Hi, I have a board that you throw bean bags at and when they go through the hole they hit a paddle I have made. The paddle goes on a standard light switch behind the hole. The paddle has a spring on it so that it will come back to its original position. Then when the switch moves it will activate a bell and light. I would like to have them both be on a timer so when the paddle comes back (it comes back right a way) that the bell and light stay on for about 2 to 3 seconds. I would like to be able to use a 555 timer. Does anybody have a diagram or something that would be helpful? I need to get this done and I would like it to be simple and cheap.

 

connect the switch between pin 2 of the 555 timer and ground, and use a 1K resistor for R1, 10K resistor for R2, and a 400uF capacitor for C. Use the first diagram in this image:

That will give you an on-time of roughly 3 seconds. Hope this helps!
Der Strom

 

DerStrom,
You're giving him values for R1 & R2, but only the astable circuit has an R1 & R2 - which won't do what the OP needs to do.

See the attached schematic; R1 and C1 are the timing components, giving a ~1 second ON time for the buzzer and LED. I used a much larger resistor and smaller capacitor of a standard value. If you really want ~2.2 seconds, increase R1 to 2 MEG.

Ignore V2 and the 2N7002; they simulate the closure of the switch for simulation purposes.

R3 and R4 were selected for a power supply of 10v. Since our OP has not stated what they are intending for use as a supply, they will do for the moment; but will be OK for ~6v to ~10v.

 

DerStrom,
You're giving him values for R1 & R2, but only the astable circuit has an R1 & R2 - which won't do what the OP needs to do.

Oh, I'm terribly sorry about that! Thank you very much for pointing that out, SgtWookie!

DS

 

Hey thanks for the info I'll see what I can come up with.

 

I was wondering if you could post a pic of your board with the paddle. I was interested in doing something similar but was considering using some kind of IR sensor to know if the beanbag has gone through the hole. Seems like unless you have a very weak spring the paddle might prevent some of the bags from falling through the hole if it's just creeping over the edge of the hole.

 

I know what you mean. I happen to have a very weak spring and the paddle is made out of steal, and it has a hole in it at the top that the spring is mounted to and that way I do not have to worry about the beanbags messing it up. And no I can not post a picture because I do not have a camera at the currant time. sorry about that. The light switch that I'm using has a lot of travel so that beanbags have to hit it pretty hard. I like your idea. Also the paddle is fairly big. So I do not have to worry about the beanbags just making it through. Enjoy!