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Picture of Building a
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Although it's not a scary addition to our Halloween decor, I built a lighted sidewalk (the famous effect from Michael Jackson's "Billie Jean" video) to entertain party guests and treat-or-treaters on their way to our door.

Only the wiring was a little tedious, the rest of the construction was pretty simple, and we've gotten lots of great comments and impromptu dancing.



 
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Step 1: Goals

Picture of Goals
First I came up with these goals:
  • Keep any additional platform low to ground. I don't want people to feel like they're stepping up onto something.
  • Span the whole 12-15 length of our sidewalk. It wouldn't look too cool if only a few feet were done.
  • Outdoor-friendly and fairly immune to moisture (we typically get rain in October).
  • And most of all it would have to work with fairly light people, but not crumble under foot of heavier ones. I had to figure people might start dancing on this, so it'd have to take a fair bit of abuse.

Step 2: Choosing panels and lights

I considered various light sources- everything from those closet tap lights, to rope lighting. I decided I wanted to stick with low voltage just in case there were any moisture issues; I didn't want to get into putting this thing on a GFCI or something. For the best combination of low power, low cost, good brightness, and instant-on behavior I decided on ultra bright white LEDs. I decided to use just two LEDs per step. In retrospect, maybe using 4 per step would give a more even light spread, but two aren't bad at all and plenty bright.

Next I had to think about the means to make a translucent step that could easily support 300 lbs or more. Acrylic was a pretty easy choice given other materials (like polycarbonate) are either more expensive or harder to work with. I did some crude calculations to determine that 1/2 inch panels would be sufficiently strong if supported on 4 sides. Our sidewalk extends 12 feet from the front door with a 3 foot jog at the end. I decided on using six panels, each 2 feet square, to span the distance. There would be roughly a foot or more on each end of the sidewalk not accounted for, but it'd work out pretty good.

I left the paper layer on what would be the top side of the panels. It was already a decent color and it diffused the LED light very well. It also protected the acrylic, in case I reuse it for a different project in the future.

Step 3: Wiring

Picture of Wiring
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The circuit I came up with was a pretty simple parallel arrangement of two switches and two LEDs (first image). This wiring would be repeated for each step.

Things got trickier though when I had to figure out how to actually run the wiring to have the switches and lights in the desired locations. After folding the schematic around, the circuit for each step became more complicated (second image).

Each step is modular in that each was wired separately, and tested, and later they were all interconnected. Running the wires was tedious. The first step probably took 45 minutes to wire, and each to follow went progressively faster. By the time I got to the sixth one, I was running wire and soldering without thinking and finished it in about 20 minutes.

Through testing (the specs weren't published) the LEDs I bought needed around 3 volts. Since the LEDs were in parallel and each step parallel with each other, I found I could run the whole thing off only two AA batteries (in series). I did add a second set of AA's in parallel, just to ensure long battery life, but it wasn't necessary since the bulbs are generally only on for short durations.

Step 4: Cheap and reliable pressure switches

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The real trick was thinking of a switching mechanism. I considered micro switches, limit switches, and finally decided to keep it simple (and cheap!) and make a home-brewed pressure switch. My idea was to tape a wire to the upper (acrylic) and lower (frame) pieces of each step with some foil duct tape and separate them with a bit of weather stripping (3/8" thick). The panel sits on top of the weather stripping and as it's depressed, the two pieces of foil make contact and the lights go on. Once the weight is off the step, the weather stripping springs back, and opens the switch.

I decided to place two switches per each step on the edges you walk across. Closing either or both switches would complete the circuit. The good thing about this is that as you're walking along, even if you just catch the edge of the next step, it will light. Having to step in the center of each step would be much less effective.

Adjusting the sensitivity of the switches is easily done by changing the length of weather stripping and how close it is to the foil switch.

Step 5: Framing it in

The last thing to determine was the structure holding the panels To keep the whole thing low I built the structure using 2x2's and 2x4's laying flat. This limited the height to only about an inch and a half. The 2x2's were used to make a square frame to support each panel. The 2x4's were just used to flesh out the sides of the sidewalk to add extra width. I also used a bit of 1x2 sticking up slightly between each 2x2 box to fill the 'gap' that would be between panels.

Step 6: Final Assembly and Results

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It takes two people to move the sidewalk into place. Since the acrylic panels essentially rest on the frame, I install them last. One panel at a time I connect the two wires from the panel to the bare wires on either side of the step.

