Introduction: SMS Doorbell + Answering Machine

About: littleBits makes an open-source library of electronic modules that snap together with tiny magnets for prototyping, learning, and fun. littleBits consists of tiny circuit-boards with specific functions enginee…

Receive a text notification when someone rings your doorbell. Respond by playing back a recording to let them know you are on your way. Elevator music anyone?!

Whether you are in the backyard gardening, over at the neighbor’s house, or listening to music at full blast, you will always know when someone is at your door. Install this littleBits doorbell outside your home, and never miss a ring.

How it works:

When pressed, the button module on the Doorbell Answering Machine sends a signal through the cloudBit to IFTTT, which is set (via the SMS channel) to send you a text message [i.e. Knock knock! Someone is at the door]. IFTTT (If This Then That) is a service that lets you connect to different web apps through simple conditional statements. With a second IFTTT recipe, you can respond to the text message [i.e. #onmyway]. This will trigger the cloudBit in the Doorbell Answering Machine and activate a sound clip on the mp3 player to play out on synth speaker.

Step 1: Set Up Your CloudBit If You Haven’t Done So Already.

Step 2: Connect Your Circuit

USB power + button + bright LED + cloudBit + mp3 player + speaker.

We held our circuit together with littleBits adhesive shoes. Note: you could also add a split to this circuit in order to better configure it for your build.

Step 3: Load Audio Files Onto the Mp3 Player.

Remove the SD card from the base of the board by pressing it in. It should pop out :) Place the SD card in an SD card adapter, pop it into your computer, and add any .mp3 files you like. When you are done, place the SD card back in the mp3 player. Make sure it clicks in place.

Step 4: Set the Mp3 Player to Whichever Mode You Like.

If you only want one song/sound clip to play back to your visitors, we suggest “once mode”. If you want different sound clips to play back to your visitors, try “next” mode. Quickly test the mp3 player by removing the cloudBit from the original circuit so that is looks like this: power + button + mp3 player + speaker. The button module in this case acts just as the cloudBit will in the final setup. Press the button to play your sound files. If you are satisfied with the interaction, add the cloudBit back in.

Step 5: Create an Account on IFTTT (If This Then That) and Activate the LittleBits Channel.

Step 6: ​Set Up the Text Messaging Using IFTTT’s SMS Channel.

You will need to create two recipes - one that sends you a text message when someone rings your doorbell and another that plays a sound clip for your guest when you text back. See how we set up our recipes:


If button is pressed on SMS Doorbell, then send me a text message

When I text #OnMyWay, then activate elevator music on my SMS Doorbell

Step 7: Build Your Custom Doorbell

Refer to our previous SMS Doorbell project to see how we put together the housing for the circuit.

Step 8: Test It Out and Put It to Use!