help with electronic delay
Maz, Wed Apr 26 2006, 02:55AMi am trying to build a pc case with power switches that work like touch lamps. this is difficult because vital components need to be on when the computer is and i wish to have 3 switches.
with different functions
one for main power:
i want this to have no delay when turning on the system, but a 3 second delay before the power is switched
one for the fans:
i want a three second turn-on/off
and finally one for the lights:
i want to "voob" them on
an easy thing to do with a LM324 ic but i want them to stay on after the current is high.
then turn off the same way.
Re: help with electronic delay
..., Wed Apr 26 2006, 03:27AM
to make a delay you just use a 555. You hook the reset up to the switch, and wire it as monostable. Since it triggers on falling edge, you need to use a pullup on the switch.
I supposse you could create the 'voob' by taking putting a mosfet across the cap in the 555, and driving the led off that... You could use a resistave divider (using like 1M of resistance) to get the right fading effect...
Is there anything the 555 can't do
Or an even easier route would to get mikrobasic (or whatever) and burn a pic12f675 to do it...
Have fun!
..., Wed Apr 26 2006, 03:27AM
to make a delay you just use a 555. You hook the reset up to the switch, and wire it as monostable. Since it triggers on falling edge, you need to use a pullup on the switch.
I supposse you could create the 'voob' by taking putting a mosfet across the cap in the 555, and driving the led off that... You could use a resistave divider (using like 1M of resistance) to get the right fading effect...
Is there anything the 555 can't do
Or an even easier route would to get mikrobasic (or whatever) and burn a pic12f675 to do it...
Have fun!
Re: help with electronic delay
Maz, Sat Apr 29 2006, 01:39AM
what do you mean a pullup?
Once i trigger the 555, i can have it run for 1.5 secs.
the output from the 555 can run a transistor,
so i can power my ic(lm324) for its rise time (1.5s) and "voob" the LED on
but how could i keep it on
i could run another 555 independently from the premade system, and delay its function until 1.5s and then become the led's power source.
but how do you make a delay (original question), so i can run it afterwards.
can i even run a 555 continuously?
or is there better alternatives?
Maz, Sat Apr 29 2006, 01:39AM
what do you mean a pullup?
Once i trigger the 555, i can have it run for 1.5 secs.
the output from the 555 can run a transistor,
so i can power my ic(lm324) for its rise time (1.5s) and "voob" the LED on
but how could i keep it on
i could run another 555 independently from the premade system, and delay its function until 1.5s and then become the led's power source.
but how do you make a delay (original question), so i can run it afterwards.
can i even run a 555 continuously?
or is there better alternatives?
Re: help with electronic delay
Jim, Sat Apr 29 2006, 04:42PM
voob.
How about "fade on?"
Jim, Sat Apr 29 2006, 04:42PM
voob.
How about "fade on?"
Re: help with electronic delay
Maz, Sun Apr 30 2006, 02:19AM
well that would be way too technical. especially I'm mostly asking for help from engineers when I'm a novice. i really don't feel like being swamped in the engineer dialect.
but i see your point.
Maz, Sun Apr 30 2006, 02:19AM
well that would be way too technical. especially I'm mostly asking for help from engineers when I'm a novice. i really don't feel like being swamped in the engineer dialect.
but i see your point.
Re: help with electronic delay
HV Enthusiast, Sun Apr 30 2006, 03:21AM
What you are asking for is commonly known as power sequencing. You might have some luck finding a dedicated sequencing chip that has programmable delays (either digital or via RC) that you may use. Also, a microcontroller is a perfect solution for what you are asking, such as a PIC.
HV Enthusiast, Sun Apr 30 2006, 03:21AM
What you are asking for is commonly known as power sequencing. You might have some luck finding a dedicated sequencing chip that has programmable delays (either digital or via RC) that you may use. Also, a microcontroller is a perfect solution for what you are asking, such as a PIC.
Re: help with electronic delay
Maz, Sun Apr 30 2006, 03:36AM
while the fade on would be nice, it is not nessicary.
for this i must use a momentary switch (qprox qt110) so is there anyway i could make the momentary into a permenantly on switch until i tap it off again?
pic (from when i was going to buy one) are really expensive and i would need a programming kit. i dont feel like spending 100+ dollars for a light switch.
