Thread: help to design a timer circuit

look for a latching relay, like this one:

http://cgi.ebay.com/ws/eBayISAPI.dll...sPageName=WDVW

I cant remember the model number of the DEI component I am using, but its similar to this one. basically, I can set mine from 1-60 seconds, or completely latching. So, rather than hook remote turn on (or ACC) direct to the amplifeirs, I can use either of those two to hit the relay. You might need to build a pulse circuit, that will take a constant signal and make a pulse out of it, depending on how the relay reacts to a constant input to the coil.

this will set the timer relay off, shorting the switch for 20 seconds, which is what youll have set it for.

the switch ouput would turn on a bosch relay. input for the pole of the bosch relay would be acc or amp turn on, whatever source you are using to turn the amps on. the pole will be the amp itself, but use the pole that is normally closed

when the car is off or radio is off, the bosche relay is closed and the circuit to amp turn on is complete, but the lead is dead, so the amplifiers are dead.

when the car is on or teh radio on for the first time, the wire is live, so the amp *should* go on, but it also triggers the latching relay, which turns the bosche relay off for 20 seconds. or 5 seconds. or 1 second, or indefinitely, whatever you want to set it at.

at the and of this time, the latching relay shuts down, the bosche relay clicks of,f and your 12 volt source is allowed to flow to the amplifier.

done!

Originally Posted by CdRsKuLL

I'm after a 20 second timer, this is going to be used to delay the turn on of my amp. I will be using the 12v line from my opus to trigger the timer, and the ACC line from the car as the main feed to my amp.. so really a relay and something that waits for 20sec's before it passes the signal.. I dont know much about electronic's.. but i'm ok with a soldering iron.. please help

cheers

CdR

Here is the circuit I used: (similar in concept)


My computer is set to go into standby when key is turned off (set in power options), then if the vehicle is not started back up in an hour the system goes into hibernation (set in power options)

The first timer (standby) relay is set to send a negative trigger (to latching relay) after 3 seconds (the time it takes for audio signal to resume coming out of standby) and a positive trigger 1 second after key is turned off

The second timer (hibernate) relay is set to send a negative trigger after 20 seconds (the time it takes for audio signal to resume coming out of hibernation) and a positive trigger 1 second after key is turned off

If there was a low voltage turn on circuit (ie. line level voltage not amp level 4.5v or greater) then all of this would not be necessary.
I've searched and been unable to find one.

From Mancunia eh?? Where abouts?? im in Wigan, anynews of NorthWest meet?

nrls2000, that's cool! But I don't totally get it. You have power switch set to standby, and hibernate set to 1 hour. How does it go from standby to hibernate? Does it start back up, then instantly know it's been idle for an hour or that the key is not in the ignition?

Originally Posted by OriginalNick2

From Mancunia eh?? Where abouts?? im in Wigan, anynews of NorthWest meet?

I'm in Nr Chorley. I wish Scan would stock some Xenarc screens and put them on today only!!!!

Originally Posted by Curiosity

nrls2000, that's cool! But I don't totally get it. You have power switch set to standby, and hibernate set to 1 hour. How does it go from standby to hibernate? Does it start back up, then instantly know it's been idle for an hour or that the key is not in the ignition?

Scenario 1:
I go to the gas station. When I turn the car off the computer goes into standby (in standby the psu remains on during standby so any four pin power connector will still have 12v+, common, 5v+, common). The psu energizes the bosch relay sending whatever signal is present from the standby timer relay. After 5 min (done pumping gas)...turn the car on...as the computer resumes from standby (3 sec) both timer relays are triggered...however because of the bosch relay the audio system turns on with the "standby timer" (3 sec).

Scenario 2:
Same as before...I go to the gas station. When I turn the car off the computer goes into standby (in standby the psu remains on during standby so any four pin power connector will still have 12v+, common, 5v+, common). The psu energizes the bosch relay sending whatever signal is present from the standby timer relay. However, I meet a friend in the gas station and we talk for more than an hour. At the one hour mark the computer automatically wakes up and hibernates (in hibernate the psu shuts down completely...de-energizing the bosch relay sending whatever signal is present from the hibernate timer). All told, 1.5 hours later I turn my car back on...as the computer resumes from hibernate (20 sec) both timer relays are triggered...however because of the bosch relay the audio system turns with the hibernate timer (20 sec)

In a nutshell the audio system "knows" (because of the bosch relay) if the computer will resume in 3sec (standby) or 20sec (hibernate)

That's an excellent design. It's giving me some strange ideas and I think only one timer is needed if you're not worried about thump. I'm using a 555 as a voltage controlled relay UPS thingy, and could add another one as a timer but want to trigger it by power going low. Doesn't anything turn off in standby? I already have software that detects ACC, IGN, engine running, and can hibernate or standby on that logic and know what it just came out of. I think I just want to make that or the PC powering down start the timer which will probably turn out all complicated and wind up doing what yours does, but oh well.

Originally Posted by Curiosity

Doesn't anything turn off in standby?

USB devices shut down, HDD, DVD drive.

I believe you can program usb devices to either shutdown or not.

My system pulls 16amps at idle and 6amps on standby...so, something is turning off.

Originally Posted by Curiosity

I think only one timer is needed if you're not worried about thump.

The timers are only needed for audio system turn on and off. Minus the constant to momentary relay the computer does the rest in the "power options" settings

Using xp, go to control panel/power options

select the hibernation tab and check "enable hibernation" hit apply

go to the advance tab choose the "standby" option in the drop down menu for "when I press the power button on my computer:" then you can wire a relay circuit to pulse the shut down wires

then go to the power schemes tab in the drop down menu for hibernate select whatever time frame you are comfortable with from "after 1 min" to "after 6 hours"