Throbbing Apple Logo Sticker




Introduction: 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...

Step 1: 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

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!



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25 Discussions

i would like that to do that project, but there's no schematic :(


 Howdy. The PIC10F206-I/P or PIC10F206-E/P are 8-pin DIP (through-hole) versions of the chip.

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

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

Hahahahaha awesome idea. I like to pretend I'm making them throb with the macs a my school, and also with my sisters macs.

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

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 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...

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.

heheh thats cool, i dont know where id put it though :S still very nice !

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.

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!!!

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.

1 reply

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!