Introduction: Minty Beating Valentines Heart

Any woman that thinks the way to a man's heart is through his stomach is aiming just a little too high.

Why not give that loved one something special. A fabulously unrealistic beating heart.

OK. I seem to have a thing for building Rube Goldberg like devices that are overly complicated and do so little. This is one of those.

I'll prob be modifying this as I go, and can already think of things I should be doing different. I will say that the girlfriend actually squealed a little when she saw the completed first version. The cat can't get enough, and will shortly be destroying it I'm sure.

The whole concept is based on general magnetic principals and re-using junk. I have actually used this idea once before to make fluttering mosquito wings. I very well may make another at some point. I'll post if I do...

Parts List:
1 Altoids tin, or suitable container.
1 old or dead CD Rom drive. Desktop style preferred, although a laptop drive would work.
1 555 timer chip.
1 47uf capacitor
1 3906 transistor
2 3.3K resistors
1 1k resistor
1 red LED
Power source - 3-6 volts. This could be a wall-wart, hacked USB cable, AA batteries, whatever.
Wire of various sorts

Soldering iron
wire snips, the finer the better
screw drivers, various sizes. You need at least one large straight tip, and 1 large and 1 small Phillips. The small should be a jewelers size, or so.
possibly a magnifying glass, or reading glasses, depending on your ability to see really small stuff
A good deal of patience

I'm assembling this one "free form" which means that I will not be using a board of any kind. Mostly cause I didn't have any handy. This can certainly be laid out any way you want.

Step 1: CD Rom Tear Down

Without a heart I can never really know what it would be like to love someone, or ever really understand trashy novels. - Tin man, Wizard of Oz

OK. First things first. We need to claim the parts we need from the CD Rom drive. Yes.. I know it's a DVD Rom drive in the pictures. Lets not be picky.... Start taking out screws. After some prying and swearing you should get down to the point where you will see our target, the laser eye assembly at the center. This will become the part that does the actual mechanical "heart beat" work.

Usually, it's a floating assembly riding on two rails. this can vary by manufacturer. If you can get the two rails free, it usually slides right off. Be careful to disconnect the ribbon cables. If you cut them, leave some slack, just in case.

Once you have the main laser assembly free, start removing external parts until you get down to just the laser focusing assembly. This will be where the small Phillips head screwdriver comes in handy. It will be the part with the laser eye suspended between two magnets with some small coils. The coils are energized to move the eye around and provide fine focusing during CD read operations. Check the pictures, it will make more sense.

Be VERY careful to preserve the connections on the focusing assembly. ripping the ribbon cable off the eye makes it nearly impossible to solder the wires to it later.

There are a lot of other goodies inside the remains of the CD Rom drive. take a minute to poke around and see what else you can scavenge. LEDs, motors and such.

Step 2: The 555 Timer Circuit

I always just hoped that, that I'd meet some nice friendly girl, like the look of her, hope the look of me didn't make her physically sick, then pop the question and... um... settle down and be happy. It worked for my parents. Well, apart from the divorce and all that! - Four Weddings and a Funeral

OK, we have our mechanical part. Now we need something to drive it. The 555 is a really nice little workhorse of a chip. We are going to use it to create the pulses that will simulate a heart beat.

The 555 is designed to put out a timed pulse depending on the values of the resistors and capacitor attached to it. I played around a little and eventually decided on a 47uf capacitor, and two 3.3k resistors. This gives a nice beat, slightly faster than a normal human heart.

The diagram below explains how to lay it out. I had to use the 3906 transistor on the output, as the pulse from the chip is just not strong enough.

If the diagram below is Greek to you, I would encourage you to check out these sites. They have some fantastic information to get you started:

You can see that once you have it together, it looks easier than it appears. These are the basic steps I use:

1. Connect Pins 4 and 8. If you are free forming this, you can bend the pins under the body.
2. Connect pins 6 and 2. I usualy run a jumper over the top of the chip to avoid bending the legs off.
3. Solder the capacitor across pins 1 and 2, with the negative side on pin 1.
4. Solder one of the 3.3k resistors across pins 7 and 8
5. Solder the other 3.3k resistor across pins 6 and 7.
6. solder the negative power lead to pin 1
7. solder the positive lead to pin 8.

I would apply power at this point and check to make sure I am getting a pulse by putting an LED across pins 3 and 1, with the positive lead on pin 3. If the chip heats up at all, something is connected wrong. If you have a nice pulse, then: (with the 3906 in "dead bug" mode, flat side up, pins facing you)

8. solder the middle leg of the 3906 to pin 3.
9. Solder the left leg to ground (pin 1)

Now, you need to connect the "eye" to the circuit. There will be 4-6 connections on the eye. take a battery or power supply and test the contacts to see which ones make the coil jump up. some contacts will make is slide to the side, some up, some down. you will get the idea. When you have the right ones...

10. solder the right leg to one of the connections on the coil from the CD Rom drive
11. Solder a connection from the other connection on the coil to the + source (pin 8 or 4)

I find it's not generally needed to solder pin 5 of the 555 to anything. it just works.

Now, when you connect the power, you should see the "eye" jump up and down. If not, check your connections. The biggest mistake I usually make is connecting the 3906 backwards.

Step 3: Doctor, the Paitent Has a Pulse...

Q: What do you do when a pig has a heart attack?
A: You call an hambulance!

