Tron bike: it's a 100% clear plastic bike frame with LED edge lighting. The entire frame starts from a single flat sheet of clear polycarbonate (lexan) plastic which is cut into pieces and assembled. LED edge lighting is added to provide great night-time special effects. The bike falls a bit more on the "art" side than the "practical" side as it is heavy and wobbly, but it is rideable and great for cruising town around at night.

The original (un-lit) clear plastic frame concept & design is by saul, who led an intersession class at the MIT Media Lab in 2003 (?) where about 10 students each designed and built a clear plastic bicycle frame. Some of the students modified the frame styling a bit, one of the other frames with a more curvy style is shown below.

After seeing one of the frames around MIT in 2004, I had the idea for customized edge lighting so I built up a frame and added the lighting effects.

The full project here is quite a lot of work unless you have a high-end machine shop at your disposal, but there should be several ideas for you along the way. I've included the CAD files for the plastic frame and the C code for the microcontroller. This is an "after the fact" documentation, i built this about 3 years ago.

As seen in the Wired Blog.  

This article is brought to you by MonkeyLectric and the Monkey Light bike light

Step 1: Tools & Parts You Need

plastic frame:

- a 4' x 8' sheet of 3/8" thick clear polycarbonate
- a 2' x 4' sheet of 1/8" thick clear polycarbonate
- a 2' long, 1" diameter clear polycarbonate rod (handlebar)
- acrylic solvent cement

bike build:

- standard bottom bracket
- standard seatpost & seat
- 26" rear wheel with coaster brake
- 26" front wheel
- threadless headset
- 12" long aluminum fork tube (sized for your headset diameter)
- standard stem
- standard crank arms & pedals

LED edge lighting:

- as many LEDs as you desire (this one has about 200 x 5mm leds, but you probably want to use high-power leds)
- 22 guage wire in 4 colors
- three copies of my simple constant-current led driver circuit, one for each bank of LEDs
- simple Atmel AVR controller circuit which drives three FET's, each fet turns on/off one of the LED banks.


You need to be able to cleanly cut out the plastic frame parts from the sheet of plastic. You might be able to do this with a jigsaw, a dremel tool and a lot of patience, otherwise you'll need a CNC mill or a CNC waterjet cutter.

You will need a bottom bracket tap to cut the threads into the plastic to screw in the bottom bracket, most bike shops probably don't have one of these and you'll have to try a custom frame builder.

A dremel tool to polish any of the plastic edges that don't quite fit.

standard bike tools

soldering iron & pcb assembly gear

Step 2: Cut the Frame Parts!

i've attached a cad file with all the parts needed for the plastic frame.

I ADVISE BEEFING UP THE BOTTOM BRACKET AND REAR WHEEL DROPOUTS BEFORE CUTTING YOUR PARTS. by this i mean: add some extra plastic around the bottom bracket and rear wheel dropout areas as compared to what is shown in the cad files. These two areas failed on my bike, i had to repair them afterwards.

you can also re-draw the outlines of the frame for a custom shape.

Step 3: Frame Assembly

the entire frame fits together using tongue-and-groove assembly, after it is assembled use solvent cement on all the joints. if the fit is very tight use a file or dremel to help, and a hammer. the fork is assembled separately from the frame. there are not so many parts so it should be pretty clear how it all fits together.

i'll highlight a few key areas in the next steps

Step 4: Bottom Bracket

my bottom bracket broke - you should increase the diameter of yours so there is more plastic supporting it. after mine broke i added fiberglass around it, so yours will be a lot neater than what's shown here.

Step 5: Headset & Front Fork

the front fork is assembled separately from the headset & main frame, just like a regular bike.

first assemble the main frame, then install the standard threadless headset bearings into the plastic head.

assemble the fork, then install the fork tube into the plastic, and then attach fork to bike in the usual way.

Step 6: Seat Clamp & Rear Fork & Rear Dropouts

the seat clamp is tightened using the two bolts.

you can see my rear dropouts are reinforced by gluing some extra plastic to make it thicker.

Step 7: The Electrical Circuit & Programming (overview)

I used a very simple circuit here. the LED's are in 3 banks. each bank is all one color of led (one bank is red, one is green, one is blue). all the LED's in a bank are wired in parallel. each bank uses my simple LED constant current source. each bank can be turned on or off using a power mosfet. lastly there is an Atmel AVR microcontroller which turns the 3 mosfets on and off in a few simple patterns, i've attached the C code for the microcontroller.

there are two simple patterns currently programmed:
1) blinking the 3 banks. this is a very epilepsy-inducing pattern, it blinks each bank for 1/7 of a second, in a cycle.

