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Picture of Throbbing Apple Logo Sticker
This little gizmo adds the iconic "sleeping Mac throb" to an ordinary Apple logo decal.

The idea for this came about when passing by the Apple Store in Palo Alto, California late one night. After hours, when the store is "asleep," the lighted logos out front pulsate just like the power indicator on a sleeping Mac, and I just about fell over laughing. Unrelated, the following day a friend showed me his new Toyota Yaris, an adorable little economy car whose resemblance to the original "jelly bean" iMac was made even more apparent by the Apple logo decal he'd placed on the back window. The two just screamed to be combined...
 
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Step 1: The Device

Picture of The Device
I'd been trying to cook up any sort of simple project using one of Microchip's PIC10 microcontrollers, a minimalist programmable device costing less than 70 cents apiece. Just a few parts are required:

- The microcontroller itself. In this case I used a surface-mount PIC10F206 as it's what I had on hand, but just about any simple microcontroller will do provided you have the facilities to program it.
- A white LED. I've made throbbers using both surface-mount and 3mm through-hole varieties.
- A 3 volt lithium coin cell (CR2032 in this case).
- Battery holder.
- Circuit board to contain the components. Since I was using surface-mount parts, I opted to etch something for the occasion. If using through-hole components, the design is simple enough that a small piece of PCB perfboard with wire jumpers is likely sufficient.
- A clear rubber suction cup; pack of six from local hardware store.
- Glue of some sort. Hot-melt glue, silicone adhesive or cyanoacrylate "Krazy Glue" should all work fine.
- Apple logo decal adhered to a clear glass window.

Two components that typically appear in microcontroller and LED projects are conspicuously absent: there's no current-limiting resistor for the LED (the lithium watch battery used is intrinsically limited in current), and there's no decoupling capacitor across the microcontroller's power leads (simply wasn't needed in this noncritical application).

Step 2: The Code

Here's the PIC assembly source code for the project.

The intensity of the LED is varied using pulse width modulation (PWM). Other Instructables and tutorials elsewhere already cover this in much better detail than I could. No offense intended in suggesting searching around elsewhere if you're not yet familiar with the theory.

The PWM duty cycle does not ramp up and down linearly. Gamma correction creates an exponential ramp that the eye perceives as a near-linear increase in brightness. Because I'm lazy and because so little program space was being used, rather than work out an exponentiation function I simply have a big table of precomputed gamma-corrected values. The PIC10F206 had enough space to contain this table, but a more constrained device might not have this luxury and actual math code will be needed.

One pin from the PIC (GP2) is used for output. This pin was chosen as I might later decide to use this chip's comparator function (available on pins GP0 and GP1) to detect nighttime or shade and enable the throb only when sufficiently dark. As it is, the device just throbs endlessly when the battery is installed, regardless of environment. The exponential PWM duty cycle means the LED is off most of the time, and a fresh battery can run the device continuously for a couple of weeks.

Step 3: The End Product

Picture of The End Product
Once assembled, the throbber is simply attached (by suction cup) to the window directly behind the logo decal, and the battery is then inserted.

The attached QuickTime movie (just below the image) shows the throbber in action. The suction cup I used here has these concentric rings that detract from the final appearance, but I've since found smooth suction cups that look much better.

A couple of final notes on responsible throbbing: first, if you plan on putting one of these on your car, be aware that states and municipalities may have laws prohibiting certain placement and colors of lights on vehicles. You might want to add a switch so it's only visible when parked. Second, some communities may mandate recycling for all or for certain types of batteries. Both of these regulations vary by location, so you'll need to do your own research for proper use.

This almost certainly appears pathetically fanboyish. Actually I own and enjoy using all manner of different systems on a daily basis; this was just something for a chuckle. Please, no petty flame wars, let's just enjoy for what it is. Thanks!
nodoubtman3 years ago
i would like that to do that project, but there's no schematic :(

thanks!
nodoubtman3 years ago
Do you have the schematic please?

thanks! :)
Good night! :)
iBOLIT4 years ago
Pleace, upload .hex file.
matroska5 years ago
 Ironman, anyone?
hax0r5 years ago
From here http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en020032 can you please tell me which to buy that will work that is not surface mount?

