Introduction: Beating LED Heart Picture Frame

For valentines day I decided to make my valentine a picture frame that slowly pulses on and off (like a heart beat) when it is picked up. You can use the same tequnices to make a pulsing light effect on other projects like a computer case mod. Swap out the heart shaped frame for the shape of your choice and the red LEDs for your favorite color.

The frame is made with two small pieces of plexiglass. and the finished frame is no bigger than 5.5" but could be made to any size. LEDs inside light the bottom larger layer of plexiglass. The light will catch on anything that gets in its way between the LEDs and the edge of the plexi. I etched a message in the border which then becomes easily visible when the frame is lit.

The circuit I hacked together from some other more complicated designs is enterally analog and requires no voltage regulation. This means that the circuit should last a long time on a single 9v battery because the 555 timer chip is running directly off of the 9v battery and can continue to use the 9v as a power source as it falls well below the the 9v value. It should continue to work all the way down to ~4v as the 555 only needs 3.3v minimum and the led's only need ~1.4v . A micro switch underneeth turns off the pulsing effect when not in use and the frame is only turned on when picked lifted off of the surface it is resting on. This means it further saves power by only operating when someone is holding it and looking at it. Other modifications could easily be added to make it light sensitive or moation activated as well.

All of the electronic parts necessary should be available at your local electronics store as well and only basic soldering skills are needed to assemble it.

Step 1: What You Need...

You will need only a minimum amount of tools and materials to create this project. I used 1/8" plexiglass I believe that I had in my garage. Beyond that you will need a picture, photoshop is good to use because you can easily scale and play with the layers. You will also need a project box, a 555 timer, a 100uF capacitor, a 100 ohm resistor, a 500 ohm resistor, a 9v battery, and a few small other parts like a switch and proto board to put everything on.

The key to the circuit is using a 555 timer to create a slowly fading in and fading out pulsing effect wile not going completely dark. I have tried many different pulsing circuits until I found one I liked. I then modified it until it had the fewest parts possiable. You could make it without the pcb if you wanted and just solder the parts together. (pcb posted soon)

Step 2: Make the Frame

First go make your basic template in photoshop. I found some heart brushes online and found a picture to fit. I then used the transform tool to create two different sized hearts. I printed some test pages until I found a size I was happy with. The larger heart is 5.5" I decided to go with a stylized heart and cut off the tip at the bottom so that it would stand up well.

Step 3: Cut Out Frame

I used a nice bench grinder because I found a friend who could lend me his. If you dont have one you could use a dremel as I was planning on doing. It just goes much easier with the right tools. You could even get the whole thing laser cut if you wanted. But where is the fun in that? I used my printed out templates and taped them to the front of the plexiglass. I then used a sharp exacto knife to trace out the heart shape onto the plexi. This created a guide line for me to follow when I was grinding. I also cut a circle out of the middle of the larger heart for the LEDs to go.

Step 4: Etch Frame

Now it was time to etch the larger heart so that it would show the text. This is where the laser cutter/engraver would have come in handy. I had a dremel with an engraving bit and it did a decent job. I would recomend trying your skills on a practice piece. Go slow and take your time. You can always remove more material you cant put it back on!

Lets first talk about how I made the template. I took my same photoshop file and wanted text to wrap around the curvy heart shape. This is very simple once you know how to do it. Use the pen tool and draw one side at a time from the middle top to middle bottom on separate layers. Dont worry if you have shaky hands or you mess up you can use the other pen tools to fix your curves and straiten everything out. Once you have your two curves drawn click on the Text tool and hover over one of the lines. You will see the icon change to having a line drawn through it. When you click you will now be able to type text on that path you just drew. Play with font sizes and styles to get everything the way you want it. Unless you are awesome with a dremel then I would suggest that you use as large and simple of a font as you can because many of the smaller details will not show up well.

