It seems like everywhere you go, someone’s cell phone is playing a personalized ringtone. Whether annoying or clever, it’s your call, but inside your home, it’s still the domain of the boring ding-dong. Not for long, however.

If you’ve got a spare MP3 player laying around your home, it’s time to hack your household doorbell system and create your own customized “dingtone.” Just like your cell phone’s ringtone, you can change your dingtone to match the season or your mood. Our seasonal dingtone selection? Bing Crosby’s “I’ll Be Home for Christmas;” natch.

Warning: Make sure the household power is disconnected from your doorbell system before you begin this project.

Don’t knock-knock; dingtone



  • An MP3 player (e.g., Sandisk Sansa Express 1GB, Amazon, #B000MD40N8; $38.72)
  • MP3 player speaker (All Electronics, #NGA-4; $4.35)
  • 9-volt wall adapter (All Electronics, #DCTX-960; $3.75)
  • 78M05 voltage regulator (Digi-Key, #LM78M05CTFS-ND; $0.55)
  • 0.47mF 50-volt electrolytic capacitor (Digi-Key, #493-1885-ND; $0.23)
  • 0.1mF 50-volt electrolytic capacitor (Digi-Key, #P925-ND; $0.18)


1. Rig that MP3 player. Load the song snippet onto the MP3 player. Disconnect the doorbell button from its low- voltage transformer, and connect the wires to the inside of the MP3 player’s “play” button. Replace the transformer with the 9-volt DC wall adapter. Connect the 5-volt voltage regulator’s input to the adapter, and attach its outputs to the USB female cable. Plug the MP3 player into the USB female cable, which will power and charge the player’s battery. Then attach another line from the wall adapter’s output to the MP3 speaker’s battery terminals.

A partially built MP3 player doorbell.
MP3 player: rigged.

2. Take prisoners, and notes. Disassemble your doorbell. Take note of which wires are connected to the transformer (these notes will help you rebuild your doorbell, if you long for a ding-dong, again). Remove the metal plates, electromagnetic coils, and movable plungers from the doorbell. Connect the MP3 speaker and squeeze both the MP3 player and speaker system into the doorbell housing.

3. This postman rings once. Before you reconnect the household power, check all of your wiring with a multimeter. Restore power and program the MP3 player to play a song once (i.e., don’t repeat songs) and don’t power off (i.e., don’t power down or enter “sleep” mode). Run outside and press the doorbell button. Nah, go ahead, press it again and again. Your home now has a personality. It’s own dingtone.

Personalize your dingtones

If you’d like to try your hand at creating a unique dingtone for each regular visitor to your home, then this “mash-up” should get you started:

A person pressing a doorbell on a brick wall near a door.

1. Replace your doorbell button with a Microsoft Fingerprint Reader Model No. 1033 and connect the reader to a dedicated PC (i.e., a PC that can remain on for monitoring your fingerprint “doorbell”).

2. Install and configure Griaule Desktop Identity software.

3. Register Desktop Identity to play an MP3 “dingtone” for each unique fingerprint press. This effort could require some DOS batch programming outside the Desktop Identity application.

This story has been updated. It was originally featured in the December 2007 issue of Popular Science magazine.