THIS INFORMATION IS VERY OLD!!!
**NEW!! - ***Click here for latest assembly intructions***
Craft, a sister magazine of Make, is about to publish a DIY LED Hula Hoop article in Volume 6 due on the shelves Feb 5th. It caught my eye because I featured jeffkobi’s instructable months ago and planned to create my own DIY instructions using translucent tubing. Obviously Craft beat me to it. If you are a Craft subscriber you can read the digital edition right now. (click on little blue monitor icon)
Their instructions involve using translucent tubing, color LEDs, resistors, a switch and a battery.
After you are done reading the tutorial, depending on your expertise, you might be left with a few unanswered questions, like:
-How do I choose LEDs with the same Voltage Drop?
-What resistor value do I need for these LEDs?
-How exactly do I strip the wire with a razor blade?
Then you are likely to ask:
-How much is this all going to cost me?
-Can I just buy 10ft of tubing instead of 100ft?
The above are all potential barriers that may prevent you from trying this out. I’d like to avoid that.
In this article I will answer the above technical questions, but I will also show you how much you can save by buying a kit that includes a pre-cut 11ft tube with all the parts you need to make just one LED Hula Hoop. This saves you time, money, and reduces wasted tubing. In the process you’ll also see where you can buy the parts on your own if you dont believe in saving money, or plan to make 10 hoops anyway
So lets start with LED selection:
***By the way, if you want the latest and greatest LED Hula Hoop Making instructions you should skip over to this other page. The post you are reading is quite old****
In the begining of the Craft article it mentions “be sure to research each part and its specs when creating the circuit design. Each LED for this project was chosen for its similar voltage drop, making things simpler by requiring only one value of resistor.”
Here is a list of LED colors and their typical voltage drops (Vf).
RED and Yellow both have 1.8 to 2.4Vf
BLUE, GREEN and White vary from 3 to 3.6Vf
Color changing LEDs are about 3.5Vf (these cycle through all colors on their own)
For simplicity lets put the color changing LED with Blue, Green, and White. In Craft they used 6 color changing LEDs, so I would assume the others were split between blue and green, I am not sure if they used white. Even though you dont use the red and yellow LEDs you get those colors from the flashing LEDs.
In any case the Vf ranges from 3 to 3.6, so you can average that out to 3.3Vf.
I am no longer offering resistors in my kit so I have crossed out this section to avoid confusion. The reason you wont need resistors with my kit is becuase I have selected LEDs that have a Vf very close to or above 3.6V. So when you connect a 3.6V battery to it the LED will not draw more than its rated current. Eliminating the resisotors makes assembly easier. In fact it the LED legs can be “twist tied” to the exposed copper of the wire and you dont even have to solder it. But hey, you should be reading the latest assembly instructions. So stop reading this post, it’s old!
This part is pretty easy. Your battery voltage is 3.6V and you want to limit current to 20mA max for each LED..
So 3.6V-3.3V= 0.3V. And 0.3V / 0.020A = 15 ohms
Tips for stripping the wire
The Craft article instructs you to strip insulation away at different intervals on the wire using a razor. I dont really know why they dont include wire strippers in the tool set, but unless you have used a razor that way before I would avoid it. You risk cutting through the wire or your fingers. I would seriously recommend this adjustable wire stripper, it’s really cheap and allows you to strip the wire in the middle of its length without any risk of cutting it. Thanks again to jeffkobi for the tip. Unfortunately they have a $10 mininum plus shipping, so if you only need that tool you can buy it from me for less and combine it with another order. You can see a video demonstration below.
Easy Switch Installation
In the Craft Magazine instructions it mentions that you can press the switch into a hole you cut in the tube and hot glue or epoxy it into place.
Please DO NOT use superglue. I tried in on a switch and it flowed through the entire mechanism and froze the switch. Epoxy should work better since its less fluid, but stay away from the moving parts of the switch. Hot glue is probably the safest, but I have heard some people’s switch still gets accidentally pushed into the tube.
On recommendation I can make is to modify the switch so that it sits on top of the surface of the tube. Here are some photos to demonstrate.
Basically you bend out the metal tabs up.
You can also snip off the black plastic switch if you want it to be less pronounced.
3/4 inch tube 100ft roll - $37.75 from usplastic.com. Price includes shipping in the U.S.
Barbed pipe fitting – $0.37 found at Lowes (not including tax)
22AWG white hook-up wire – $5.75 + $7 shipping from www.allelectronics.com
White electrical tape – We’ll consider this optional. You can use standard electrical tape if you want. Or you can find this at an art store.
Green and Blue LED* – $0.25 x 15 pcs (cost ranges from 0.10 to $1, the list makes me dizzy so lets just pick 0.25 as an average)
Shipping from Mouser = $6
Color changing LEDs – $1.50 x 6=$9 + $7 shipping (i cant find them at mouser, but the cheapest ones are at electronics goldmine and that’s a sale price)
If you add all this up you get a total of about
$86 $85 for one hoop you’ll make yourself. Take out the color changing LEDs and its $70 $69.
What about tools?
Well I’ll assume you own soldering iron, pliers, wire cutters, measuring tape and even a hot glue gun. But do you have a PVC cutter? You’ll want to use it to make sure your cut is perpendicular to the tube. The cheapest one I found was at Sears for $15. If you plan on cutting more tubes down the road it’s worth the investment, but if you just want to make one hoop it’s kind of silly to spend the money.
Add that tool to your parts total and you are now up to $100. Kind of a lot to spend when you are making something yourself.
Did you know you can have one made for you for $95 at superhooper.org with static LEDs and $175 for color changing LEDs?
Buy the DIY LED Hula Hoop Kit
Save Time Save Money
To make it more affordable for you to try this DIY I am offering a parts kit for only $49
It will include:
10.5 feet of 3/4″ OD Natural Color HDPE Tubing
(translucent white-enough for 40″ diameter hoop)
21 LEDs: 7 Blue, 8 Green, and 6 color changing.
21 matching resistors.
22 feet of 22AWG insulated wire-white or clear
Pipe Fitting – (Tube Coupler)
3.6V Battery with leads
If you dont need the color changing LEDs you can substitute them for blue, green or even white and only pay $39.
By the way if you thought Hula Hooping was just for kids try googling “burning man” or check out this video and some links below.
And in case you are wondering what Color changing LEDs look like, here is a video of one held inside a short white HDPE tube. ** This is not necessarily what arrives in the Kit.