Once you are happy with how the image looks flip it horizontally then print it out. I printed mine onto sticker paper but you can use regular paper and some scotch tape if you want. Sticker paper is very useful for projects like this so it is worth a few bucks to have some on hand. In the second image you can see the sticker paper stuck to the back side of the plexiglass with the picture taken with the camera flashing from behind to illuminate it. The reason for the flipping of the image is so that we can etch on the back side where imperfections will not show as much and the front side will look glossy and smooth.

The final image shows after the etching with the heart being edge lit by my flash for purposes of taking the picture.

Step 5: Finish Picture

Now that most of the hard work is done it is time to finish up the picture so that we can snap it into place when the rest of the frame is done. I picked up this ~$3 notebook from a local drug store because it had a thin red semi transparent cover on it. If you have an old notebook you can use that as well. This will make up the backing for the picture so that it looks nice from behind and the sides.

Take your smaller heart and use it as a template to cut out the right shape using a sharp exacto blade. I cant stress enough how helpful it is to use new exacto blades for this kind of thing. Once it is cut out you can trim the edges or any imperfections by running the exacto blade along the edge of the plexiglass until both pieces are identical. You may also note that I drilled holes in the smaller heart. This is to join the two hearts together later with some small bolts and nuts. Make sure to cut holes in the plastic to match.

I thought the red plastic would be enough to keep a red ring of LEDs from leaking through the picture but it was not. I then concluded that tinfoil placed between the picture and red plastic would block all light for sure as well as not short out the LEDs. I used 3M #77 spray glue (another favorite product of mine) to glue the three pieces together. In the last picture you can see all three assembeled with the small bolts inserted. Use the exacto knife where needed to trim everything up. I used windex to remove all fingerprints etc from the plexi.

Step 6: LEDs

I picked up some red LEDs at my local electronic shop. These turned out to be pretty dim compared to other LEDs I have worked with. For a project like this it is worth hopping on ebay and picking up 50+ super bright LEDs for ~10$ or less. It takes about a week to ship from Hong Kong but you can get lots of super bright LEDs with resistors and free shipping for MUCH less than at Radio Shack etc.

I took my borrowed grinder and ground my LEDs flat on two sides as you can see in this picture until they were the same thickness as the plexiglass. Simply hold an LED by the legs and apply light pressure against the grinding wheel and you will be done in no time. Remember to go slow. The LEDs are really just a diode thats covered in a hard plastic lens. You can grind it down or sand it to give LEDs a diffused look. In this case the sides are diffused but the tip still has the lens quality and throws quite an intense beam of pure red light. (the LEDs in this picture are the old ones.... the nice LEDs did not arrive from Hong Kong until the day before valentines day! I rebuilt it with them when they arrived)

I then used the hole I had cut in the larger heart and some tape to create a jig of sorts. I first soldered two LEDs at a time together by the negative (shorter) legs and bent the (longer) positive legs up at about 45deg. I taped 4 pairs of LEDs at equal 45 degree angles from each other and then soldered the now touching negative legs together. Then I bent down the positive leads so they were all touching. I took some cat5 networking wire to use for a lead. The negative (blue) is connected to all the negative LEDs. The positive wire is wrapped around all of the positive leads binding them together then soldered.

The end result can be seen in the video before the etching was added. The LEDS are flush with both sides of the plexiglass until somewhere near the middle where the curving upward of the positive legs begin to stick out. Thats ok though because we only need one side to be flush.

I took a small project box and trimmed the corners to fit the shape of the heart so that it would not show near the bottom. I used hot glue to attach it to the larger heart. Note I attached the BOTTOM of the box to the heart so that I could later have access to the screws that hold the lid on the back. After attaching I cut a hole gradually until the LED assembly that I soldered together fit in nice and flush. I then used a small blob of hot glue next to each led to hold it in place.

Step 7: Build the Circuit.

I will include the schematic again in this step for reference but once you have the parts it should take all of 5 minutes to put this together on a bread board. The beauty of this circuit is that it is all analog (meaning no code or processor to fail or program) and it requires a very minimum number of parts you should be able to find at radio shack or a local electronics store. Let me take a minute to explain the circuit.

