Topic: remotely controlled power switch? (Read 31716 times)

If it works for you it works then...build it, sell it.  I was just offering solutions which are easy and cheap I am not trying to sell kits, but I am planning an Instructable on the topic.  You could make a simple connector which has to be pinned in just like if you were pinning a case switch, my point is that if someone cannot properly pin a Mobo power switch they probably shouldn't be trying to setup a multi computer remote reset. A multimeter should be in every large scale miners possession...if not you do not have the proper tools.  They are like 5 bucks for a cheapo one at Harbor freight that would be good enough for checking the pins.  If you actually buy a decent one it becomes more useful for things like checking PSU voltages and other things.

As far as difficulty finding which pin on the Mobo pinout is the power switch(-) its the one of the 2 that is ground...that easy, all the power switch does is ground a +5v pin.  You can test this with the computer off, just connect one lead of the multimeter to any mobo screw and touch the other lead to the power switch pins til it reads 0 ohms and that is the switch negative.

Which part number "SSR" are you using.  An optotriac (which is a small ssr in itself but is commonly used for driving large triacs) like the MOC3023 runs .33c per unit at the single unit price.  Something like the MOC8016 should work (didn't look too hard at it but I think it would work) is $5.60/10 units...but you still have the polarity issue.  If you sink the drive current to the AVR (active low) from the optoisolator the current to drive it shouldn't be an issue.

Pipesnake: ETA is mid-September.

BkkCoins: There is only 15 usable digital outputs on the PIC-WEB's EXT connector ($50 in the US). Plus you would have to design a separate board for the SSRs and their resistors ($15). In the end it would be twice more expensive per controllable computer ($65 for 15 computers) compared to my solution ($100 for 45 computers).


Find me, on Digikey, any type of opto-isolator comparable to my SSR: $0.75 or less for quantities of one hundred, and that operates with an input current of 1mA. I would be delighted to be shown there is one.


I may sell assembled kits and don't want to tell my clients "GTFO if you don't have a multimeter". I am like Steve Jobs, I care about ease of use


Nope. These are plain standard SSRs. Just go look them up on Digikey, there are plenty in this price range. Once again, I am controlling 5VDC, not 120VAC.


I have not seen this pb. When I stop applying voltage, the SSR output circuit opens...

I don't know why you'd start a new board from scratch for this. I already posted above about the PIC-WEB board available for $29 euro. It has a TCP-IP stack built in with sample web server code, is easy to program with C tools and free PIC tools. It has a ready to use expansion connector that you could hang many SSR off of to control power switches. Seems to have about 28 pins there but I didn't check each one to see if there are special conditions on some.

ETA?

I'll buy a kit.

It all runs on smoke...never forget that.  Once you let the smoke out it doesn't work anymore.

Reading circuit design and embedded hardware threads is good for me, it makes me remember how I keep meaning to learn more about the actual base electrical principles of the computers I work with so much... But haven't yet :p

About those 4 things:
- I want SSRs because I want the electrical circuits to be isolated, for safety. A motherboard or PSU going up in smoke and sending voltage spikes through the power switch wires shouldn't fry my AVR or the 44 other remote-controlled computers...

You can use any optoisolator, doesn't have to be an optotriac.   

- If using transistors, the user would have to know which pin of the power switch is + and which is -, increasing setup complexity for non-technical users.

If they cannot figure out which pin is the pos/neg on the switch they probably shouldn't be trying to pin anything to the Mobo, took me about 2 seconds.  Plus, I checked my MSI vs. an Asrock and they had the exact same pinout for the Mobo power switch pinning...not saying all are, just the 2 I checked.

- My SSRs are cheap ($0.75 in my quantities)
Sounds like you are buying the optotriacs...small components of SSR's that are use to trigger the bigger Triacs in a SSR circuit.  If you were building an SSR that would switch the PSU current you would be looking at around $5/SSR minus the board (and snubber).

- One Arduino Mega would be twice the cost of my AVR board (about $50 vs. $25)
Yep, probably.  But you can use it for other things if you no longer need a resetter. 



Also, have you tested this.  Every time I try to run DC with a Triac it will turn on but it will stick because it requires a negative voltage swing to trigger turn off.  So basically you will trigger it and it will hold the power on.

