I am trying to help my son build a simple beeper circuit as part of the signaling merit badge to send Morse code signals. I built one with an LED but he wants an audio circuit. I have a small 8ohm mini-speaker from Radio Shac, temporary contact button and power supply but nothing else.

If someone could point me to plans for something like this, it would be much appreciated. I've tried searching for plans on my own for well over an hour and either I'm not using the right search keywords or just don't know what I'm doing enough to ask the right question. Any help that anyone can provide would be much appreciated.

Thank you!
Rick

 

Here is a circuit based on the 555 timer chip.

http://home.alphalink.com.au/~parkerp/gateway/noapr98.htm

hgmjr

 

A simpler option might be a piezo buzzer which Radio Shack probably sell. There are two types of piezo, ones that you have to use a circuit like hgmjr posted and ones that make a tone when powered, without any circuitry.

 

I like that one. You could build a 555 version, but a simple piezo or buzzer is simplest.

Are you using a single code key or one of the fancier double paddle code keys? You'll find a lot of HAMs on this site.

 

You'll find a lot of HAMs on this site.

That could be taken in two ways.

The circuit idea is definitely simple, seems to me I saw something like it in an old ARRL publication. Of course the "buzzers" were electromagnets made by winding wire around a nail, a strip of old tin can and an adjustable nut/bolt contact point.

 

I thought about a buzzer as well; however, my son wanted to have a tone that he could control, which adds to the complexity. I'm going to give the 555 circuit posted by hgmjr a try. I especially like how it diagrams for 2 stations possible -- it would be a lot better to use 2 stations and have the sending and receiving scouts in different rooms.

Thanks everyone for your help and pointers!