Picture of Beating LED Heart Picture Frame
heart 23.jpg
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.
MVI_2444.AVI(640x480) 19 MB
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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 (author)  JorgeTristan1 year ago
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.
McQAC1 year ago
So this is pretty sick. I'm a novice to the umpteenth degree. How would I add a 4026 counter to randomize the lights?
Prestond4 years ago
i can't get my leds to fade out :/
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 ... :)
try lowering the 100k resister to 90k or even less, this worked for me....
Hope it helps someone..
Prestond4 years ago
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.
also, it seems like something should be connected to pin five on the 555 timer since its the reset pin
pcmofo (author)  Prestond4 years ago
 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 pcmofo4 years ago
but the 2n2222 are obsolete are they not? Where could i get one?
pcmofo (author)  Prestond4 years ago
 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.
thomas3335 years ago
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.

flof6 years ago
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 (author)  flof6 years ago
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 pcmofo6 years ago
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 (author)  flof6 years ago
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 pcmofo6 years ago
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.
v2.sch193 KB
cant read the skemetics bro, its .tmp
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.

oh need to have eagle, sorry
and im running windows7 X64
What did you expect? This is just the original source of the image above...
im expecting a user friend image that everyone can see XD
pcmofo (author)  flof6 years ago
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.
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.
i redid the skemetic and now it will not work at all.... hmm :/
pcmofo (author)  The End of A Heartache5 years ago
 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. 
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