Maz, Sun Apr 30 2006, 03:36AM
while the fade on would be nice, it is not nessicary.
for this i must use a momentary switch (qprox qt110) so is there anyway i could make the momentary into a permenantly on switch until i tap it off again?
pic (from when i was going to buy one) are really expensive and i would need a programming kit. i dont feel like spending 100+ dollars for a light switch.
Re: help with electronic delay
Wolfram, Sun Apr 30 2006, 07:34AM
Small PICs can cost around a dollar and a programmer can be made with a couple of resistors.
Wolfram, Sun Apr 30 2006, 07:34AM
Small PICs can cost around a dollar and a programmer can be made with a couple of resistors.
Re: help with electronic delay
Conundrum, Sun Apr 30 2006, 03:12PM
Hi,
Other possibility is a simple R-C delay circuit with a transistor.
switch---resistor---capacitor across base-emitter junction.
-A
Conundrum, Sun Apr 30 2006, 03:12PM
Hi,
Other possibility is a simple R-C delay circuit with a transistor.
switch---resistor---capacitor across base-emitter junction.
-A
Re: help with electronic delay
Maz, Mon May 01 2006, 01:10AM
Conundrum: thank you for your help! the delay would work by using a resistor to bleed into the capacitor.filling it until it reaches a high enough voltage to trigger the transistor.
am i correct?
anders: sorry, i got the value (cost) from an old magazine that sold it as a kit. the price was 129.00$ everything pre-made.
Maz, Mon May 01 2006, 01:10AM
Conundrum: thank you for your help! the delay would work by using a resistor to bleed into the capacitor.filling it until it reaches a high enough voltage to trigger the transistor.
am i correct?
anders: sorry, i got the value (cost) from an old magazine that sold it as a kit. the price was 129.00$ everything pre-made.
Re: help with electronic delay
kell, Thu May 25 2006, 08:46PM
I'll post an example of an RC delay circuit, just because it so happens I drew one up last night in notepad. This is for an "autopurge" in a waste vegetable oil conversion of a diesel engine. When you turn off the ignition switch, the engine continues to run for a time of a few seconds to a minute or two (that you can set with a potentiometer). This runs in conjunction with a solenoid and valve that changes the fuel from wvo to diesel when you turn off the ignition key. During the run-on time, the conventional diesel fuel purges the wvo from the engine so it doesn't gum up when it gets cold.
This circuit isn't exactly what you asked for. I posted it just to demonstrate the principle.
kell, Thu May 25 2006, 08:46PM
I'll post an example of an RC delay circuit, just because it so happens I drew one up last night in notepad. This is for an "autopurge" in a waste vegetable oil conversion of a diesel engine. When you turn off the ignition switch, the engine continues to run for a time of a few seconds to a minute or two (that you can set with a potentiometer). This runs in conjunction with a solenoid and valve that changes the fuel from wvo to diesel when you turn off the ignition key. During the run-on time, the conventional diesel fuel purges the wvo from the engine so it doesn't gum up when it gets cold.
12 volts
from
battery
|
__|__
12 volts from | |
ignition switch |relay|------output
| |_____|
| common |
| diode _|D
| (e.g. 1N4001) | n-channel
'----1K resistor--------->|------+-------+-------+------|| mosfet
| | | |_ (e.g. IRF540)
| | | |S
100 uF ----- | 15 volt |
electrolytic----- | zener diode |
capacitor | potentiometer| |
| 50 or 100K | |
| | | |
| | | |
| | | |
'---+---+-------+---------'
|
|
ground This circuit isn't exactly what you asked for. I posted it just to demonstrate the principle.
Re: help with electronic delay
Wolfram, Thu May 25 2006, 09:05PM
What circuit are you using for the voobing?
Wolfram, Thu May 25 2006, 09:05PM
What circuit are you using for the voobing?
Re: help with electronic delay
Maz, Sun May 28 2006, 02:32PM
this circuit is the one for it. but unless there is a better one...
Maz, Sun May 28 2006, 02:32PM
this circuit is the one for it. but unless there is a better one...
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