2) color fading. using PWM, it fades each color in and out in a cycle, the same pattern you now see in innumerable chinese 10 cent blinky toys.

Step 8: Adding the Edge Lighting

having all the led's of a single color in parallel dramatically simplifies the wiring job. there are 4 colors of wire routed all over the bike: black (ground), red (red led positive), green (green led positive), and blue (blue led positive).

I used about 200 x 5mm leds for this project, back when i did it high power led's (eg Luxeon) were very expensive. if i did something like this again i would most likely use Luxeons, it would save a lot of work on the lighting install and light up the bike just as well. it wouldn't look quite the same since it would be fewer points of light, but probably just as good anyway.

install leds like this:
- drill a hole deep enough for the led into the plastic
- jam in the led
- bend over the led leads against the frame
- strip a small area off the two wires - it is very convenient here if you have a stripping tool that does not cut the wire
- solder the two wires to the led leads
- coat everything with hot-melt glue or silicone

covering everything with glue made the wiring a lot faster since no tape or shrink-tube is needed. on the downside you can see that the glue job is a big ugly mess.

you can go back and look at all the photos to see how i just routed the 4 wires all over the frame and drilled the leds everywhere.

Step 9: Wiring the Front Fork

to protect the wiring to the fork from ripping out, i added two strong cables which limit the steering angle

Step 10: Circuit Attachment

all the circuit controller stuff is just glued into the middle, and there is a battery pack holder (it runs on 4 x NiMH AA batteries, or plugs into the wall using a 5V 2A wall wart)

Step 11: Other Ideas

the construction method for the lighting was quick-n-dirty, and it made a big mess of the frame which looked a lot nicer before all the wires and glue were stuck on. just doing the wiring neater would help, and making it all one color wires would look better i think, and keeping the glue much more contained.

on a different one of these frames i saw, the plastic edges were all polished mirror-smooth (just like they do on eyeglass lenses sometimes), this is not too hard with a power polishing wheel and looks nice.

it would be great to have a more sophisticated lighting effect, but that would require a lot more wires to get individual control of the leds. the leds i used were from about 2001, new power led's would be a lot brighter and require a lot fewer leds and less wiring.

