Netduino home hardware projects downloads community

Jump to content


The Netduino forums have been replaced by new forums at community.wildernesslabs.co. This site has been preserved for archival purposes only and the ability to make new accounts or posts has been turned off.
Photo

OT: Lamp Powered by Ethernet Switch?

Led ethernet power light

  • Please log in to reply
4 replies to this topic

#1 Chuckles

Chuckles

    Advanced Member

  • Members
  • PipPipPip
  • 40 posts

Posted 05 July 2013 - 03:00 PM

I have a Netduino 2+ that will communicate over ethernet. The ND will have a AC power, and the ethernet switch is also powered by AC. I wanted to find an LED lamp that could be powered by the switch, thinking it would be good to have one less thing in my surge protector.... But web searches have turned up nothing as simple as a lamp that can be powered by a typical switch. Can anyone say why no such devices seem to exist? Thanks.

#2 ziggurat29

ziggurat29

    Advanced Member

  • Members
  • PipPipPip
  • 244 posts

Posted 05 July 2013 - 08:16 PM

it's not clear to me what you are saying.  I'm unclear because:

 

'ethernet switch'  to me means 'a box with a bunch of rj45 jack for switching ethernet packets'.  is that what you mean?  or some other interpretation of 'switch'

 

'led lamp powered by the switch'.  are you meaning: 'Power over Ethernet (PoE), that can power whatever, in this case happens to be an LED lamp'

 

'NP2 will communicate with ethernet'.  I understand that, except how it relates to the switch and the lamp.  Im guessing the so-connected NP2 is controlling the lamp?

 

If you do indeed mean 'I want to have an network controlled LED, managed by the NP2, connected through a PoE capable ethernet switch, and have the NP2 and the lamp be powered that way, without needed yet-another wall wart', here's some things:

 

*  ethernet itself provides no (significant) power, but there is a standard for PoE whereby power can be delivered over the same twisted pair cable used for networking.

*  and there are many non-standard implementations of supplying power over the networking cables, since this double-duty is a fairly common desire

*  you need a switch (or whatever is at the other end of your cable) specifically designed to do this.  It will be marked as being able to do PoE.  If it is not so marked, then consider it not capable, since this is unusual and its not at all free for the manufacturer to support

*  PoE supplies a pretty high voltage (and variable, since it is also subject to all sorts of IR losses along the line), and so will require some sort of regulation at your device anyway

 

It is a nice capability, and it's a real pity it's not more widespread.  My house is littered with wall warts and dangly wires.  You'd think it was the early 1900's.

 

On the other hand, if my interpretation is wildly not what you mean, then nevermind!



#3 Chuckles

Chuckles

    Advanced Member

  • Members
  • PipPipPip
  • 40 posts

Posted 06 July 2013 - 01:41 AM

I apologize for my lack of clarity. I am not asking about PoE. I am asking about using a simple ethernet switch (or hub) with "n" RJ45 twisted pair connections, being able to power a simple light. I understand that there is not a lot of power in each switch port, but I was guessing (hoping?) that maybe using 2-3 of them together could power an LED lamp of some kind. It seems like a simple utilitarian thing, but no one seems to make (or bg about home brew) such a device. Thanks!

#4 ziggurat29

ziggurat29

    Advanced Member

  • Members
  • PipPipPip
  • 244 posts

Posted 06 July 2013 - 01:55 AM

think nothing of it!

I believe the answer to your question is 'no'.  The ethernet switch -- outside of something like PoE -- supplies no power at all to the various ports rj45.  Indeed that is what PoE is for!



#5 nakchak

nakchak

    Advanced Member

  • Members
  • PipPipPip
  • 404 posts
  • LocationBristol, UK

Posted 06 July 2013 - 10:50 AM

You could possibly use a PoE "y" lead where you have a barrel socket for power and a rj45 plug. However unless your hub or switch is PoE capable you almost certainly blow your switch up, and there isn't much if anything in the way of cheap non enterprise (read as Cisco, juniper etc.) poe switches, as poe is generally used for powering ip phones or cameras. That said if you want to reduce the number of wallwarts you have, you could always buy uprated adaptors I.e. 2 or 3000ma then create some leads to power everything of the same voltage as long as you don't exceed the current rating of the adaptor. Nak.





Also tagged with one or more of these keywords: Led, ethernet, power, light

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users

home    hardware    projects    downloads    community    where to buy    contact Copyright © 2016 Wilderness Labs Inc.  |  Legal   |   CC BY-SA
This webpage is licensed under a Creative Commons Attribution-ShareAlike License.