  5. jackorocko


    Apr 4, 2010
    my only issue with the phone pager is that you will need to pretty much keep the phone in one piece. I am sure the paging circuit is built into the phone circuit board. This doesn't make it very small or a pretty solution. But that certainly doesn't mean it won't work. Just build your circuit off the wires that would normally activate the speaker when the paging button has been pressed on the receiver. This will also probably require mains voltage source to power the phones base, transmitter. Something else to consider...

    edit: I just took a look at your diagram, in there you state "12VDC is only power source", that makes a phone impractical. You also said, "no line of sight", that pretty much rules out infrared. With that receiver/transmitter being that cheap, the site dave supplied, it would easily be my choice. You could also fit that into a project box you can buy at radio shack.
    Last edited: Nov 30, 2011
  6. BobK


    Jan 5, 2010
    Except that the transmitter and receiver in the link provided above are for data transmission and would require a microcontroller on either side. They would not be usable as is to do a simple on / off switch.

    The RC car solution is the best bet. You should be able to get a cheap one for on the order of $10 and pulling out and using the circuit boards is easy, at least on the one I once used.

  7. davenn

    davenn Moderator

    Sep 5, 2009
    Yes they are Bob, but not too difficult to add a encoder and decoder
    the chips are around for those too.

    Kuby.... those TX and RX boards I linked to form the main guts of your key fob garage (etc ) door openers. Which would be ideal for your use.
    do a google search of 433MHz RF garage door openers. Remember those fob's have a couple of buttons one to activate opening or in your case turning some device on. And the other button to close the door or in your case to turn that device off.

    all the hard work is done for your :)

    Report back with any othwer queries eg interfacing the door opener receiver to your device etc

Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day