We are in the hone stretch now. We have a working timer, and a working "thumper" for our heart. I took the working assembly and glued it to the inside of a Altoids tin. I then glued a small coil of wire on the top of the eye, making sure it would not hit the top of the tin when the eye extended.

At the last minute, I added a red LED to the circuit. I just connected it and the resistor to the positive and negative power-in. nothing fancy. Just as shown.

I drilled a small hole in the top of the tin directly over where the eye is. when the tin is closed, I drop a piece of wire through, when the eye jumps, it will push this wire (or "push rod")up and down.

I then made a small loop in the top of push rod so I can glue it to one end of the heart. I closed the cover, and cut a heart from paper. I glued the bottom tip of the heart to the top of the tin, then glued the loop on the wire to the top of the heart. Look at the pictures. you will get the idea.

I would post video.. but I can't find the charger for my camera. maybe at some point...

That's it.. Have fun. As usual, there will be a torrent of people who have more ideas. Bring it on! and lets see the pictures when your done.


cybertron made it!(author)2012-02-17


In your schmatic and instructions you state using a 3906 transistor.
your smybol for a 3906 transistor is wrong.A 3906 is a PNP transistor.
you have a smybol for a NPN transistor which is a 3904 transistor.
which transistor are you using a npn 3904 or a pnp 3906 transistor.
the circuit may need a resistor on the base of the transistor to lower
the base current.

sarebear made it!(author)2007-02-11

I'm going to sound like a space cadet, but I'm not very mechanically savvy... where can I find all of these parts? (555 timer chip, 47uf capacitor, etc...) I'm clueless but I want to try this :)

photozz made it!(author)2007-02-11

the capacitors, resistors and timer chip are all available at most Radio Shack stores. they also sell board you can use to solder this all down instead of free forming it the way I did. Good Luck!

rajeevmahesh made it!(author)2011-09-13

plz send me the teardown report of lg cd rom 52x max

J_SCAP made it!(author)2007-09-22

"Any woman that thinks the way to a man's heart is through his stomach is aiming just a little too high." uhhhhh you know little kids could be seeing that and ask there mommyz and daddys and they would kick them off the cpu forever untill they go to colage

mg0930mg made it!(author)2008-10-05

Excuse me, but can I ask what you are saying. I can't read that. What is 'colage' and 'mommyz' or 'cpu'. Please spell correctly.

arzarach made it!(author)2009-12-18

ur deffinitly not a teenger cuz yude be able 2 read wht she wrote.  colage = college          cpu = computer

mg0930mg made it!(author)2009-12-19

Do you really need to be so obnoxious?

arzarach made it!(author)2009-12-20

im not bein obnox. you asked wht she wrot so i explained it

mg0930mg made it!(author)2009-12-20

I've read your other comments and can clearly see they're not spelled like these one. Your obviously doing it on  purpose and therefore being obnoxious.

g3thig4chri5 made it!(author)2009-12-26

"8 year olds Dude"

arzarach made it!(author)2009-12-26

not really dumba@#$  im 14

g3thig4chri5 made it!(author)2010-05-26

Fooled me

mg0930mg made it!(author)2009-12-26


luke made it!(author)2008-11-18

A Central Processing Unit (CPU) is a machine that can execute computer programs.

srmousse made it!(author)2007-02-18

photozz, Loved the idea... I found a perfect heart shaped tin to build it in... stayed up till 4am trying to get it to work...I followed your instructions to a T, twice that night and both times when i went to test it after step 7 the thing started getting very hot... the led will light up but not blink. I figured maybe I was just too tired.. So I tried it again this afternoon.. same result... any thoughts? I appreciate the help!

photozz made it!(author)2007-02-18

Yep, figured it out for you, I think. Ill be the first to say "my bad". The diagram was correct, but the text had the positive and negative leads reversed. the positive goes to pin 8, the negative to pin one. My sincere apologies.

photozz made it!(author)2007-02-18

Oh, and I fixed the text in the instructable. it should be right now.

lemonie made it!(author)2007-02-10

Could you not use a small audio-speaker? Cheap headphones are going to be a lot easier to obtain & sacrifice than an optical-drive.

photozz made it!(author)2007-02-10

yes, you could use a small speaker. This is just nice as you get a relatively great deal of movement out of a very small part.

lemonie made it!(author)2007-02-11

You're getting a good 'rap' from the lens hitting the tin I guess?

photozz made it!(author)2007-02-11

it's mounted low enough that it's not hitting the tin. you could move it up .. lot's of ideas you can do here.

Kiteman made it!(author)2007-02-10

Outstanding Instructable! When I eventually get around to this (boy, is this website giving me a long to-do list!), I think I'd use a more decorative box, and a shiny heart (mylar foil?). My wife has a thing about dragonflies, so maybe I'd make a dragonfly with shiny mylar wings in place of the heart. Actually, I think I have a dead CD player somewhere, they have a similar "eye", don't they? (wanders off to furtle through project box...)

photozz made it!(author)2007-02-10

any "optical" drive will work fine. Good luck, and I want to see the results!

lemonie made it!(author)2007-02-10

Sorry, I overlooked the obvious. You say "Here you are dear, you always said I spent too much time on the PC, well I've sacrificed my DVD drive to make this for you. And if that isn't love, I don't know what is." ("You never liked that drive though. You're going to buy a new one aren't you?"...)

jeffreyf made it!(author)2007-02-09

Oh my. Someone get Mr. Poe on the phone, stat.

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