The 555 timer circuit is one of the best known IC's around. Apply voltage and it will produce a pulse which you can then use to do all kinds of things like build a clock etc. In this case I wanted to build a circuit that would slowly increase voltage to an LED then slowly decrease voltage again. The way to do this is to start with basic PWM. Pulse Width Modulation can be found all over online and here on instructables. Basically instead of changing the power sent to the LED I am sending it manny quick pulses of power every second. The more pulses I send per second the more power the LED receives. The fewer pulses I send the dimmer it becomes. We see this as bright and dim but in reality the LED is flashing on and off much quicker than our eyes can detect.

The 100k resistor and 100uF capacitor are the main components which control the rate of fading in and out. The capacitor serves as a reservoir so that when the power is cut to the led it slowly fades out instead of a quick flash on and off. The resistor controls how fast the circuit is powered up again and therefore controls how fast it fades on. I have built this exact circuit three different times with separate components and used variable resistors and different capacitors and many extra unnecessary parts. This circuit will produce the exact effect shown in the videos and should cost less than $5 for all the parts needed.

The Transistor (2N2222) is the smaller TO-92 package size. This acts as an amplifier/switch to control the LEDs. You cant connect the LEDs directly to the output of the 555 timer (pin 7) because the signal is too weak to power them. The transistor acts as both an amplifier and an electronic switch. It connects to the power source with the Collector leg, the output with the Base leg, and the LEDs with the Emitter leg. Whenever it receives a signal on the Base leg (from the output of the 555 timer) it applies power from the 9v power source directly to the LEDs through the 500ohm resistor. Wont this fry my LEDs though? It would if you connected them directly to the battery. Since we have built a PWM circuit they are all receiving 9v for a very short amount of time. So short in fact that measuring the voltage with a volt meter shows 1.3-1.6v which is perfect for almost all LEDs.

I connected all of my LEDs in parallel meaning that all of the positive leads are connected and all of the negative leads are connected. If one were to burn out the others would keep going. Also I only need one resistor for all of them and it makes soldering them together much easier.

I used a small piece of prototyping board that was ~1$ and cut it to fit in the box. You could solder everything together if you wanted or make a PCB but this worked well for me. I used double sided sticky foam tape to tape the circuit board inside the project box. The wires from the LED array (green/white) are soldered directly into the board. The negitive 9v battery connector is also connected directly to the board. The positive lead however is connected through a switch on its way to the board.

You can use any kind of switch you want to turn on and off the LEDs. You can use a simple toggle switch on the back side to switch it on and off, or a mercury tilt switch to turn it on when you stand up and off when you lay it down. I chose to use a small micro switch with a metal lever arm. In this way when the heart frame is picked up it will begin to pulse and when it is set down it will turn off. The switch has three connectors on it. Figure out which ones you would like to use and test it before gluing it into place. I used hot glue here as well. The metal leg sticks out just enough to trigger the switch when it is standing up. The weight of the 9v battery helps this as well.

Step 8: Finished

After some testing and tucking the wires into place you should be about finished up. Not shown in the pictures are the opposite side of the bolts used to hold everything together. They go through both pieces of plexiglass and the project box. Inside each has a small nut holding everything together. On the back side you can see the red plastic notebook showing and the messier side of the etching. On the side you can see the micro switch being pressed on. The LEDs look great in person during the day and amazing at night. Because of the simple design of the circuit and awesomeness of the 555 IC this circuit should run on a 9v battery until it is completely dead since it uses no voltage regulator. Simply unscrewing two screws on the back allows for a quick swap of the battery if needed. I hope you all enjoyed this instructable, I know my valentine did.


rubendlove. made it!(author)2015-06-15

this diagram is wrong, its missing a jumper between pin 8 and 4, and the resistors are wrong. and the cap it's 1000mf or more one the resistors should be 470ohms

and the other variable. .

