View Full Version : The Hula Hoop From Hell

02-11-2013, 02:58 AM
Hello everybody, I am new to the forum and wanted to introduce myself and my project to y'all.

First let me preface this with I know almost nothing about electronics, ICs, or microprocessors. I have basic electricity and electronics from the Navy some 30 years ago (taught me how to use an O Scope...lol) and anything else of substance I have learned in the past 2 months. I am a software developer by trade but I am currently taking some time off from the real world.

Backk in December my beautiful daughter came to me wanting a digital LED Hula Hoop and "guess what Dad? The one I like only costs $450.00." (where only and $450 go together in her world I do not know). "But Dad, you could probably build one yourself and if you did it well enough you would have a product." Yeah, right...lol.

Anyway, I decided to embark upon the project. I did some basic research into LEDs and how people were putting these together. I then explored the world of microprocessors for 15 or 20 minutes, drew a few quick sketches and then started spending money.

I ended up buying some LPD8806 strips from a U.S. supplier I found. I also bought 2 Picaxe processors and 2 Arduino micros. I started working with the Arduinos (haven't even opened the picaxes yet). I have so far completely destroyed one of the Arduinos and am well on my way to destroying the second one. Sometime during this process I stumbled upon the Teensys and decided to buy 2 Teensy 3.0s. I am currently using the Arduino for my testing but I am getting ready to breadboard one of the Teensys and use it for the final build. I also bought enough tubing for 2 hula hoops one of them is 1 inch tubing and the other is 7/8 inch tubing.

My daughter insists that the 1 inch tubing is too big for what she wants so thus far I have been doing everything with the 7/8 inch stuff. This makes everything harder because everything has to fit into a much tinier space.

I am using 6 3.7v 10440 protected batteries hooked up parallel for the power supply. The batteries are marked as 600mah but from everything I read I will probably not get more than 300mah out of them so it should be a 3.7v power supply at approximately 1800mah.

I have the power supply built and had it piggy backed onto the LED strips. I have had it threaded in the tube once so far. I had to pull it back out because some of the LEDs got screwed up while I was threading it. I have just finished doing the necessary repairs to the LED strip and am preparing for round 2 of the threading.

The final version of this will hopefully have the Teensy 3.0 processor with the micro sd card module attached. A charge circuit (using a sparkfun LIPO charger for that). I am still trying to decide if I am going to introduce a bluetooth module into the mix or whether I am just going to use a usb cable for any programming that needs to be done.

Anyway, not much more to say about the project beyond that. Hopefully you all will be gentle with me as I ask my very newb questions.


02-11-2013, 08:10 AM
I hope you'll post some photos as the project comes together?

02-11-2013, 04:56 PM
Makes me wonder if you and neep don't have similar projects. :D

02-11-2013, 05:07 PM
Yes, I will probably do some pictures along the way.

Yeah, I noticed that neep is trying to put a bunch of stuff in a smalll tube too. Great minds think alike, ya know ;p

Thanx for the replies.

2/11/2012 -

Today I am rebuilding my power supply. It was sloppy and so I am taking a couple of hours to rework it a little prettier.

Woah, just found out I can edit my post hours and hours later. Cool.

I got the power supply rebuilt. Letting some glue set up right now. Also got the teensy into a breadboard with the micro sd card adaptar and got them talking to each other. Good progress for today I guess. Chipping away.

2/12/2013 -

Re positioned the battery protection board and wired the LIPO charger board in. Freaking thing works ;p

Waiting on a few more parts to get here so kind of at a stand still on the electronics for the moment.

Trying to invent a decent threader, I had one I made out of some sheet metal I had and it worked quite well but offered up a couple of issues when it came time to remove it. Hoping to come up with something made out of clear plastic that I can just leave in the tube and reuse if it has to be disassembled in the future.

Also invented a way to mount the electronics today. Figuring it out as I go along.

02-13-2013, 03:42 AM
Ok, as requested, some pics. I will add more as I progress but for now I will post some catch ups.

The initial supplies (back right around Christmas)


My assistants (very important. They are my cheerleaders) Lois is on the left and Peter is on the right.


My work area. I am set up in my basement.


The LPD8806 strip I am working with


02-13-2013, 03:54 AM

Yesterday, rebuilding the power supply. It is piggy backed on the strip. It uses 6 Li-Ion 10440 3.7volts in parallel.


