Some details and photos. Sorry about not getting the photos out last night. Wife had a bad day at work and we "solved" it by getting plastered.
Note: the board in the photo is a higher end board with lots of ADC (measuring analog sensors), and DC power circuits. It is much more expensive (~$200) than anyone would want for turning rigs on and off. I bought this because I need remote sensor monitoring and out of band power control. Still it should give people some ideas.
My goal is to use a similar lower end board with 8 2A relays and USB interface. I scrapped serial interface idea as I found a board which doesn't have a huge premium for USB over serial. Power is 12VDC supplied by a Molex adapter. Each kit will include the relay board, control software (initially Windows but eventually Windows & Linux) and wiring adapters for power control.
The power control adapter connects to the ATX header on the motherboard. It is connected to the power switch not reset pins.
Why switch power at the motherboard and not from the wall? Cost and safety. To handle full rig current would require using 10A relays and inductive capacitor which add about $20 in cost. Honestly even that is risky. Pulling >1200W could burn the relay and possibly the usb controller. Worse if voltage sags (which can happen) then current rises. 1100W on a 102V circuit is >10A. So to be safe under all conditions 15A/20A relays would be better and that adds about $40.
Switching low voltage DC is safer and easier. Worst case scenario if relay fails in open or closed posistion it is no different than either not pushing or continually pushing the power button on your computer. Failures are "clean" and safe. Motherboards and ATX PSU already have the expensive relays and safety circuitry built in so why not use it.
I tested it with leads as long as 6 feet and switching is reliable. I did 20 on off cycles and had no failed trips. I can test it for longer leads is there is need. Essentially the relay is no different than pressing and holding the power switch.
Configuration requires a little testing. I found it takes 1200 msec to power on rig, and 4000 msec to power off the rig. A nice feature is that is the status of the rig is unknown keeping relay closed for 6500 msec will ensure the rig is now off. (If it was off it will power on and then back off). I call that "forced off". Since the board can't know for sure if a rig is off, "forced off" can be used to put the rig in a known state. It then can be powered on. I imagine this will vary by motherboard but can be tested/verified by simply pressing and holding the power switch.
This afternoon after I get out of some meetings I will post some shots of the (alpha) software.
I have experience to write a windows software. A command line and GUI application for manual control and configuration plus JSON API for extending functionality to third party applications. I will need assistance with porting that over to Linux. Someone has (thankfully) already PM indicating he is interested in helping on the Linux side and based on his coding experience it shouldn't be an issue. I will let him announce it in the thread if he wants it public.
Cost will be ~$100 per kit (controls 8 rigs)
* USB relay board with eight 5A SPDT
* wiring for connectivity, power, and connections to remote rigs (plus some spares)
* open source manual control software plus API which would allow 3rd parties to write automated control (reboot on crashed GPU)
* support & troubleshooting
Update: mini USB relay board.
If there is enough interest I can also offer a 4 rig version for $75. Sorry less relays don't save that much but if someone knows they will never need more 4 rigs switched it might be an option. The mini board would work exactly the same except it would have 4 not 8 5A SPDT relays.
To make this worthwhile I will need interest in at least 10 boards. Sorry but margins are small and my time is valuable. Not asking it as this point but before I order parts I will require a $10 pre-order deposit. I board isn't shipped in 4 weeks (should be faster than that) or final price ends up being >$100 you can cancel and get deposit back. If board is ready for shipping at <=$100 deposit is non-refundable (you could sell your deposit to someone else).
Thoughts, comments, questions, concerns, rants, objections?
Poll
