circuit with timer or other way?

There are lots of possible solutions, but you can find a few by going to:

http://rswww.com/

then searching for Multifunction Time Delay Relays.

Unfortunately, because the RS Components site is so crappy, you then have to select "Multifunction Time Delay Relays" from the Categories list on the right.

Good luck.

wow thnx!

What about this one:

maplin timer

Re the Maplin Integrated circuit NE555N Timer - this works fine as a "timing module", but is a low-power semiconductor device for switching DC.

You are switching AC = Alternating Current (The Audio signal) thus a simple relay would be best in your case.

Have fun

thnx for your help!

Silly question now, please forgive my ignorance. I got the 8-pin relays, how do i connect it to the circuit? Whic pin goes where? Do I need anything else or just the realy and directly add it to the existing circuit?

Can you give us the make & part number for what you've got, and tell us a bit about what you're trying to connect it to?

And Please register!

I have a 7555CN (TS555/6CN Low Power timer) and an NE555N.

I have an mp3 player with 1.5V battery, connected to headphones/speakers. For simplicity reasons, headphones/speakers are powered from the mp3 directly. The cable leading from the mp3 to the phones is cut halfway to make a switch. With the circuit closed I need the volume to reduce to zero after x-time (~1sec), so that one has to re-open and re-close the switch placed half-way, if he will listen to another second of sound and so on. I know there is no logic to this, just an experiment I am doing.

Thanks very much for registering (shall I call you Nat?).

This circuit of yours needs a bit of designing. I'm sorry, but I don't have time right now to help much - maybe some of the other guys could step in (?) - I'm off to do some service & repair work this week.

I hope Sparkstation and Hastingselectric are listening!

OK, I'll help. I got a message out of the blue about a relay? I'll reply. "Sparky" should be waking up about now.

Have a safe service.

James

Wow! Thanx for the support so far guys. Just a thought:

What if by closing the circuit, this would send a pulse lasting just ~1sec? I just thought that this would be a different way of approaching it. Or perhaps closing the circuit would charge an electromagnet which would then discharge?? Dunno... I have no idea about this things. I can solder them and put everything together, but I was never good at figuring out how it all works...

OK, a relay will be a little large, but will work. The coil voltage must match your power supply. It must be a timer type relay. Time delay off. If you are able to soldier small electronic parts a 555 chip or similar will be a smaller design. Which do you prefer?

Sparkstation is waking up about now unless he is married to a young hottie. We are working with 1.5 volts. The unit needs to be small, cut off sound at 1 second. Push button and sound returns for one second. Time delay off relay or electronic circuit. These kinds of timer questions make me nervous.

James

the box that will fit in is 25x15x4height(cm). That's the maximum it can hold.

If you are supposed to design / build a circuit using electronics, then the LM-555 RC timer will work. This an old IC but keeps on ticking. The circuit design can be found about everywhere. (Radio Shack if you live in America) This can be used to control the coil of contactors / relays to manage higher power.

Reminds me of the time I had a thief taking tools. The duration of shock was controlled by the timer...oh, never mind, you didn't hear that..

Good luck,

James

Hello again, Guest.

How is your project progressing?

Advise here please.....

it's not progressing.

I am at a standstill.

I think this perhaps is simply impossible to be done.

You're giving up too easily!

This isn't a big problem, honest.

Look at the 555 data sheet, and work out how to make a 1 second one-shot timer (triggered by a toggle switch or push-button), then use the one-shot output to switch a teeny little reed relay to connect the MP3 player output to the headphones/amplifier/speakers or whatever.

Ok I have used this timer kit

The problem is, when someone keeps the start button pressed down, for any reason whatsoever, sound never stops, unless the stop button is pressed (but then again when the stop button is lifted we have the same problem). Is there any kind of switch I can use that does not stay ON, even if it is kept pressed? e.g has to be reset. Or is there any way to activate the STOP button straight after the START button?

I am not sure if I am clear enough so please ask.

I haven't tried this, but it may work!

When you press the button, the top end of the capacitor (= 555 trig) will be pulled down to ground, then will charge up through the 1K resistor.

Let go of the button, & it will stay up.

The capacitor will discharge through the 100K resistor, ready for next time.

It ought to work, looking at the 555 internals.

Good luck, John.

Thnx JohnDG!

One small question: When you say 'let go' the start button, do you mean let it go back to the original position (unpressed) or let it pressed? What would happen if the start button was pressed all the time?

When I say let go, I mean release it. I'm assuming it's a momentary-action pushbutton, i.e. when released, it reverts to the open state. This is how the pushbuttons are shown in the circuit in the Velleman K2579 datasheet.

If you keep it pressed, the 555 will just get the initial low-level START pulse at the trigger input, which will then go back high and stay there, as if the button (in the original circuit) had been pressed very briefly, and released.

There will not be another START pulse until the button is released and pressed again.