The power components I added today. This is the last battery in the array. To the left is the power protection board (Tenergy 32003) to the right is the lIPo charger (sparkfun https://www.sparkfun.com/products/10401). I am using protected batteries but used the protection board in addition. I have a tendency to blow things up so I figured the double protection couldn't hurt. ;p


The freaking charger works !!!! (I am always amazed when things I do actually work)

http://www.madspiders.com/hoop/charging_384.jpg http://www.madspiders.com/hoop/charging_396.jpg

02-13-2013, 03:54 AM
And still continuing.

This is what the whole strip looks like right now. I have it laid out on the back of the table while I work on it.


And yesterday I started the work with the Teensy. First I bread boarded it, soldered a few pins on and got the SD micro card talking.


That's about it for now. I have some pics of the strips working on an Arduino micro but they are on my phone right now. If I have a chance later I will put up a pic that shows why you shouldn't use a 100watt soldering gun on an Arduino Micro.


02-21-2013, 11:17 PM
Hello again,

I have been quiet for a few days. Doing research and ordering the final pieces I need.

Today I got the tube threaded (again) and this time it appears that I managed to get it in with all LEDs intact. I don't know if I will ever be able to get it unthreaded again but that is a problem for later. For now it is a step forward.

I am still running it off the Arduino for testing. I have about 10 inches of strip still hanging out of one end. That is the area where the processor, fuel gauge and bluetooth modules will go.

I also still have to position the switches. I am waiting for a 3 position (on-on-on) switch I ordered to come in. I plan to have the switch give power from the battery on one side, be off in the middle and give power off the usb on the other side. That way it is pretty unambiguous for me when dealing with the power.

I am still waiting on a fuel gauge from sparkfun and a bluetooth module coming from China. The fuel gauge should be here anytime and the blue tooth should be in next week.

Started playing with sketches a bit and I imagine I will have many questions as I move forward.

I put a vid of it in the tube running the LED belt library from adafruit up on youtube. I don't know if the embed for youtubeis turned on on this board (tried but no good) so I guess I will just post a link.



02-21-2013, 11:58 PM
Looks great!

You could also make a 'learn to hoop' option, using a small segment of lights that revolves around at the speed you need to keep the hoop rotating.
Then all someone needs to do is try and keep the lights in front of him/her :)

Looking forward to a video of it actually being used!

02-22-2013, 12:11 AM
Looks great!

You could also make a 'learn to hoop' option, using a small segment of lights that revolves around at the speed you need to keep the hoop rotating.
Then all someone needs to do is try and keep the lights in front of him/her :)

Looking forward to a video of it actually being used!

That's all I need is more ideas ;p

j/k. Thanks for the idea. I have not started on the actual programming yet. I have sketched out a flow and done a touch of pseudo code but nothing real yet.

edited in: So, I walk away with that idea in my head and now my brain is full of a "learning mode" with several different functions and then accelerometers keeping the light in front of you as the hoop speeds up or slows down, then of course there has to be a way to tell it if you want to go clockwise or counter-clockwise (yeah, I know, flip over the hoop).. lol. I hate my brain.

02-22-2013, 12:22 AM
Hehe, my todo list just keeps on growing too ;)
It was actually the first thing that popped into my mind when I saw the red light (segment?) rotating at the end of the video.

02-22-2013, 02:37 AM
Hehe, my todo list just keeps on growing too ;)
It was actually the first thing that popped into my mind when I saw the red light (segment?) rotating at the end of the video.

I am an expert at taking 50 cent ideas and turning them into million dollar implementations ;(

05-28-2013, 06:58 PM
Any progress on this?

05-29-2013, 02:23 AM
Any progress on this?

Hello. There has been some progress, nowhere near enough. I have had to take the hoop apart multiple times to address dead LEDs. I have been doing some work on the programming trying to get everything to work together. That is going slowly because there is a lot of learning going on during the process.

I have also not devoted the time and energy necessary as I have been bogged down with some "personal" issues and have allowed them to knock me out. Trying to pick myself up and dust myself off and get back in the saddle.

Thanks for asking.

07-20-2014, 07:33 PM
Quick question as I attempt a similar project. Have no experience with any of this though (doing my research and such) but my question is wether to rig the batteries in a series or parallel? Which should I do our which is better. The hoop I'm attempting is going to have about the same power requirements

07-20-2014, 11:01 PM
You will want to go parallel. Wiring in series would add up voltage, whereas parallel would keep voltage constant while giving you longer life (is more amps). I used a 5v arduino and 5v LEDs with four 14500 batteries (3.7v). I would suggest this write-up: https://philihp.com/blog/2011/diy-led-hula-hoop/

08-13-2014, 01:27 AM
Thanx a ton !!
Any good place to go to find a diagram on wiring the Protection Circuit Board ?