[Noisebridge-discuss] NB Maker Faire table electronics question.

Mitch Altman maltman23 at hotmail.com
Sun Apr 12 21:47:30 UTC 2015

Hi Jarrod,
I don't have much experience with addressable LED strips.  But Dana does, and so does Henner, and so does Torrie.  Maybe contact them on Slack?
But, there are many open source, documented projects online using the addressable WS2812B strips.  And they work, presumably.  So, you can probably copy them.  (Still, it would be good to talk with people who've actually done it.)
An AC outlet usually has 20A at 110V.  That makes 110V * 20A = 2,200W.  That's the amount of power available to you.
If you use 20A at 5V, then you are using 100W.  So, you will still have over 2,000W remaining from the AC outlet.
For the schematic, I can't tell how you are connecting power and ground, or how you are connecting the 1000uF capacitors.  Please make sure that those caps are connected in parallel across +5V and ground (from your schematic, it looks like you are putting them in series).
Mitch (in Paris).

Date: Sun, 12 Apr 2015 02:52:34 -0700
From: hicksu at gmail.com
To: noisebridge-discuss at lists.noisebridge.net
Subject: [Noisebridge-discuss] NB Maker Faire table electronics question.

Hello Noisebridge discussers

My name is Jarrod and I mostly do woodworking projects at NB. So I am very excited to finally be asking an electronics questions to the discussion list. This is in regards to the Maker Faire booth table we're building. I am new to LED/Arduino projects, but want to make sure I get a decent setup put together so others can take things further that I can.
First, I have drawn a PDF diagram of how I think the electrical system inside the table will go together. Here the location of it on the wiki:
1. Does this power scheme make sense, is there a significantly better way?I plan on installing over 4 meters of 60/Meter WS2812B strips. My count is about 301 light sources (>5m). The documentation I have been reading makes it clear that 4m is the max that I can power as a single strip. Based on this I think I can separate the installation into 2 halves. To power theses strips I am thinking I can connect them both to a single 5v 20a power supply based on 301 lights x .06A = 18.06A at full white.
2. Should I not use an Arduino Mega 2560 R3 to run this?  I am concerned that this has the headers installed, would this make the wiring difficult or unreliable?I read that the WS2812Bs will take up a fair about of the Arduino's memory and that the UNO or Pro Mini with 2k SRAM may not be enough to allow additional "libraries". This doesn't mean much to me yet, but the price difference isn't too bad and I would like for others to be able to make this LED installation do other things in the future, so unless there is a "deal breaker" I am not aware of I will stick with it.
3. This table will be connected to a 120VAC outlet for power. With the 5V 20A LED power supply and the 12v Arduino power supply running, is there still a decent amount of electricity left over from a typical 120VAC power outlet to make it worth installing AC power outlets in the table?
I plan to buy parts very soon so any help is appreciated. Please let me know if clarification is needed.

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