Step #1: Materials and ToolsPrevNext
Sound Modules from a Toy
3V Lithium Button Cell Battery
Soldering Iron and Solder
Hot Glue Gun and Hot Glue
Step #2: Select a Sound ModulePrevNext
- The first thing that you need for this project is a good sound module. This can be any small circuit that plays music or sound effects. Toys are a good source for this. If you don't have any sound making toys, you can easily find them at a thrift store. You will probably just need to replace the batteries.
- Ideally you want a sound module that keeps playing the full sound clip even after you release the play button. When you ring a normal desk bell, you quickly tap it. You don't hold it down. So if your sound module stops playing when you release the button, then it won't play long enough to be heard.
- Another option is to use a recordable sound module. This would let you record your own sound clips.
Step #5: Replace the Battery With a Smaller Button Cell BatteryPrevNext
- The battery pack for this toy used two AA batteries. AA's are much to big too fit inside of the bell. So I replaced them with a single 3V lithium button cell battery. To do this I cut the wires from the battery pack. Then I stripped the insulation off the ends. To attach the wires to the button cell battery, I held each wire up to the appropriate side of the battery and wrapped it in electrical tape.
- This will not work for all sound modules. Some circuits require more current than a button cell battery can supply. So you need to test it to make sure that it works. If not, then you can try use AAA batteries if you can get them to fit inside the bell.
Step #6: Remove the Clapper From the Inside of the BellPrevNext
- Next we need to remove the clapper (the part that hits the inside of the bell to make it ring). There are two reasons for this. We don't want the bell to ring when the button is pressed. We also want to make more room inside to bell to put the new parts.
- The clapper is usually attached to the inside supports that hold the bell in place. In order to remove it, you may need to disassemble the bell or you may need to bend the flaps that hold it in place.
- On my bell I was able to just pry the clapper out of the tabs on each side with a screw driver.
Step #7: Decide on the Best Method to Have the Button on the Bell Activate the Play SwitchPrevNext
- Now you need to figure out a way for the button on the bell to activate the play switch on the sound module. Usually the easiest way to do this is to just mount the play switch below the button. That way when the button is pressed, it will hit the play switch and activate the sounds.
- In this case the play switch was very small and it would have been difficult to mount it directly below the button. So instead, I decided to mount the play switch to the inside wall of the base and pressed it with a small piece of plastic that was attached to the button.
- The method that you use will depend on how your bell is constructed.
Step #9: Glue the Play Switch to the Inside Wall of the Bell SupportsPrevNext
- Next I glued the play switch to the inside wall of the bell supports. You want to locate it just below the piece of plastic that you attached to the button. Before gluing it in place, check to make sure that the play switch will be activated when the button is pressed.
- After gluing the play switch in place, you should test it. Press the button a few times to make sure that the sound plays reliably.