Need help with 555 timer circuit - Electronic Circuits Projects Diagrams Free

Good Ole Boy · 5th October 2004, 06:07 PM

Hello,

I am wanting to include a timer circuit camera modification I am making. This will be the first time I have used the 555 IC so be easy on me with the below questions.

All I am wanting to do is delay a relay from closing by triggering the IC to send a single pulse to a NO relay instead of the current direct connection which closes it and complete another circuit immediately. In looking at the pins of the IC, I have read that pin 2 is the trigger, pin 3 is output and pin 4 is the reset.

Does a voltage coming down the line cause the trigger to set or what makes the function of the IC begin?

Am I required to do anything with the other pins since I am only wanting to cause a delay with this IC?

Can I wire the output(pin 3) to the reset (pin 4) so that the output voltage makes the IC reset?

Any suggestions here?

williB · 5th October 2004, 09:21 PM

hello, i have some questions before i can give an answer..

what voltages are we talking about, on the trigger.

how long do you want to delay.. do you want to take time delay pictures?

Good Ole Boy · 6th October 2004, 12:24 AM

We are talking around 5v to the trigger.

No I do not need but a mS or so delay added. What I am trying to accomplish is to allow enough time to pass for the camera to power up before it takes a picture. It only takes a split second to power the camera, but I cant simultaneously accomplish both because its not that quick. Can you help?

Russlk · 6th October 2004, 03:32 AM

The omron G2RL relay has an operate time of 7 mS, so you probably don't need the timer for such a short time delay.

micro571 · 6th October 2004, 03:32 AM

I had a similar question just last week.

What you need to do, is use the 555 timer in monstable mode. there are lots of circuit diagrams on the net for that.

You need a 1-time trigger to get it to start. Check out that solution in this topic http://www.electro-tech-online.com/v...ic.php?t=11561

Goodluck.

Good Ole Boy · 6th October 2004, 04:50 PM

Will the IC refresh since the refresh pin is not used in the solution in that thread?

jrz126 · 6th October 2004, 05:50 PM

do you mean reset instead of refresh? the reset pin is used to restart the timer back to zero. (there is a better discription here http://ourworld.compuserve.com/homep...Bowden/555.htm)

so you would just need to use the monostable/one shot schematic about halfway down the page.
you can either use a switch or send a pulse to the trigger to start the timer. (as shown by the 2 schematics).

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5th October 2004, 06:07 PM	(permalink)
Good Ole Boy	Need help with 555 timer circuit Hello, I am wanting to include a timer circuit camera modification I am making. This will be the first time I have used the 555 IC so be easy on me with the below questions. All I am wanting to do is delay a relay from closing by triggering the IC to send a single pulse to a NO relay instead of the current direct connection which closes it and complete another circuit immediately. In looking at the pins of the IC, I have read that pin 2 is the trigger, pin 3 is output and pin 4 is the reset. Does a voltage coming down the line cause the trigger to set or what makes the function of the IC begin? Am I required to do anything with the other pins since I am only wanting to cause a delay with this IC? Can I wire the output(pin 3) to the reset (pin 4) so that the output voltage makes the IC reset? Any suggestions here?

5th October 2004, 09:21 PM	(permalink)
williB	hello, i have some questions before i can give an answer.. what voltages are we talking about, on the trigger. how long do you want to delay.. do you want to take time delay pictures?

6th October 2004, 12:24 AM	(permalink)
Good Ole Boy	We are talking around 5v to the trigger. No I do not need but a mS or so delay added. What I am trying to accomplish is to allow enough time to pass for the camera to power up before it takes a picture. It only takes a split second to power the camera, but I cant simultaneously accomplish both because its not that quick. Can you help?

6th October 2004, 03:32 AM	(permalink)
Russlk	The omron G2RL relay has an operate time of 7 mS, so you probably don't need the timer for such a short time delay. __________________ see my website: www.geocities.com/russlk

6th October 2004, 03:32 AM	(permalink)
micro571	I had a similar question just last week. What you need to do, is use the 555 timer in monstable mode. there are lots of circuit diagrams on the net for that. You need a 1-time trigger to get it to start. Check out that solution in this topic http://www.electro-tech-online.com/v...ic.php?t=11561 Goodluck.

6th October 2004, 04:50 PM	(permalink)
Good Ole Boy	Will the IC refresh since the refresh pin is not used in the solution in that thread?

6th October 2004, 05:50 PM	(permalink)
jrz126	do you mean reset instead of refresh? the reset pin is used to restart the timer back to zero. (there is a better discription here http://ourworld.compuserve.com/homep...Bowden/555.htm) so you would just need to use the monostable/one shot schematic about halfway down the page. you can either use a switch or send a pulse to the trigger to start the timer. (as shown by the 2 schematics). __________________ Jeff To the optimist, the glass is half full. To the pessimist, the glass is half empty. To the engineer, the glass is twice as big as it needs to be.