JorgeTristan made it!(author)2013-11-17

Hi, following your schematic only leads to fade in LEDs (when power just plugged in) but no fade out; once lit, the LEDs will just stay on, I've replaced the 555 two times, thinking that it could be the reason why. Instead of a 100k resistor I'm using a 100K Potentiometer and a TIP31 NPN transistor, instead of the 4 LEDs I'm using a strip of LEDs and a 12v Wall adaptor, nothing heats, so nothing is burnt. cheers!
Nice project BTW :)

pcmofo made it!(author)2013-11-18

I have seen more than a few people have similar problems following my exact design. It would appear that the setup is extremely sensitive to the exact components used. You may have to experiment with different values for resistors and capacitors to get the exact same effect.

McQAC made it!(author)2013-07-11

So this is pretty sick. I'm a novice to the umpteenth degree. How would I add a 4026 counter to randomize the lights?

Prestond made it!(author)2010-06-12

i can't get my leds to fade out :/

luma024 made it!(author)2011-12-11

This circuit is a bit unstable ,, at least the way I built it ,,, lowering the 100k resister was the only way I could get it to run reliably ... :)

luma024 made it!(author)2011-12-11

try lowering the 100k resister to 90k or even less, this worked for me....
Hope it helps someone..

Prestond made it!(author)2010-05-11

my leds refuse to fade and it is driving me... more into insanity
I'm using an LM555 timer and a 2n2222a transistor
what could possibly be wrong?
I've reworked the circuit, stared at the schematic for... a half hour and i have yet to reach a conclusion on anything i could have done wrong, so i'm thinking my parts might be.

Prestond made it!(author)2010-05-20

also, it seems like something should be connected to pin five on the 555 timer since its the reset pin

pcmofo made it!(author)2010-05-12

 I have had a few people contact me with the same issue. I myself had to experiment with different caps, resistors, and transistors until I found just the right combination. I have heard the transistor causing the most issues. Like I used a 2n2222 not a 2n2222a... 

Prestond made it!(author)2010-05-13

but the 2n2222 are obsolete are they not? Where could i get one?

pcmofo made it!(author)2010-05-17

 I got mine at a local electronics store.... :-/ sorry I cant be more help. To get the effect you only need to do PWM, which you can do with any simple micro controller, like pic or arduino.

thomas333 made it!(author)2010-02-01

I like your constructable, it's the most simple on the web for creating a nice pulsating LED effect.

Can please specify what kind of transistor you used? Correct me if I'm wrong, but I think I need a PNP 9V transistor with a max current that suits the LEDs.

flof made it!(author)2009-02-22

are you sure the circuit above is right? Threshold (6) and Trigger (2) are both Inputs and there is nothing else connected to them...
I tryed this with a 5v Input and a BC337 instead of the 2N2222.
The LED won't light up until I pull the 100uF but *suprise* then there is no PWM..
Any hints?

pcmofo made it!(author)2009-02-23

I have added a picture of the working bread board design to step 1 and labeled the parts. I hope this clears things up for you. Let me know if it works!

flof made it!(author)2009-02-23

Thanks! The image differs from the drawing. The blue line to pin 7 should go to pin 6? With this wireing it fades in jeah :) but i've never seen it fading out. I'll try with a 2N2222 the next Days. I draw this schema with eagle do you think this is right?

