6 replies to this topic

[jdev]

First off, Hello everyone... I'm a .net developer with a decent back ground in that, and looking to get into this micro framework and start doing some cool home automation things. So with that being said, remember i'm a total NEWB when it comes to electronics my only exposure there is when I was a kid I received a 300-n-1 project kit (thanks dad!), and made every single project when i was 10 :| and since then haven't done much except for today finding it in a box and taking it apart for parts. (20yrs later KNEW IT WOULD COME IN HANDY) So first question I have is, I've read through the book Getting Started with netduino and it was fun, but what was most interesting (for what I need) was the networking part, soooo... I am going to buy a motion sensor and a relay switch... what i'm confused about is where to start? I want to turn lights On and Off when my child enters/leaves a room (i know they sale these types of things but whats the fun in that?) how can i power my device from standard home wiring(US)? the only cable i "want to run" is network cable to my server, to do the controlling/logging Any help or pointers would GREATLY appreciated looking forward to your answers, Josh

[hanzibal]

Welcome to the forum!

Simplest would be to get a standard 110V to 5V regulated wall adapter, like this one:
http://www.sparkfun.com/products/8269

To only have a single network cable you could also use POE (power over ethernet) that can send 5V power through an unused twisted pair of wires within the network cable.

For the latter, you'll need both an injector (to insert 5V into the cable in one end) and an extractor (to get the 5V out on the Netduino side). Here's a complete set for that:
http://www.sparkfun.com/products/10759

To control lightning fixtures, you'll need a 110V relay that can be controlled by the Netduino. You'll also need some kind of motion sensor to detect when your child enters the room. Beware that working with 110V can be very dangerous and potentially lethal. I'd think twice before installing homemade 110V equipment in my house with respect to both my kids and insurance policies in case of a fire due to electrical malfunction.

[jdev]

Welcome to the forum!

Simplest would be to get a standard 110V to 5V regulated wall adapter, like this one:
http://www.sparkfun.com/products/8269

To only have a single network cable you could also use POE (power over ethernet) that can send 5V power through an unused twisted pair of wires within the network cable.

For the latter, you'll need both an injector (to insert 5V into the cable in one end) and an extractor (to get the 5V out on the Netduino side). Here's a complete set for that:
http://www.sparkfun.com/products/10759

To control lightning fixtures, you'll need a 110V relay that can be controlled by the Netduino. You'll also need some kind of motion sensor to detect when your child enters the room. Beware that working with 110V can be very dangerous and potentially lethal. I'd think twice before installing homemade 110V equipment in my house with respect to both my kids and insurance policies in case of a fire due to electrical malfunction.

Thank you for the reply, I have looked into the POE but then i would need to get a POE switch and a poe shield for each implementation, I guess i could just take apart one of those wall outlets... was just hoping to find some instructions or maybe a cheap breakout board that does it already.

[Mario Vernari]

Hello Josh. Could you draw a sketch about your expected wiring? I mean the kid's room, where's the lamp, the manual switch, the Netduino, etc. The position of these parts could turn dramatically the solution of the problem. Cheers

[hanzibal]

...but then i would need to get a POE switch and a poe shield for each implementation, I guess i could just take apart one of those wall outlets... was just hoping to find some instructions or maybe a cheap breakout board that does it already.

No shields are required, the 5$ cable set I suggested should cover your PoE needs. I'ts not real negotiated PoE (and can't be run through a switch) but it let's you insert and extract just about any voltage into any standard 8-wire TP cable because 10/100 networking only uses 6 wires (3 pairs):
http://www.sparkfun.com/products/10759

...I guess i could just take apart one of those wall outlets

I might be misunderstanding something, but why would you need to take a wall outlet apart?

[Nathan Baker]

because 10/100 networking only uses 6 wires (3 pairs):

Correction, only uses 2 pairs. Orange/Orange White and Green/Green White are used for transmitting and receiving data. A lot of commercial POE systems actually send power over two pairs to achieve higher power transfer. As a telecom contractor, there were many times where I used the Brown/Brown White and Blue/Blue White pairs as either a second Cat 5 cable, a phone line or two, or to bring both DSL lines into the modem that we used for IPTV service. May not be the standard, but the standard doesn't work when you only have one existing Cat 5E and no options for running a new one.
That being said, always be aware of how the jack is wired on any device you are plugging into in the event that that device has the Brown and Blue pairs grounded or otherwise used. Last thing you want to do is short your power supply out! The CAT 5E standard allows for Blue pair to be used as a voice(standard phone), and you may find networking devices passing this through. Some people may see the possibility to use this as a potential power source for your devices while not paying for the electricity if you have a land line, and while this is possible, I would advice against it.

[hanzibal]

Only 2 pairs, well that's even better then! The pair of cables I suggested are very practical when you know what you have in both ends and they're ridiculously cheap in comparison to actual PoE equipment.