Anyone knowing electronics please help me..

[ajaybc]

I have a P4 machne with Intel original 845GLVA motherboard which doesn't
support automatic booting.Please anyone knowing electronics please send me the circuit of a device that can boot the computer at a preset time.
PLEASE............................................ ....................................

[ranjan2001]

I dont know much about automatic booting topic but once someone discussed here that a compro TV tuner card had preset time to boot the comp & record the show & then shutdown & record at another time, so getting a 2000/- card might help giving u both capabilities.

Search for such cards, that might help.
I wonder what could else be this useful apart from TV recording, why would u want ur comp to boot automatically.

[infra_red_dude]

Originally Posted by ajaybc

I have a P4 machne with Intel original 845GLVA motherboard which doesn't
support automatic booting.Please anyone knowing electronics please send me the circuit of a device that can boot the computer at a preset time.
PLEASE............................................ ....................................

unless you know how the power supply is routed on the mobo its not possible to interface a separate circuit. wid the advent of acpi and atx power supply its not like the earlier at psu where simply turning on the power switch will turn on the system (so to make a circuit like this you cud employ the IC 555 timer). unless the mobo supports it and has options in bios its not possible.

[ranjan2001]

MY BIOS support this feature but I have not ever used it, actually never needed it.

IF ur sole purpose is to start download (rather booting) at a particular time (unlimited bandwidth at night) then u r trying to reinvent the wheel............no need to do that, there are 100s of software which will do that for you, they can stop all internet downlaod & start download as per your preset time, so u dont have to wake up at odd hrs.

U can control ur bandwidth,
u can control what all application are allowed to connect
u can control the start time & end time.
IN gud old days of dial up connection I had such software...........let me see if I can find out that for you......................but I am sure there r plenty of them now.

Make another post in software forum asking about ur actual requirements & some member can surely help u.

[iMav]

@infra i hink its rather easy ... the power button conx on the cabinet can be easily trigerred by an external timer ckt and that wud be rather easy to setup

so the setup wud be like the power button conx on the cabinet wud be trigerred by a 555

[csczero]

Putting PC on STAND BY with Windows schedular would do the trick

[infra_red_dude]

yes imav, you can then you'll need a two way switch to shift from the timer to the power button. its not difficult.. but hafing support in bios is always a better and safer option.

[ajaybc]

My plan is this:see image attachment
Will u please tell me how to use that timer bcoz iam an absolute zero in electronics.please send me the circuit drawing

[Pathik]

i hav very limited knowledge of electronics... but u can use a software that can access ur cmos timer and accordingly switch on/off ur computer..

[infra_red_dude]

ajay the problem wid ur circuit is that the power button is no longer the kinda one shown by you. so you can't haf the timer circuit in parallel. you'll hafta use a two way switch for that.

things required to set the timer will be a variac (variable capacitor) and/or a rheostat (variable resistor). the time duration is calculated by this formula, if i remember rite (Been 3 years since i studied used it!! )
T = 1.1RC where t is time in secs, r is the resistance in ohms and c is the capacitance in farads. C is chosen to some viable value then R is adjusted accordingly for a required value of t. but then this circuit will need a separate power supply of its own and one thing to remember is that the ic555 needs to be operated in the monostable mode.

man! this is interesting. we can haf a small project on this i'll get back in sometime. gotta go out for some work. meanwhile it'd be good to see people pouring in the ideas

[iMav]

infra how do u include a clock in it ...

[infra_red_dude]

you don't include a clock! you set the timer from the values of potentiometer and the capacitor!

[ajaybc]

I want the device somewhat like an alarm clock where u can set the time for booting just like u do for setting alarms.It then wud be very convenient to use.
The following text may be idiotic.IF IT IS,IT IS OUT OF MY IGNORANCE OF ELECTRONICS

Can we use the same mechanism like in digital alarm clock?
i.e wen the preset time comes it sends a small current to the buzzer which make the noise.The same thing with a little diff can be applied here.
That is wen the preset time comes the circuit is complete(the two wires of the power button is shorted) for a second or two and the computer boots up.
If it is possible please send me the circuit diagram.I can get an old alarm clock and we can make necessary changes for this purpose.

Please ...Please help me.......

[CadCrazy]

Search here
http://www.electronicsforu.com

[ranjan2001]

Thats gud source for finding ur kind of circuits here the link to that page http://www.electronicsforu.com/electronicsforu/lab/

look at no. 40 & 170
http://www.electronicsforu.com/efyli...dec99/self.gif

[infra_red_dude]

this is getting interesting! ajay, you'll need a relay to complete the circuit as the current is jus too small and finding a relay that operates at such a low current value is a task too

all we want to build here is a simple timed trigger circuit. the timer is the ic555 and the triggering device is a small relay (an electromechanical triggering device). however, the time mebbe restricted to minutes unless we use some not so common potentiometers and capacitors.