pcmofo made it!(author)2009-02-24

OK It looks like you are close you just have a few things mixed up. Here is what my breadboard pinout is. 1 - Ground + 100uF cap 2 - Jumper to 6 3 - 100k Resistor to transistor Base 4 - Jumper to 8 (+) 5 - NC 6 - Jumper to 2, Jumper to Transistor Base 7 - NC 8 - Power, Transistor Collector, Jumper to 4 Transistor Emitter to 500ohm Resistor 500ohm Resistor is + voltage to all LEDs Pin 1 is just going to ground on your diagram. In reality the C1 is connected to this ground and the + end is connected to the Base on the transistor. Pin 2 is correct except for the C1 as mentioned above. Pin 3 is correct. Pin 4 should be jumped to pin 8, the brown wire in my breadboard. Pin 5 is NC and is correct, Pin 6 is correct. Pin 7 is correct and is NC Pin 8 is correct but should be jumped to pin 4 as stated before. I see your diagram says they are both connected to VCC but they really need to be connected together as this causes the 555 to run in a loop I believe of PWM up and down. I am not sure if this is the cause but it would be worth trying to replicate my bread board exactly. Mostly I just see that C1 is in the wrong place. If you move that it should work. The 100k resistor should be what is causing the fade on and the C1 should be what is causing the fade out rate. So that is most likely why it is not fading out. I look forward to seeing your Eagle schematic when you have it working! (If I had more time I might try making a PCB)

flof made it!(author)2009-02-24

I have a NE555N, a LM555CN and a 7555CN (Phillips).
If I test them with the schema I created (still with a BC337) all fade in and the 7555CN also fades out yeah! I don't know whats the cause of this behaviour... weird analog circuits ;) I'm always open to more theory about it.
About the schema:
Afaik if two Pins are going to GND it doesn't matter which hits GND first. On the breadboard Pin 1 is connected to GND (blue wire hiding line 11 on the breadboard) and without this connection there is no fading (tested ;).
Pin 4 & 8 use both *the same* VCC. If you use Eagle and try to create a board out of this schema the two VCC will be the same signal. So no need to connect them in the schema. To be true, it would be nice to know how to *make different voltage sources* with eagle. I've attached the Eagle schema if someone wants it.

The+End+of+A+Heartache made it!(author)2010-01-11

cant read the skemetics bro, its .tmp

flof made it!(author)2010-01-12

You have to rename the .tmp to .sch!
Download -> open with eagle -> FAIL
Download -> save to disk -> rename to .sch -> open with eagle -> Works
Tested on WinPX, Firefox 3.something, Eagle 5.4.

The+End+of+A+Heartache made it!(author)2010-01-12

oh need to have eagle, sorry
and im running windows7 X64

flof made it!(author)2010-01-12

What did you expect? This is just the original source of the image above...

The+End+of+A+Heartache made it!(author)2010-01-12

im expecting a user friend image that everyone can see XD

pcmofo made it!(author)2009-02-23

I will double check my circuit and upload a picture of my bread board later tonight to be sure but I believe it is correct. I had three different types of transistors and had the best luck with the 2N2222.

The+End+of+A+Heartache made it!(author)2010-01-11

i love your beating heart witha 555timer mod :) i have tooken your design and built one of my own but seems like the polaritys of the build is wrong,... where the capacitor is to the ground is a positive connection on mine and the postive connect to the 2n2222 i have a negative connection... i am using a NE555p chip, a 100uf capacitor and a 100kohm resistor, instead of 4 LED i choosed 2 and applied instead of a 500ohm resistor a 250ohm resistor...

maybe i have designed it wrong... i will try again but do not know why my polaritys were in reverse.

The+End+of+A+Heartache made it!(author)2010-01-11

i redid the skemetic and now it will not work at all.... hmm :/

pcmofo made it!(author)2010-01-12

 I have had a few other people respond that they have not been able to reproduce the exact results I have. I think this is mostly due to the 555 timer type. you may have to experiment with different resistors/caps to find the combo that works best for you. 

The+End+of+A+Heartache made it!(author)2010-01-12

yes, ive been looking through different timers, from the one i used ne555p to ke555 and to op-Amps... i think personally the capacitor is to high for my ne555p timer, i will use a 10uf and a 1uf... i have replaced the 100kohm with a 100kohm pot.. it seems like when looking back at your skemetics there is a slow discharge but a faster charge time

About This Instructable




Bio: I like to take things apart, sometimes they go back together sometimes they end up as something entirely different then where they started.
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