I've heard of a bike done like this by some university students. ....Brock University (Canada). <br> <br>It be nice to see a video of the steps done to produce a bike like this.
I am not entirely sure i would ride it as Acrylic is very brittle.
all this needs is an LED outlining for the wheels
awesome bike! i want one! but i imagine you cant keep it in the sun for too long...
actually polycarbonate/ is resistant to yellowing from the sun...it's 1 reason why they make R/C car bodies out of it.
i was thinking more about the frame drying out and cracking.
ah I see...it should last a couple years
Very cool build !!!&nbsp;&nbsp; I'd&nbsp; love to see some video .<br />
sure, it has a coaster brake
thanks, I was wondering. At first I thought it might have been fixed gear, which seemed less than ideal with the frame.<br /> <br /> great idea, btw
well i know what i'll be making later lol
where would we get these materials, and how much is this gunna cost? This looks really cool, I'd love to build one.....
You know how much it weighs?
around 30 lb
lol the bike is a pimpmobile
if i built this i would have done some things differently ,starting with the lighting. i would have used rope light [http://www.ultraleds.co.uk/images/neonblue.jpg] or sand the frame to make it look &quot;cloudy&quot;.<br/>
Thank you for the ideas!!! I'm working on tricking out a trike with LEDs for a Halloween parade, and your frame took me in a whole new direction! Great job!
TOTALLY SICK RIDE! all you need to do now is add some led "hokeyspokes" to it and maybe some EL wire for the handlebars. i bet that bike turns heads at night.
Anyone else noticed that there are no breaks? Great job!
breaks? you mean cracks? actually there are some small ones :( but its still in one piece and ridable. as noted in the project the bottom bracket area cracked to failure, but this was more a design problem of not putting thick enough plastic there in the first place.
I think he meant to say <em>brakes</em>. Does this bike have any <em>brakes</em>?<br/>
Correct. That is what I meant
yes it has brakes. the secret to easy custom bike building is to use a rear wheel with a coaster brake. no cables needed!
OK, That's pretty AWESOME!
Very cool. The lighting is great. You did the hard parts, but here are a few easy additions that would complement the assembly. How about: 1. Acrylic rod for the handlebars and seat post 2. Mylar aero wheel covers. Use r/c aircraft mylar to create cheap disc wheels over the spokes. Superglu to rim and washer at hub. Heat a little with hair dryer or heat gun to stretch. Hmmm. maybe I need to do an Instructable for that one. 3. Peel off the saddle pad and replace with transparent gel pads Thanks for posting!
thanks! actually it does have a clear handlebar added after some of the photos were done - see the daylight photos - but no leds in the handlebar yet.
I see the handlebar now. Excellent.
you know there's a company who make car rims out of 2" thick clear lexan if you can manage something like that it would be pretty cool
i wouldn't want to be the guy riding it when it collapses from weather and sun deterioration, but a very cool idea none the less.
This was at the maker faire 2007 wasn't it?
of course!
I have a suggestion for a future upgrade to this, you could fit in a few speakers and a psp sized compartment to put an mp3 player in to make it a DUB bike.
i get the feeling this is gonna be the start of a new sub group of instructibles for instance a clear lexan skate boar w lighting would look like a hover board at night
heh that would be cool
lol yea you could hve the tusks flash
tusks? Do you have a prehistoric board or something? Or did you mean trucks?
my first post i said clear skate BOAR instead of BOARD
is it safe to ride? that stuff cracks and splits into pointy shards. great idea, but let's test a rejected one to distruction before riding it. I put led's on electric r/c planes too!
acrylic makes shards, not polycarbonate
oh, didn't know. I used plexi on some projects. It sucks. If lexan is that good, I will keep it in mind for the next 1. thanks
Awesome. Inspiring for both the LED aspects but mostly for the bike design.
this is really nice. i think ive found a good project for my schools cnc machine. oh and for those handlebar wires you might consider having contacts like in an electric motor. that way no matter how far you turn the handlebars the wires dont break.
yes! a commutator would be a good way to do the handlebar wires so they couldn't break.
It'd be really neat to run this off of a dynamo attached to the wheel. You could easily enough just use a small PMDC motor as a generator. Set the gear ratio right to get it to the voltage you want- however your voltage will be all over the place, so it would be better to use it in alternator fashion- the dynamo charges a battery that powers the lights when you're not moving. I imagine that this would end up just augmenting how long the battery lasts rather than generating enough power for the LEDs continuously. Lets see- 200 LED, say 30ma/5v each = 0.15W each x 200 = 30W, call the generator efficiency 70%, get around 43W. Lance Armstrong can put out 300W continuously, and a reasonably fit person can expect 75-110w over 4 hours, so a 43W on a bicycle is not insignificant!<br/><br/>Any one of these motors would work: <a rel="nofollow" href="http://www.robotmarketplace.com/marketplace_motorsmisc.html">http://www.robotmarketplace.com/marketplace_motorsmisc.html</a><br/>The HTI one has 70% efficiency and a Kv of 1260, so it would need to turn at least 18000RPM to get 14v, charging voltage for a 12v lead acid. A bike going 10MPH with 26&quot; wheels will have wheels turning at 130rpm. 18000/120=147:1 gear ratio! Assume friction drive, the roller would have to be 147 times smaller than the wheel, or 0.177&quot; - just undr 3/16 of an inch. Not feasible- I'd feel comfortable with a minimum roller diameter of 3/4&quot;- a 35:1 ratio, giving 4550rpm at the motor. So to get 14v we'd need a motor with kV of 325. That's in the realm of very large motors! A popular 1.1kW PMDC motor that I know has a kV of 186, and that's quite a big motor. <br/><br/>So to conclude: using a dynamo is not really a good solution unless you can find a motor with a low kV.<br/>
yeah, i think this is why i opted for 4 x AA rechargeable batteries. it runs about 2 hours on a charge because the average power draw is about 8W. the LED's are never all on at the same time, we're always blinking them or fading them.
Love it!!
How durable is the frame? Also, do you have any video footage of this during the night time? I would enjoy seeing it lit up while being ridden.
it is not as strong or durable as a metal frame, but good enough for frequent "cruising around town" use. you just have to be a bit gentle and avoid slamming curbs at high speed. i know at least a couple people from MIT that rode theirs to campus daily for quite some time, i've probably put 50 1-mile trips on mine. as noted, i did break & repair my bottom bracket but this is correctable by tweaking the cad files for the frame.
Very good work.

About This Instructable




Bio: Dan Goldwater is a co-founder of Instructables. Currently he operates MonkeyLectric where he develops revolutionary bike lighting products.
More by dan:Giant Xylophone made from Bed Slats Easy Mothers Day Fudge (with small child) Mosaic Tile Pixel Art Car 
Add instructable to: