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Unattended computer reset on no disk activity

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Meta

New Member
I'm a coder but newbie in electronics. Played a bit with Arduino and helped a friend with an 8051 programmer once.

What I would like to make is a simple circuit that will reset a counter any time there is a signal on the HD LED pins of the mother board and given a number of seconds passing (60 * X) without a counter reset, short the RST pins for one second. The number of minutes can be configured with 4 dip switches (1 - 16).

I can certainly build this with an Arduino, but that would be overkill, expensive and bulky.

Would someone suggest he most cost effective technology to build this and where to start?

Thanks!
 

Ian Rogers

User Extraordinaire
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Most Helpful Member
I'm a coder but newbie in electronics. Played a bit with Arduino and helped a friend with an 8051 programmer once.

What I would like to make is a simple circuit that will reset a counter any time there is a signal on the HD LED pins of the mother board and given a number of seconds passing (60 * X) without a counter reset, short the RST pins for one second. The number of minutes can be configured with 4 dip switches (1 - 16).

I can certainly build this with an Arduino, but that would be overkill, expensive and bulky.

Would someone suggest he most cost effective technology to build this and where to start?

Thanks!
Kinda impossible nowadays.. Microsoft wait for this time to do housekeeping... If you leave a PC unattended they kick in.. The best way is to set the thing to sleep in power settings...
 

ci139

Active Member
https://msdn.microsoft.com/en-us/library/windows/desktop/aa383614(v=vs.85).aspx
  • ...
  • When the computer enters an idle state. (option : for a specified time . . .)
  • ...
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C:\Windows\system32>shutdown /?
Usage: shutdown [/i | /l | /s | /r | /g | /a | /p | /h | /e | /o] [/hybrid] [/f]

₋₋₋₋[/m \\computer][/t xxx][/d [p|u:]xx:yy [/c "comment"]]

₋₋₋₋No args₋₋₋₋Display help. This is the same as typing /?.
₋₋₋₋/?₋₋₋₋₋₋₋₋ Display help. This is the same as not typing any options.

...
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C:\Windows\system32>systeminfo /fo list

Host Name:₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋
OS Name:₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋ Microsoft Windows 8.1

...
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Last edited:

Meta

New Member
I'm sorry, I should have been more clear. This is for Linux boxes and is meant to reset the computer when it freezes, something these machines experience often enough to be troubling. No software solution will help when the computer is frozen.
 

atferrari

Well-Known Member
https://msdn.microsoft.com/en-us/library/windows/desktop/aa383614(v=vs.85).aspx
  • ...
  • When the computer enters an idle state. (option : for a specified time . . .)
  • ...
________________________________________________________________
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
C:\Windows\system32>shutdown /?
Usage: shutdown [/i | /l | /s | /r | /g | /a | /p | /h | /e | /o] [/hybrid] [/f]

₋₋₋₋[/m \\computer][/t xxx][/d [p|u:]xx:yy [/c "comment"]]

₋₋₋₋No args₋₋₋₋Display help. This is the same as typing /?.
₋₋₋₋/?₋₋₋₋₋₋₋₋ Display help. This is the same as not typing any options.

...
________________________________________________________________
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
C:\Windows\system32>systeminfo /fo list

Host Name:₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋
OS Name:₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋ Microsoft Windows 8.1

...
________________________________________________________________
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
While in the post below, the OP says it won't work for his Linux, could you please what is the definition of "idle" as mentioned in the list of options? The PC doing absolutely nothing is not real, so...
 

Meta

New Member
I'm not looking to reset the box when it is idle, I want it to reset when it is frozen.

I would urge the reader to re-read the original post to review the requirements I had described for an external circuit.
 

AnalogKid

Well-Known Member
Most Helpful Member
A counter that counts in 1-second increments.
Counter is reset to zero any time the HD activity light is lit.
Counter is held at zero while the HD activity light is lit.
If the HD light is out for a long time (1 to 16 seconds), the counter hits a preset value and sends a signal to the computer reset input pin.

Correct?

If so, use a presettable *down* counter. With an up counter, you need a comparator to determine when the counter reaches the trigger value. With a down counter, the trigger value is 0, and the counter's borrow output is decoded internally for you.

Presettable down counter
Signal from HD light drives the LOAD input
1 sec clock to the CLOCK input
BORROW (terminal count) output signal drives motherboard RESET input.

The 74xx168 and 169 are examples of this type of counter. A 555 probably is good enough for the 1 s clock. Because this part has a synchronous load, you'll have to add a monostable to the HD signal to stretch it so is on when the next clock pulse arrives.

ak
 

Meta

New Member
A counter that counts in 1-second increments.
Counter is reset to zero any time the HD activity light is lit.
Counter is held at zero while the HD activity light is lit.
If the HD light is out for a long time (1 to 16 seconds), the counter hits a preset value and sends a signal to the computer reset input pin.

Correct?

...

ak
Correct, except that the reset delay is in minutes, switch setting * 60.

Thank you for the suggestion on the clock and counter. What microcontroller should I be looking at?
 

AnalogKid

Well-Known Member
Most Helpful Member
No uC expressed or implied.

If you can get by with only binary-increment time periods (1 min., 2 min., 4 min., 8 min., etc) rathere than decimal (1 min., 2 min., 3 min., 4 min., etc.) then I recommend a CD4060 for the entire circuit. It is an oscillator and 14 stage binary divider, and has an asynchronous reset. With the right timing components, the high order output bits would be 1, 2, 4, 8 minutes. A dip switch selects which one to send to the computer as the reset signal. The HD signal goes to the 4060 reset.

That is the core circuit. Separate from it are the input and output signal conditioning. For example, the HD activity LED signal might need to be boosted up to logic levels to be recognized by the 4060. Similarly, the 4060 output might not be the correct logic polarity to drive the computer reset. What do you know about these two signals?

ak
 

Meta

New Member
I believe HD LED is 5V. Power LED is also probably 5V and can probably be used to power the circuit. Reset needs a momentary short, not at all sure what voltage is there.
 

AnalogKid

Well-Known Member
Most Helpful Member
The reset input probably expects a switch, so an open-collector to GND should work. Both LEDs are current-limited. If the current limiting resistor is in the wire harness, then the outputs are switched wither to 5V or GND. If the current limiting is done on the computer board, that introduces an inconvenience. Where are the LEDs located?

Where are you located?

ak
 

Meta

New Member
LEDs are usually on a computer case and connect to pins on the motherboard. There is a standard set of pins on the motherboard and a standard set of wires with connectors on cases. The attached picture from a motherboard manual is a fairly typical setup.

I am located in Atlanta, GA.
 

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AnalogKid

Well-Known Member
Most Helpful Member
That doesn't tell me if any of the pins are connected directly to +5V or GND, or if the current limiting resistors are on the motherboard or inline in the wire harness, usually up against the LEDs. With the computer turned off and the wires unplugged, can you measure the resistance from each of the - pins to a ground point?

ak
 
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