Smartify PODB (Plain Old Door Bell)

by expresso2222

Published on September 6, 2015

This project connects a PODB (Plain Old Door Bell) to a separate smart door bell in a remote location (Garden Room). This invention connects the PODB and the smart door bell through two CloudBits and IFTTT.

Duration: 3.5 Hours

How To Make It


Connect to the PODB The first step is to connect the first cloudBit (called "Main House") to the PODB. Here's the circuit. USB Power > Light Sensor> cloudBit ("Main House") You'll need to find the transformer for your PODB and test the voltage using a multimeter. You'll need to find a small lightbulb that can tie into this circuit in series. This way when someone presses the PODB the small lightbulb will light up. The small lightbulb should be positioned over the LittleBits Light Sensor. The LittleBits Light Sensor will send a signal to the cloudBit ("Main House") when it sees the small lightbulb light up. You'll need to find a light tight enclosure so that the only light around this circuit is from the small lightbulb connected to the PODB. You'll also need to tape over the status lights on the LittleBits USB power unit and the cloudBit.

First cloudBit (called "Main House") connected to the PODB


Build the Lego TARDIS This step is optional as you can create another enclosure to hide the LittleBits in your remote location. This project uses Legos to create a Dr. Who TARDIS. Here are the instructions for the Lego TARDIS ( This enclosure hides all the LittleBits electronics and is located in a remote location (Garden Room). I used the LittleBits - Lego connectors. This circuit powers a LittleBits Long LED as well as a LittleBits MP3 player and speaker. The light and speaker are split off of the cloudBit. The circuit in the Lego TARDIS is USB Power > cloudBit (called "Garden Room") > Split branch of the split goes to Pulse > Time Out > Long LED...the other branch of the split goes to MP3 Player > Custom Low Pass Filter (more on that later) > Speaker. Depending on the enclosure you might need some LittleBits Wire to connect all the electronics. For this enclosure - I drilled a hole so that the LittleBits Long LED fits inside the transparent Lego on top of the Lego TARDIS.

Lego TARDIS with LittleBits electronics inside


Low Pass Filter When I first put together the circuit I noticed a buzzing and crackling coming from the LittleBits speaker. After checking the LittleBits community forum I found others with the same problem [are you listening Little Bits? ;^) ]. The issue is that the cloudBit is generating noise (voltage fluctuations) on the VCC line. The following YouTube video shows how to construct a low pass filter to eliminate this noise.  Thanks to Alex Pikkert for the design! You'll need to purchase the LittleBits Proto Module, 100 ohm resistor, and 220 uF capacitor. I purchased the resistor ( and capacitor ( from Digikey.

Low Pass Filter Circuit (necessary to eliminate cloudBit noise on VCC line)

Close-up of Low Pass Filter


Connect Two cloudBits through IFTTT This step will connect the two cloudBits through IFTTT ( You need to get a free account with IFTTT and activate the LittleBits channel. You'll need to create a new IFTTT recipe so that when the first cloudBit ("Main House") gets a signal (via the small bulb and the LittleBits Light Sensor) it will connect to IFTTT and send a signal to the second cloudBit ("Garden Room"). You can also configure IFTTT to send you a text message or email when someone presses the PODB or log each PODB into a Google spreadsheet. IFTTT is very configurable and can link different services together.


Enjoy! Here's the final project - I used the Dr. Who theme music for the MP3 player in the Lego TARDIS and fiddled with the Pulse and Time Out settings so that they matched the length of the Dr. Who theme music when the PODB is pressed.

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