Step 5: Choose LED or Buzzer

  • This is another SPDT switch.  
  • Each side will have a sensor.  The left will be a LED and the right a buzzer.
  • This is constructed much like the last step.
  • Place a brad on ether side of the paperclip switch.
  • Poke a larger hole for the LED above the left brad and from the bottom stick the lens in the cardboard.
  • The LED needs to be installed the right way.  The positive lead/wire is longer than the negative wire.  Now wrap the positive lead around the brad leg below it and the negative lead gets wrapped around the brad leg above it.  (see pic)
  • The other side of the switch has the same thing happen, but with the buzzer.  Poke 1 hole near the right side switch brad and pull both wires from the buzzer through it.  You may need to strip a bit more off the wire ends.  Wrap the red wire end around that "switch" brad and the black wire can go around any brad that is beyond the LED.  (see pic)
  • Use a bit of tape folded over to stick the buzzer to the board.  
  • It should look something like the pictures.
<p>Its awesome Matt. :) Thanks. I never knew that the battery can conduct electricity through paperclips. :) this is for my science fair project. I'm in 5th grade. what do u think ill get? on a scal from 1 to 10</p>
Thanks! This will be my son's introduction to electronics. He is 5 years old.
<p>Where do you buy all the supplies?</p>
<p>yea WHERE?</p>
<p>Mostly on-line but sometimes Radioshack. </p>
<p>That is fantastic!!! Tell him I said great job!</p>
<p>what kind of paperclips do u have?<br></p>
<p>The paperclips couldn't make the LED light, light light up</p>
<p>awesome </p>
Brilliant! I just read it... If we all did this instead of breadboards, a lot of money would be saved! Thanks!!! I also love ur iPod charger... Ive built it!
<p>That is great. Thanks!</p>
<p>Nice sensor! We are going to make this sensor using soldering, but we are wondering if the paperclips or the metal brads works as resistors? </p>
<p>I don't think the paperclips or brads resist much electricity. They are more like wires.</p>
<p>Where do you buy the supplies?</p>
<p>Amazing! So nice that you are sharing some tips for others to replicate your project! How long did it take to complete this project? Thanks!</p>
This is pretty cool. I haven't actually ever used a LDR.
<p>My buzzer will not sound when I switch the circuit through the light dependent resistor (LDR). I can barely see my light dimmed through the LDR. I have tried connecting extra batteries in series. Obviously shining a light on the LDR brightens the LED, but nothing seems to help the buzzer. Any ideas?</p>
<p>This is brilliant. I'm new at this and as i dont have all the tools, it saved me. Thanks mate.</p>
I tried this and I am having a problem getting anything to work. I went to staples to buy paper clips and the brads and I am wondering if these paper clips have some type of coating prohibiting the flow. &nbsp;Has anyone run into this problem?
I have run into the same problem and it was the brads that where coated with a clear non conductive material. had to sand them
I didn't run into the problem, but you certainly cannot use the colored plastic coated paperclips. The old fashioned bare metal ones are conductive...the plastic will just insulate the metal....<br><br>Good project BTW!!!!
I have been away, thanks for your input. I would just add that if you have a voltmeter you can check for small shorts (gaps in the circuit) you may have not have seen. Thanks
Love It
This is cool, what a good idea!
Thank You
You are Genious <br>I Love It From Bottem Of My Heart
Hi, <br> <br>If you don't mind me asking, could you think of an electronic i could possible &quot;harvest&quot; an LDR from? Because I live in Canada and i unfortunately don't have the novelty of Radio Shack :/ <br> <br>- Bryan
Hi, Matt:<br><br>How are you? Great I hope.<br><br>What are the minimum and maximum required specifications for the following components,<br>That, will work with the 3 volt - Button Cell Battery:<br><br>(1) White or Blue LED,<br>(2) Piezoelectric Buzzer, <br>(3) LDR (Light Dependent Resistor)<br><br>Thank You, for your assistance regarding this question.<br><br>Take Care,<br><br>Wilfred Wheeler
i'm well thanks,<br>I am not sure if understand your question but with 3 volts a white or blue LED will work but only one. The buzzer will work but not at the same time as the LED and any LDR can be used as you wish. Feel free to ask again if you have questions.<br>Matt
its very simple to understand and cool idea!
Great idea for breadboarding simple circuits! I would substitute a LED with a blinker. Another possible enchancement is to hook up a music chip and a piezo disk instead of a buzzer. I vote!
Thank you and good ideas.
its too gooood!
This is a great idea for teaching scouts electronics for the activity badge.<br>
This would go perfect with <a href="http://www.instructables.com/id/How-to-make-conductive-play-dough/" rel="nofollow">my conductive play dough</a>&nbsp;instructable&nbsp;for teaching circuits!
I love this project and admire the simplicity of how taking something as complex as electronic circuitry and simplifying it so that anyone can understand it. I remember having something like this in my 3rd grade science class and was absolutely loved it. <br><br>Thanks for the nostalgia!
Really like how simple this is. You've got my vote. : )
This is a really nice project! I remember doing something like it when I was young.
Thanks, me too. In 7th grade I think.
to make the led go brighter in shadows i would need to connect it in reverse yes?
The LDR would do the same ether way you connect it. To make it go brighter in shadows would be a different circuit and i don't know it off the top of my head.
No. That would cause some serious issues.
Hi. Nice instructable. I really will try something like this.. But i want to ask you something. If i want to use more Leds to make a heart or something like that and i need more volt (a mayor number of bateries or a bigger batery) how do i know the limits of volts to be safe? i mean if i put a AA batery or 2 can it be safe to be manipulate the Paperclips or Metal Brads with hands? <br><br>Thanks and sorry but i dont know much about electricity and circuits but i want to make some cardboards love cards with your idea. <br><br>Thanks Again. <br><br>S.
Usually it will be safe unless you're working with high voltages (at which point paperclips and batteries shouldn't be involved)<br><br>an AA battery is 1,5 volts so he actually used 2 of those for this project. You can go higher without problems. (although I'd say don't go over 4 as it's not needed for any project for testing like this)<br><br>Instead, you can also hook up the LEDs next to eachother (parallel) in stead of behind eachother (series) meaning that you won't need more voltage then with only 1 LED
Thanks Ganoderma, I was about to say the same thing. Thanks S. I'm glad you liked it.
Very nice indeed! Thank you!
Glad you liked it.
Thank you! - This is fantastic. I am a noob to anything electrical, but this reads very well and I already understand more than what I have tried to learn from several other sources.<br><br>Great Job. you got my vote :D

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Bio: I'm a youth pastor in Minnesota. I went to Cornerstone University and studied Bible, Youth Ministry, and Psychology. I'm a Maker hobbyist for ... More »
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