Where to start?

Projects Discussion and Showcase Home Automation and Networked Objects
#1

Hello, I’m new here and new to the world of Arduino. I registered here because I need a device and I just cant seem to find a off the shelf product that meets all of my requirements.

Q: What does this device need to do?
A: Switch power on/off and/or perform an automated powercycle, triggered via ethernet.

Now this seems pretty straightforward, but there are a few problems:

  1. Size, the space available to place this device is very limited, so smaller is better.
  2. Cost, the total cost of parts should be less than $200.
  3. It should be able to pass through IP communication that is not meant for the device itself (essentially a hub-like functionality).

There is a device out there that meets my needs functionality wise, the iBoot by Dataprobe. I own one of these, but they are too expensive and too big.

What I want to do is have a central server powercycle a number of power over ethernet powered devices (basestations). These devices do not comply with regular PoE specs and need their own specific PoE-injector (otherwise a managed PoE switch would do the job). These devices are mounted in some really tight corners, hence the small size needed. Connections available at the devices are very limited too. 1 ethernet cable and 1 230V AC outlet is all I have. Creating more connections is nearly impossible.

So I was thinking about using a network enabled Arduino to control a couple of relays that interrupt the outgoing power of the PoE-injector. Switching the AC to the PoE-injector is also an option, but I was thinking about using the PoE to also power the switching device as the injectors have a bit more capacity than the basestations require.

Like I said, I’m new to this, so… Any ideas where to start??

#2

Sounds like you are most of the way there. And you are right ardunio would be able to do all of this.

Using a relay to switch the output of the POE Injector would probably be the safest method (as it doesn't mean messing with mains).

Depending on the spec of the relay, you might need a transistor between the arduino and relay.

The code wouldn't be very complex. I would strart with the inbuilt server sketch as that will probably make up 80%+ of the code you will need. You will just need to make the arduino respond to the type of request the central server sends (GET or POST requests).

#3
  1. It should be able to pass through IP communication that is not meant for the device itself (essentially a hub-like functionality).

Do you really mean this? You want to implement an ethernet hub? Why?

#4

May I suggest a simpler implementation:

Drop the ethernet. Use RF modules instead to do the POE interruption - there are car garage fob / receiver modules you can buy that feature rolling code security, etc. If it's good enough for a car... Cheap and simple too.

Or use a timer (RTC) to do this at a regular interval (in the middle of the night, for example).

There are relay modules /shields out there that can interface directly with the Arduino. Use a separate switch-mode power supply to supply power via the relay(s) to the POE injector(s). That way you can do a rolling reset, i.e. turn off the base stations sequentially, allow them to reboot before turning off the next one, etc. so you might be able to maintain a wireless network coverage continuously (though degraded temporarily in spots).

Cheers.

#5