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[on:]

Ok, just before I get going on such a project I'm going to check I've got the idea right, but I'm not sure about components.

Aim: To remotely turn on PC within a certain radius - pretty much turn it on from another room. WoL has failed utterly - must be a motherboard / router issue or other, but it cannot be woken via magic packets.

Goal: Wire up a relay to the power switch. This is controlled by an arduino (on stripboard in the final build) which receives input from an RF 433MHz RX module. The other TX module will be connected to another arduino on stripboard on a project box with a button.

Use: Press the button, and the RX/TX sends it to the PC side (with a suitable code to avoid intermittent interference setting it off), where the arduino energises the relay, turning the power switch on and booting the PC. Continual hold over the button (5 secs) would also perform a hard shutdown of the PC, allowing for crash full reset and reboot should the need arise.

What sort of relay would I need for such a project? And does this sound like the best way of going about it?

Thanks for any input.

[Reply #1 on:]

For a simpler solution, you could just get an RF remote control kit, that closes a relay when you press a button.

Or, for a bit more of a challenge, get a cheap wireless doorbell and modify the output to activate a transistor to drive a relay to 'press the button' on the computer.

[Reply #2 on:]

I'd thought about the wireless doorbell option, but had thought that the circuitry would 'get in the way' - the bell tone isn't continuous, so I couldn't do the switch off option. I guess with investigation there might be a part that is simply energised dependant on the bell push. Also, I was thinking of possibly extending the system with an old phone in the future, so I could dial in a switch on signal, wired to the vibrator or speaker in the phone I guess. Just throwing ideas around until I get a decent idea for remote switch on. And rf remote kits - as far as I can tell they are overly expensive for this kind of job, unless anyone knows of a cheaper alternative?

[Reply #3 on:]

WoL has failed utterly - must be a motherboard / router issue or other, but it cannot be woken via magic packets.

Can you tell more about the PC, type version name of the motherboard / network card?

[Reply #4 on:]

WoL has failed utterly - must be a motherboard / router issue or other, but it cannot be woken via magic packets.

It may very well be a router issue, especially if you are using a Linksys WRT54G since it does not allow port forwarding to the broadcast address, xxx.xxx.xxx.255.  Do a search for 'wol wrt54g' for more information and some work-arounds.

Don

[Reply #5 on:]

MB Asus P4i65G

Northbridge   Intel i865P/PE/G/i848P rev. A2
Southbridge      Intel 82801EB (ICH5) rev. 02

Network integrated to MB:

Realtek RTL8139/810x Family Fast Ethernet NIC

Router: Belkin F5D7633-4 Firmware Version    1.00.25

But I don't think that will help any. WoL is such a PITA with little to no reliability between hardware that when it doesn't work, it doesn't work for good it seems.

[Reply #6 on:]

The network card supports WOL according to - http://www.realtek.com.tw/products/productsView.aspx?Langid=1&PFid=6&Level=5&Conn=4&ProdID=16

Not your network card but these things need to be done - http://computerboom.blogspot.com/2008/12/howto-enable-wol-wake-on-lan-for-asus.html-

hope this brings you a step further,
rob

[Reply #7 on:]

Not really, as any setting for it fails to work. RTL8139 does not support WOL RTL8139A does support WOL. At any rate, WoL requires a very specific set of hardware conditions to work which it seems for what I have doesn't allow it. For some it is a few clicks and simple, for others the setup just doesn't work because of differing hardware.  Don't take this the wrong way but I'm not a beginner with a PC, so I can read up about my network card and how to enable WoL and troubleshoot sending magic packets through ports and forwarding on the router. It seems like WoL is impossible with my current setup, from MB/Ethernet card/Router/PSU or other. It's not like I haven't tried.

Besides, I'd prefer to build a one size fits all solution that can be wired in and out of any PC that I have or will get in the future. Anyone know of a relay that would be appropriate for the task?

[Reply #8 on:]

If you're just doing a one-off, have you thought about a power switch tail (http://www.adafruit.com/products/268 , http://www.sparkfun.com/products/9842) ? Combining that with a BIOS setting to "turn on when power is restored" (aka AC Power Loss Restart: enabled) might be all you need.

(I've been thinking about a watchdog for one of my machines using the power switch tail - but haven't got 'round to it yet.)

[Reply #9 on:]

Anyone know of a relay that would be appropriate for the task?

You can use almost any relay that has a set of normally open contacts.  I assume that you will wire it in parallel with the power switch on your computer which, judging from the size of the wires that go between that switch and the motherboard pins, switches a very small current.

The Omron G5Q-1A4-DC5 (http://www.omron.com/ecb/products/pry/121/g5q.html) would be suitable.  They are available from many of the usual suspects (http://www.mouser.com/ProductDetail/Omron/G5Q-1A4-DC5/?qs=HDDQUw%2F3PhpKkEmyQfNpeQ%3D%3D) or you could break open a PowerSwitchTail and take the Omron relay out of it.

Don

[Reply #10 on:]

Interesting product that power switch tail, but I'm in the UK - seems to be a US device? I was thinking of rf on/off power sockets at one point, but they are quite expensive - I have most of the stuff here for building an arduino version apart from the relay and project box. Maybe I will get some RF controlled sockets, as with multiple sockets I could also have remote control of other sockets in the house as a bonus.

[Reply #11 on:]

Interesting product that power switch tail ...

It's nicely packaged and good for those who don't have a good collection of parts but there's really not very much inside it.

... but I'm in the UK ...

You can expect to get more relevant responses in the future if you fill in the 'location' information in your forum profile. 

Don

[Reply #12 on:]

Pretty sure an opto would be better on the power switch as it is low voltage and low current so a relay is very over the top.

Arduino sounds very very OTT for this - just get a simple on/off wireless link connected to an opto.

[Reply #13 on:]

What would be a cheap solution to a simple wireless on/off link?

And the arudino was to extend the project in the future, so you could activate it via phone, internet or close range wireless, building in these things as it went along.