A quick google search verified what I thought.  Triacs (SSR's) do not properly trigger DC.
http://answers.yahoo.com/question/index?qid=20081024022745AAwQ8nF
http://www.electronicspoint.com/triac-optocoupler-moc3043-switch-12v-dc-t11292.html

So looks like you will have to either use small relays with transistor drivers, DC optoisolators, or just transistors as I was saying before.

Power switches don't fry. But it doesn't mean the 5V standby voltage they are connected to remains perfectly stable or safe, especially given the power supplies failures reported in this community...

If you can have safety and user-friendliness for $0.75, take it

You got any better ideas :p

Ahh, sorry misunderstood since you were talking about isolation.  There's really little danger of voltage spikes over the power switch pin - when was the last time you saw or heard of a fried PC power button?

A diode on the transistor base pin would keep it pretty safe I think, but diode+transistor is pretty similarly priced to your SSRs unless you're buying them in bulk anyway.

Good luck to you, it may be slightly overengineered for the purposes here, but I wouldn't dare kit whatever I'm about to cobble together here with transistors, you're in a better spot for it

Pfft.  I couldn't disagree more.

They are not on the AC side. They control the ATX motherboard power switch (so 5VDC).

What SSRs are you getting so cheap?  When I was looking for these it seemed impossible to find something that could handle >6A for any reasonable price..  how much load are yours rated for on the AC side?

4 things:
- I want SSRs because I want the electrical circuits to be isolated, for safety. A motherboard or PSU going up in smoke and sending voltage spikes through the power switch wires shouldn't fry my AVR or the 44 other remote-controlled computers...
- If using transistors, the user would have to know which pin of the power switch is + and which is -, increasing setup complexity for non-technical users.
- My SSRs are cheap ($0.75 in my quantities)
- One Arduino Mega would be twice the cost of my AVR board (about $50 vs. $25)

Been looking into this for a few days

http://forum.sparkfun.com/viewtopic.php?f=14&t=12563&start=0
http://dataprobe.com/ipio8-web-relay-control.php
http://www.tekkies.co.uk/v2/index.php?option=com_content&view=article&id=24&Itemid=4
http://tuxgraphics.org/electronics/200606/article06061.shtml


I like this one:

http://tuxgraphics.org/electronics/200911/home-automation.shtml

You don't need SSR's for the  front panel switch...its just DC unless you are switching the supply in which case I don't think the necessary Triacs/Optotriacs can be purchased for 2.20/unit.  AVR's are cheap too though.

One arduino mega would switch 54 (also avr based). More if you did some sort of multiplexing.

At any rate simple transistors are fine.

I designed a USB device that can remotely power cycle 45 computers. Total cost in parts is about $100, or $2.20 per computer. This is much more computers and much less expensive than any commercial solution. It is based on an AVR microcontroller, and SSRs connected to the power switches via standard cheap cat5 cables.

Watch my blog for a future announcement. I am probably going to sell kits.

This would work fine...build a serial cable and set it up.  It worked fine with an arduino and transistors so there is no reason a serial cable would not.  Be sure to connect a common ground thats about the only thing that I could see throwing things off.  The MSI boards come with some nice connectors for the board pins, you can actually hook the transistors directly to the connector and then plug it in without having to worry about mis-pinning (connector will only go on one way).  I'll take some pics of what I built so people can see...I should probably post my arduino/processing sketch for my gui control also, been busy and haven't got around to doing a writeup.

I was finally able to really research this some more and it seems like it's pretty trivial.

I'm looking at building mine this weekend with a Jennic ZigBee IC I happen to have.. it's way overkill for this but hey miners are good at utilizing whatever happens to be around in a pinch

I'm almost convinced that this could be done with serial cable + transistors alone just by pulling a serial pin high to trigger the transistor.  ~$5 in parts

A friend and myself are looking at a solution to this, so far it looks like it connects to a computer via USB, wires to up to 14 (!) computer power switches, and supports a keep alive on the computer it is wired to via USB in case it locks up, and will reboot that one as well. Price ranges so far looking like it could be around $50 USD (Or about the same BTC) + shipping from here in Canada. Other possible options include custom cases for it, like mine will likely be in a grey skull so I can make bad jokes about "by the power of greyskull!" We are working out details and software right now, let me know if people are interested. 3D printers are awesome. Send me a PM if you have interest :p