Power over USB ?

[mrmidi]

I just ordered the Lumazoid and I am crazy excited to get it added to my project. I am curious if you could tell me whether or not this USB to Male DC 2.1mm connector will work to power the Lumazoid:

https://www.amazon.com/gp/product/B01N7RL57X

The device I am building has an internal USB hub that provides standard USB power per port, and this would allow me to only have to plug in one thing to have everything else powered over USB.

If this will not work, but you have a different USB powered solution, that would be amazing. I actually went to look in your store first for this cable and, not seeing it, went to Amazon to look for something with matching specs ( center positive PIN, etc ). Totally would have bought this from your store for like $9.99 if you had it there as a working solution 😉

Anyway, thanks again for making the Lumazoid. I was totally going to try to go down this road of making something with just a line input and some Neo Pixels. But for the cost of your device, and the added benefits it comes with is TOTALLY worth the $ !!!

• This topic was modified 7 years, 4 months ago by mrmidi. Reason: fix confusing typo

[Michael]

Thanks for your kind words and especially your enthusiasm. So the thing with USB is that a USB port doesn’t typically supply more than 500mA of current. To power 120 LEDs (a 2m strip, for example), I recommend a 2A power supply. Little phone charger USB adapters often will supply 1.2A for charging, so you could control 60 LEDs with no problem but could run into issues with 120.

Do you know how much current your USB hub can provide on each plug? Maybe it can supply 2A…

[mrmidi]

I am using a 60 LED NeoPixel ( 4 of their 1/4 circle units together as a circle ).

The plan was to use a USB power adapter that you’d use for phone charging, exactly as you stated for it’s 1.2A power.

The cable I linked to was going to connect to a port I am having mounted to an enclosure I’m making. So inside the enclosure the USB & Audio cables would all be hidden. Then I’d just need to hook up an audio and USB cable to the outside to power it.

Mainly, I just was looking to make sure there was no issues with power requirents for your Lumazoid board if it did happen to get powered by a 1.2A source.

[Michael]

That should all work fine, then. The Lumazoid board just needs 5V, and it draws very little current compared to the LEDs. Sounds like a great project. I’d love to see it when you are done.

[mrmidi]

Just posting back to share the start of what I was building with your hardware 😉

Built a NeoPixel EQ Visualizer for my @WeAreROLI gear. Here's the work in progress: pic.twitter.com/65MPmTxNOM

— Briosum (@Briosum) July 28, 2017

I play music as a hobby and wanted to have an instant visualization of the music I was playing as I was playing it to complete the feedback loop of the creation process. ( I was already working on some other web based visualizers that work on MP3 playback [ https://briosum.com/lab/visualizer/ ] … but not real time audio stuff )

Basically, I am using the Lumazoid to control a NeoPixel ring that is attached to the back of an iPad mount. That iPad mount is pointed towards a logo that I cut out of a box lid. I am using epoxy resin to fill the logo, so when the NeoPixel lights shine from inside the box lid it will have two interesting visuals:

1. The light will shine from around the border of the Upad since there is about a 1/4 inch gap for the light to come through around the screen.

2. The rest of the light bounces around inside the lid, where a good portion of it leaks out through the clear Epoxy Resin where I cut out the logo. This means any one on the other side of where I am performing will essentially get to see my logo light up based on whatever music I am playing.

I am working on staining the box an old ebony wood color, and replacing all the hardware ( hinges, latches & handled ) with familiar audio equipment hardware. The rubber feet I am attaching to the bottom and the straps are actually commonly seen on amps. The rest of the hardware ( hingest & latches ) are directly from the travel cases you would use to transport the gear.

Inside the box, I also added some more rubber feet in key place to still allow the board to flex a bit, but also absorb shock where it is required for support. Since I am using this for ROLI Blocks, these are heavy touch based devices, and I was getting a LOT of acoustic noise just from using their Blocks, so this setup greatly dampens that noise by absorbing most of the shock.

Hopefully, in the next week, I will have everything else wrapped up 🙂 I will be posting the final setup on my twitter feed up at https://twitter.com/Briosum

Thanks again for making this awesome hardware. It totally made this a fun project for me !!!

[Michael]

Thanks so much for sharing your progress. It looks great. I’ve never connected a Lumazoid to a ring before, and it really looks nice.

[mrmidi]

OK, hopefully, last follow-up question for this thread…

I notice that when I have the Lumazoid plugged into the powered USB hub, I am getting audio interference through the iOS Lightning Cable that is connected to the same power block.

I have isolated that no other device connected to the USB hub causes the interference ( I have about 3-4 other things plugged into that same hub ). Just reducing the USB cables down to the Lightning Cable and the USB for the Lumazoid triggers the interference sound.

This is not a ground loop hum kind of sound that you would expect from running an audio cable along side a power line … this specifically sounds like little robotic noises. If you turn the knobs on the Lumazoid, you can hear pitch changes. It almost sounds like a signal is being sent over the ground wire or something back to the USB hub, though I am not sure if this is the case.

I am wondering if you have any thoughts on what I might be able to do to resolve this ( other than using the wall power supply, which I was looking to avoid ).

I can plug in any other USB device and not get that sound while the lightning cable is plugged in. But as soon as I unplug the Lumazoid, the noise goes away. I have even tried other USB hubs and each of them creates the same issue. Each time I successfully get power to all the devices plugged in and everything works as expected, except with the Lumazoid plugged in via USB … that interference sound kicks in.

Would love to hear if you have any ideas on what might be causing this and if there are any little gadgets I might be able to put inline for the USB to remove that noise.

[Michael]

Mr. Midi,

Hmm, that is a strange problem. I have never experienced any noise generation from a Lumazoid, but I haven’t used the same setup. The only thing I can think of is to inspect the solder joings on the 3.5mm audio jacks on the Lumazoid to see if there is a short between any pins. In the past, I have accidentally shorted 2 adjacent pins, but this usually just has the effect of attenuating the signal because it shorts the left and right channels together. The ground pin on the jacks is the pin that is furthest away from the signal pins, so it’s unlikely that an audio channel is shorted to ground. But you might want to check with a multimeter to see.

Maybe having an isolated power source for the Lumazoid is necessary for your situation…

[Author]

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