Simulate key press right before shutdown

Jake · 09-22-2002, 06:14 AM

Hi guys I got a question....

Im using

Mpxplay
Dos
Via epia mini itx (533mhz)
20x4 Noritake Character VFD
The Opus power supply which has 10 second power off
keyboard controller card from a keyboard hacked to use with custom buttons... mounted on faceplate of player....

ok now here's my question
I need to somehow simulate a key being pressed in under 10 seconds after turning off the car.. because my power supply has a 10seconds that it remains on... because MPXplay has an option to save track position and exit the program to dos from a single key press... so is there a way to simulate a key press or a short between to wires... all i need is to make a two wire contact that is wired to the two pins on the keyboard controller card which represent the key i use to exit and save track position from MPXplay

this is the only thing keeping me from being done.... any and all help is VERY appreciated

Aaron Cake · 09-22-2002, 08:34 AM

A simple 555 timer based circuit connected to whatever triggers your shutdown should work. Then just have it activate a relay that shorts the key contacts of your choice.

Jake · 09-22-2002, 08:51 AM

thanks Aaron Cake I'm a little bit of a newbie... I understand

"have it activate a relay that shorts the key contacts of your choice"

but whats a 555 timer based circuit and what would i hook it up to something on the ignition or something?

thank you so much for your response

Jake

Rob · 09-22-2002, 10:15 AM

A 555 is a multi purpose timer chip, which can do various things, for example you put a signal in and so many seconds later it out puts a signal, or create a series of pulses, depeneding how yous set it up.

They're pretty simple to use as electronics goes, and they're really cheap (rat shack will sell them for a few cents each).

If you have a look at:

http://www.uoguelph.ca/~antoon/gadgets/555/555.html

It should provide you with the basics of how they work and what the do.

If you need any more help let me know.

Rob

ShinkunoNamida · 09-24-2002, 11:40 AM

jake, the opus supply should have different settings for the shut down, i don't know them off hand but i believe they are something like 10s, 10m, 1h

you might not want to leave it on for an hour, but that 10m might be alright.

Jake · 09-26-2002, 12:30 AM

Ok I made a better diagram in photoshop of how I have it hooked up as of now...... my carputers power supply is directly wired to the cars power. So in order for me to turn off my carputer I have been pushing my F10 key which is setup to exit MPXPLAY save last song and track position and then exit to dos and Shut down the computer...

Is what I want to do is wire it up so that all I have to do is turn the car ignition to off position and when I do that the 555 timer should push the F10key so that It shuts down the computer properly... saving the Song and Track position and shutting down.

can anyone help me... all I need is for them to draw or tell me which wires to wire where... cause I really am confused on how to wire it... I follow directions well but Im not electronically gifted.. hehehe

The Red pins on the keyboard controller card are the pins that are connected to the RED button on the carputer faceplate which is my F10 key.

That picture of the 555 timer came from the web site shown at the bottom also link here: http://www.uoguelph.ca/~antoon/gadgets/555/555.html

I know that the opus power supply does the auto shut down after 10 seconds bet that feature just kills the power it doesnt exit MPXplay saving the song and track position like the F10 key does....

Thank You For The Help Everyone

Jake · 09-26-2002, 06:27 AM

bump..... comeone wheres the electronics geniuses... I know there are some on this board.. definaely not me though.... heh

Aaron Cake · 09-26-2002, 08:09 AM

Have you considered searching Google for both "555 timer" and "keyboard hacking"?

I'm a big fan of pointing someone in the right direction, but not giving them the actual answers, forcing them to think.

Jake · 09-26-2002, 08:51 AM

Please..... Help me.......

Jake · 09-29-2002, 01:32 AM

has anyone seen the 555 timer used for what i am trying to do?

If so do they know of a site with some documentation on how to do it?

thanks

cproaudio · 09-30-2002, 01:46 AM

You can goto any DEI alarm dealer and order/buy a 528T pulse timer relay. The timer is adjustable tween 1 and 90 seconds. Set the timer to 1 second. Theres is a neg trigger wire that should be hooked up to the ACC wire. When you turn the key off the ignition, the ACC wire rest at ground therefore triggers the relay. connect the "common" wire (30) to one of the keyboard wire. connect the "normally open" (87)wire to the other keyboard wire. And you're set. This should work the way you wanted. Basically, when you turn the ign off, it triggers the 528T relay for 1 second. It shorts the "common" and "normally open" wires for 1 second.

Jake · 09-30-2002, 07:40 AM

Thanks

about how much those cost? The guy above said the 555 timer is just a few cents at radio shack

cproaudio · 09-30-2002, 11:54 AM

The DEI timer relay is about $25. You only have to hook up 4 maybe 5 wires. Since you said that you're not an electronics genius, hooking up 4 wires shouldnt be that hard. Besides the 555 timer, you also need a relay which could cost about $5. DEI is little more expensive but will save you alot of headache.

jstiltner · 09-30-2002, 10:05 PM

what happens if you hold the f10 key down, will it still shutdown and all...
if so just have a relay that when the key is on, is being held open
(youll need a spdt relay) and when you turn the key off it will fall closed and short f10

this would be equilvilant to you sitting a brick on the f10 button and walking away,

may be somthing to try that is ultra simple

cproaudio · 10-06-2002, 02:30 AM

Quote:

Originally posted by Rob
A 555 is a multi purpose timer chip, which can do various things, for example you put a signal in and so many seconds later it out puts a signal, or create a series of pulses, depeneding how yous set it up.

They're pretty simple to use as electronics goes, and they're really cheap (rat shack will sell them for a few cents each).

If you have a look at:

http://www.uoguelph.ca/~antoon/gadgets/555/555.html

It should provide you with the basics of how they work and what the do.

If you need any more help let me know.

Rob

Rob you seem to be pretty good with the 555 timer. I was wondering if you can wip somthin up for me. My alarm's AUX output is 1 second pulse. I need to shorten that time down to .66 seconds. I need the output from the 555 timer to activate as soon as it sees the input trigger. I have searched the web and have tried to wire up the timer according to the diagram but with no seccess. Do you think you can