Thank you
pburgess (author)  hax0r5 years ago
 Howdy. The PIC10F206-I/P or PIC10F206-E/P are 8-pin DIP (through-hole) versions of the chip.
hax0r pburgess5 years ago
So either of those would work?
ABeardedRev6 years ago
is there anyway I could purchase one of these from you? Like the guy above, my soldering skills are not what they could be... I make a mess of things. hah let me know
wee_man6 years ago
very nice i just coding it in i removed the code about if power is on and that i just wanted to see the cool lighting effects
Mr. Twist6 years ago
Hahahahaha awesome idea. I like to pretend I'm making them throb with the macs a my school, and also with my sisters macs.
mweston6 years ago
I agree, My friend and I both thought they were awesome and due to my lack of time (other projects and getting ready for school) I would be willing to pitch in some money to buy one!!! And you don't have to include the sticker considering most of us have one, and plus if you ask the Apple store the always give you like a sheet of em. To end my babbling I will finish off saying that personally I would leave out the sticker and stick it on the rear window of our car and have it throb when the car is off or something like that - making me look like and apple enthusiast
DragonDon7 years ago
If you ever start to make these to sell, let me know so we can get you setup with a website! This is such a cool thing....thinkgeek.com would love it! I definitely want to know when you make these! I _might_ be able to do it but as someone else said, soldering skills, not ot mention the controller thing, would be a challenge for me. I'm better with websites that I am with microcontrollers and such...
jillg7 years ago
thats waaaay cooler than a suction cup garfield although if you leave the code alone but just attach a light sensor found in nightlights so that it will only turn on when it gets dark it will look like a sticker by day and a throbbing light by night. also it would save battery.
=SMART=7 years ago
heheh thats cool, i dont know where id put it though :S still very nice !
vidarbox7 years ago
I also would be interested in purchasing a preassmbled unit for use with the 3.3v (if I remember correctly), power lead from a standard atx motherboard. Working on a case mod (non-hackintosh), and would love to use this idea for it. I know the new Antec case that Psystar uses has a dual-color Blue/Orange module for their power led/button. On - Blue, HDD Activity - Orange/Blue, Sleep - Blinking Blue.
-Cry_Wolf7 years ago
Could i just buy one off of you? This is a little too involved for my soldfering skills! i want one for my IBM aptiva converted to iMac.

the pics:
http://www.ipodhacking.com/forum/picture.php?albumid=33&pictureid=112
http://www.ipodhacking.com/forum/picture.php?albumid=33&pictureid=120
pburgess (author)  -Cry_Wolf7 years ago
We could probably arrange something, sure. Question on your project though: is this a Mac motherboard and guts put into an Aptiva case, or is it PC internals dressed up Mac-like? If the former, there should already be a "sleeping" LED connection you can tap on the motherboard, no need for all this additional microcontroller stuff. If the latter, do you want it always "throbbing," or only when the system is actually asleep? The "always" case is much simpler, we'd just need to tap 5 volts from one of the drive connections.
Sorry about my late response! my computer does not have any apple parts at all, it is using a biostar mb with a 2.8ghz Pentium 4. It is (almost) running iAtkos 2.0, which is leopard 'modded' to work with standard Intel systems. Contact me via PM or email (i think it is displayed in my profile). Thanks!!!
akimbo m7 years ago
Oh and Btw, what do you think about adding a hacked garden light to act as a power source for this project? Obviously not portable but its works if it is for car use.
pburgess (author)  akimbo m7 years ago
I've considered this, and pried open one of those solar garden lights for ideas, but unfortunately my electronics-fu is weak...I'm still a little lost as to how the voltage from a single rechargeable cell (1.2V) is stepped up to run the 3V white LED...then got distracted with other projects in the interim. Will update this if I ever puzzle it out though, thanks!
I think they stick in one of those voltage booster circuits in there (cheaper than 3v worth of solar panel). I have seen the odd 2 cell light, but they're a pretty rare bird. People throw out solar lights all the time, usually if the NiCd packs it in, or some part of the cheap plastic housing breaks. I think I have about 50 of the things now, in various states of function.
Great idea!.. The only issue would be reduced neatness factor. :-( K.
LinuxH4x0r7 years ago
Very nice! I was planning on making my computer "breathe" sort of like this
PKM7 years ago
(contemplates designing a colour-cycling Windows logo and a little animatronic dancing penguin for similar back-window displays) (decides against it) Presumably, you could use the PIC program space for a table of on-off durations to be used with a simple timing loop, so your logo could pulse out sequences of primes or the morse code for "MORSE RULEZ OK HAM RADIO FTW" or something? I think this is actually quite a versatile platform for lighting effects... +
Very clever and neat! Kudos!.. K.