[zyberboy]

Originally Posted by ajaybc

The following text may be idiotic.IF IT IS,IT IS OUT OF MY IGNORANCE OF ELECTRONICS

Can we use the same mechanism like in digital alarm clock?
i.e wen the preset time comes it sends a small current to the buzzer which make the noise.The same thing with a little diff can be applied here.
That is wen the preset time comes the circuit is complete(the two wires of the power button is shorted) for a second or two and the computer boots up.
If it is possible please send me the circuit diagram.I can get an old alarm clock and we can make necessary changes for this purpose.

Please ...Please help me.......

Yeah this will do the trick u can make use of that voltage coming to the buzzer, u only need a small amplifier to increase the current to drive a relay.This will make a cheap timer clock with good accuracy.

[ajaybc]

Originally Posted by cyberboy_kerala

Yeah this will do the trick u can make use of that voltage coming to the buzzer, u only need a small amplifier to increase the current to drive a relay.This will make a cheap timer clock with good accuracy.

Will any one give me the circuit diagram for the modifications I should make in the alarm clock,like he said with amplifier.
Please............................................ ..............

I saw somewat similar circuits in electronicsforyou.com but it requires lots of modifications
If any one can tell me how to modify an alarm clock for this I wud be greatful

[infra_red_dude]

@ajay
i went thru the circuit and it'll work. but i haf one doubt regarding the relay. in that circuit the relay will remain on for the entire period till the circuit is manually switched off. when connected to the computer this means that the two pins will be shorted untill its turned off. however the method applied to power on modern system is that there's a momentary short of the two pins on the mobo. as soon as it powers on the switch is released and they are no longer shorted. will there be any harm to the system if the two pins are shorted for long? that is my question now.

[ajaybc]

Regarding the circuit in http://www.electronicsforu.com/elect...=Time%20Switch .Is there any way to shorten the shorting time of the pins?
If it is shortened for long the system will turn off i think.Haven't tried yet.

If there is no prblm with the length of shortening then that is the solution.

[infra_red_dude]

that circuit is designed to behave like that. imagine what will happen if the time is reduced? the device will switch off and hence the whole circuit becomes useless. we need a pulse for a very short duration (in the order of milliseconds) for the system to boot up. that circuit can't be used unless the computer doesn't haf any problem while the poweron pins are kept shorted. now the question is how can we test if this causes any probs or not?

[iMav]

Originally Posted by cyberboy_kerala

Yeah this will do the trick u can make use of that voltage coming to the buzzer, u only need a small amplifier to increase the current to drive a relay.This will make a cheap timer clock with good accuracy.

exactly what i had in mind instead of the buzzer we connect the power wire of the cabinet power switch

[ajaybc]

Does any one know whether there is any problem in keeping the poweron button in the CPU pressed?

[ranjan2001]

I dont think so................why not try it on a old comp if u have any.
Power button is to short the circuit & ones its short & remain shorted nothing would happen, re shorting it would shut down.

[iMav]

@ajay: there are circuits for what u said but i cant remmber which 1s but there are various ways for that ....il see if i can dig 1 up .... for now i think we could use a gate even if it is high it will generate a single pulse and wont be affected of what happens next

[infra_red_dude]

how will a gate convert a cont. high to a pulse, imav??? output duration will be like the input duration. we need to generate a pulse at a specific interval to trigger a relay which in turn shorts the power terminals momentarily to turn on the system. there are circuits. lemme also try to search for them.

[iMav]

arre 1 0 wala gate ... hai yaar waisa circuit padha hai par abhi yaad nahi ...

current is coming and it will stay high that is at logic 1 so the cpu will only get a continuous 1

[infra_red_dude]

1 0 wala gate? not gate? hey bhai.. no gate will generate pulses.. rather a latch (single input flip flop made of not gates) will hold the value for long. and thats exactly opposite to what we want. yeah i know there are pulse generating circuits but they are too complex to build. keep searching imav... i too will.. hope we stumble upon something simple...

[iMav]

arre sorry flip flop

[Pathik]

Originally Posted by infra_red_dude

@ajay
i went thru the circuit and it'll work. but i haf one doubt regarding the relay. in that circuit the relay will remain on for the entire period till the circuit is manually switched off. when connected to the computer this means that the two pins will be shorted untill its turned off. however the method applied to power on modern system is that there's a momentary short of the two pins on the mobo. as soon as it powers on the switch is released and they are no longer shorted. will there be any harm to the system if the two pins are shorted for long? that is my question now.

Afaik in most systems the system boots up only wen the power button is pressed and then released.. Not if the power button is kept pressed.. Btw aint there any ic wich can communicate with the cmos??