Thanks to Samy for sending in this funny prank project. Check out the build here.
Digital Ding Dong Ditch is a device I created to hack into and ring my best friend’s wireless doorbell whenever I send a text message to the device. The best part of the device is that it causes my friend, without fail, to come outside, find no one, and go back in.
In this project, we’ll learn not only how to create this device, but how to reverse engineer radio frequencies we know nothing about using RTL-SDR (a ~$14 software defined radio), as well as creating hardware and software using Arduino, the Adafruit FONA (GSM/SMS/2G board), an RF (radio frequency) transmitter to transmit custom signals, and even how to reverse engineer a proprietary radio signal we know nothing about!
My best friend Matt (we call him “donr”) mentioned to me the other day that his doorbell was wireless. Incredible!
While he was away from his house, I decided to drive to his house and:
- ring his doorbell a bunch of times, while discovering the radio frequency and modulation used by it
- reverse engineer the signal in order to interpret it
- build a device capable of replaying the doorbell signal (ringing his doorbell), and have it work from long distances by allowing it to receive a special text message to trigger the doorbell
Amazing. Hopefully we’re still be friends after this. I can now ring his doorbell no matter how far away I am from his house, and he will never see my device as it’s hidden across the street wirelessly manipulating his home.
Through this project, I’m going to explain from start to finish how I determined, hacked, reverse engineered, and built each piece and joined them together into this fun project, as well as provide schematics, source code, and explanation from start to finish.
Featured Adafruit Products!
Adafruit FONA – Mini Cellular GSM Breakout – SMA Version – v1: Ring, Ring! Who’s that callin’? It’s your breadboard! Introducing Adafruit FONA MiniGSM, an adorable all-in-one cellular phone module that lets you add voice, text, SMS and data to your project in an adorable little package.
This module measures only 1.75″x1.25″ but packs a surprising amount of technology into it’s little frame. At the heart is a GSM cellular module (we use the latest SIM800) the size of a postage stamp. This module can do just about everything. Read more.
Lithium Ion Polymer Battery – 3.7v 1200mAh: Lithium ion polymer (also known as ‘lipo’ or ‘lipoly’) batteries are thin, light and powerful. The output ranges from 4.2V when completely charged to 3.7V. This battery has a capacity of 1200mAh for a total of about 4.5 Wh. If you need a larger battery, we also have a 2500mAh+ model Read more.