Simple Timer switch (Total NOoB)

Thread Starter

zerocool5878

Joined Jun 12, 2009
9
Hi guys i was hoping someone here could help me out. I am looking to make a switch that will basicly touch to wires together for less then a second and to repeat every 3-8 seconds. Im sure its very simple to do but I will be honest i don't have a clue. I can solder very well and figured i could try it out. I am thinking maybe a 555 timer and a relay or something.

Any help you can offer would be greatly appreciated.
 

thingmaker3

Joined May 16, 2005
5,083
Bill Marsden is working out the details of his 555 tutorial, which will be available here soon. In the mean-time, you can read Tony Van Roon's 555 tutorial: http://www.uoguelph.ca/~antoon/gadgets/555/555.html

The "astable multivibrator" circuit should work well for your needs. Choose values for R1, R2, and C1 which will give a T1 time of "less than a second" and a T1+T2 time of "3 - 8 seconds."

Depending on how much current your relay coil needs, you mght have to drive the relay with a MOSFET or a Darlington Transistor.

Once you can provide more details (relay size or type, operating voltages), we can help!

Welcome to All About Circuits!!
 

Wendy

Joined Mar 24, 2008
23,415
What kind of current and voltage are you talking about using. A 555 can control a relay, but you need to pin the times down a little. Do you want the on time to be ½ seconds? Same thing ThingMaker3 asked, only worded differently.

This makes me think I probably need to include at least one relay project in the 555 chapter, to show how to do it.

Here is the basic information...

 

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Thread Starter

zerocool5878

Joined Jun 12, 2009
9
Not sure but I would like to get the parts from radio shack. Basicly I am trying to open an xbox controller and solder 2 wire onto the "A" button and I just want them to touch for a half second and repeat every 3-5 seconds. I don't have anything except the controller right now but I will go and buy the stuff as soon as I know what I need.
I would like to use a ac wall adaptor for power.

I really appreciate the help.
 
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Thread Starter

zerocool5878

Joined Jun 12, 2009
9
Ok i have this working with just an LED to get the timing right.

Im using a 1M Potentiometer for R1
and a 10k resistor for r2
with a 10uf cap

I need to know how I hook up the relay.

Do I simply disconnect the LED and hook those leads up to a NO relay and then when it would blink the relay would close and touch my wires?

Sorry im sure i sound stupid but this is my first project.

Thanks again
 

Wendy

Joined Mar 24, 2008
23,415
Not sure I understand the question. The schematic I drew shows how the relay is connected to the 555. A relay is a electrically operated switch, the contacts will be in time with the 555. Since I couldn't know what relay you were planning on using I showed a transistor, which increased the drive of the 555.
 
Ok i have this working with just an LED to get the timing right.

Im using a 1M Potentiometer for R1
and a 10k resistor for r2
with a 10uf cap

I need to know how I hook up the relay.

Do I simply disconnect the LED and hook those leads up to a NO relay and then when it would blink the relay would close and touch my wires?

Sorry im sure i sound stupid but this is my first project.

Thanks again
Uhm no it won't work. You need to hook up a transistor then output of transistor will go to relay. You need this because a 555 timer can barely output a LED light. If you plug a relay it would be barely able to switch it. You need to get the extra power juice from a transistor and not from the 555s output.

I also see you want to make a button that will function as a rapid fire button? Am I right? :D
If so I have built something similar in the past using transistors.

Cheers
Franz

Cheers
Franz
 

hgmjr

Joined Jan 28, 2005
9,027
Bill's example circuit in the #3 post in this thread shows the added transistor that has been recommended in order to drive the relay.

hgmjr
 

Thread Starter

zerocool5878

Joined Jun 12, 2009
9
I have this working well without the transistor. I may however need it for my next problem.

I want to control multiple buttons at the same time. So say that I need the "A" button pressed on 3+ different devices. I tryed to hook them all to the relay and it doesnt work. It will only work one at a time. because it is basicly touhing all 6 wires together and somehow messing it up. Is there something I can do to make it touch all three buttons seperatly but at the same time? Would i need a relay for each button? If so i think I may need the transistors as im not sure my current setup will switch 3 or more realys.
 

Wendy

Joined Mar 24, 2008
23,415
It is hard to say, many relays come with multiple contacts, which you can use. I suspect the most you can find is 2 sets, so that means more than one relay.

The transistor is not optional, but you can use one transistor for several relays.
 

Thread Starter

zerocool5878

Joined Jun 12, 2009
9
ok I got a transistor and I hooked it up and it seems to be working but im not sure I hooked it up correctly so if I did it wrong could you tell me. All I know is that it does power 2 relays but I have to get back to the store to get a few more to see if its going to work. For all I know the timer might be doing all the work and the transistor doing nothing.

Anyway I am using a 2N3906-PNP

I connected a wire from pin 3 on the timer to the Base
Then grounded the collector
and hooked the emitter to one side of the relay

The other side of the relay to Power.

I have no way to make a diagram of this because im really new to this stuff and I can barly read the ones you guys put up.

Thanks for your help
 
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