The end result is fantastic. Treat-or-Treaters are shocked when they notice the sidewalk lighting up as they approach the house. The parents are usually the ones who recognize the original inspiration, but even young kids love it without knowing anything about "Billie Jean". We got many excited compliments like "your sidewalk ROCKS" and "this is SO awesome" as they bounded back and forth over the steps.
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xadevox5 years ago
where can i get acrylic panels and how much are they?
flaming_pele! (author)  xadevox5 years ago
Most hardware stores don't carry acrylic that is thick enough, so you need to look for a plastics supplier. If you can find something local to you, you'll save a lot of money in shipping (the panels are pretty heavy). I bought mine online though, somewhere like http://freckleface.com/shopsite_sc/store/html/acrylicsheet.html. The price varies with the size and thickness of panels you use - the 1/2" stuff runs about 9 bucks per square foot.
dang... so if i wanted to make say 20 panels thatd be like $360! dang! haha
actually $720 (20 panels x 4 sq ft each x $9 per sq ft), I wonder why acrylic cost so much. From what I found the frosted/colored translucent panels cost more.
PMadds4 years ago
What is this different-colored material in the middle of the square?
flaming_pele! (author)  PMadds4 years ago
You mean on the acrylic square tilted up in the top part of the picture? That's tan color is the protective paper that's on one side of the plastic when it's shipped. I thought it looked decent and defused the light pretty good so I left it on.
CyborgGold4 years ago
I may be doing something similar to this in the future now... but instead of using multiple LEDs and acrylic... I may use cement with fiber optic cables running through it (found in another instructable I read a while back) and have the loose ends running to the LED. Maybe even find a way to make it water tight so I can have a year round lit pathway.... if I ever find the money for the project I will definitely have to put it on here....
queesy5 years ago
I wish I knew what was going on here Im a fairly "newbie" type of user here. I was really interested in this but I feel there on detailed instructions missing for people like me to actually build this =(
implaxis5 years ago
This helps me with a couple of problems I've been having with my sensors.  I'll have to try those options!
www.instructables.com/id/3D-DDR-Frame-for-PS2/
I love your homemade pressure switch idea.  Just a thought on making assembly easier, if you put the foil duct-tape on as just a portion of a leg of the circut, but cut out a break a second piece of foild on the acrylic could bridge the gap and act as your switch.
Just my idea.
flaming_pele! (author)  roccopeterbilt5 years ago
Great suggestion!
xadevox5 years ago
where can you get weather stripping?
flaming_pele! (author)  xadevox5 years ago
Just a hardware store like Home Depot. It normally is used for windows and doors.
winterfresh5 years ago
 Congrats on your win! Great Instructable!
StkMtd5 years ago
I suppose this is pedantic, but you really ought to have some resistors on those LEDs. Awesome project otherwise. Any reason you used 2 switches here?
flaming_pele! (author)  StkMtd5 years ago
The two switches is just for added sensitivity. These panels are large enough that just stepping toward one edge may not trigger the switch on the opposite side.
ampeyro5 years ago
i've been trying something like this for a long time, but didn't find an effective pressure swich, will you be angry if i use this as "inspiration"?
flaming_pele! (author)  ampeyro5 years ago
Have at it, that's what this site is all about :)
 Video Please!
eoutlaw5 years ago
"I had to figure people might start dancing on this, so it'd have to take a fair bit of abuse."  Haha!  Have they?
flaming_pele! (author)  eoutlaw5 years ago
Oh, absolutely. Everyone from little kids to pizza delivery men. If I keep this intact beyond this year I should add speakers and have your first step trigger the Billie Jean bass line ;)
 You've got to do that!
Yea cause you know people are gonna "Beat it."
Camisado5 years ago
Epic win in it's effing best. 5 stars, voted, subscribed.
This is awesome!  I'd want to make one for a catwalk or something.
soshimo5 years ago
I noticed you didn't have current limiting resisters on your leds.  The forward voltage bias is fixed on leds (depending on the led, color, and manufacturer anywhere between .7vdc to 1.7vdc) but you should still take measures to limit forward current to 20ma (or whatever peak current is for your device).  Typically 220ohm to 470ohm resisters are used.  Also, remember since you are in parallel you will have supply a resister on each current branch or you risk frying the one without a resistor.  You will also notice longer battery life if you limit your current draw on your LED.  I've seen the ultra brights light up plenty on 10ma and they blind at 20ma so it's up to your utilization.

Other than that, great idea and outstanding implementation.  I like your attention to detail.
flaming_pele! (author)  soshimo5 years ago
I lucked out that the forward voltage of my particular LEDs is very close to 3V (I think 3.2 to 3.3). But this is a great point for anyone building something similar, thanks!
canida5 years ago
This is awesome! 
Agreed with the others, video would be great - do you have any friends who can moonwalk?
cancast5 years ago
Would love to see a video of people using it!
Ninzerbean5 years ago
 I think this is really scary, anything to do with him is perfect for Halloween.
You just hurt my feelings lol.

But really, whats your deal with MJ?
 Instructables has a "be nice" policy that I must adhere to. I am a big fan of Instructables.
mskogly5 years ago
Love it! And I second the addition of video to this tutorial. And yes, Billie Jean baseline is a must!
eoutlaw5 years ago
This is so friggin' brilliant!
It would be cool to see someone cover a hallway floor with these things.  Very nice.
Klappstuhl5 years ago
Awesome.

I'll so build one in my apartment, all the way to the toilet! XD
that would be awesome
Uthman5 years ago
this is awesome XD

a video is definitely required
 Great.
Bump, make a videoclip ! :)
lemonie5 years ago
Needs the video...

L
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