access-control Archive

Almost three years I published an article detailing how to remotely buzz yourself into an apartment building. In the time since, new technologies have made it even easier to interact with your home remotely. Below, I detail an updated remote door buzzer that works with mobile phones and even Apple Watches. Furthermore, the basic setup is extensible to lighting systems and any other action that can be controlled by a shell script.


The ultimate workflow is simple and is as follows:

  1. On your smartphone or Apple Watch, send a Yo to a custom-created recipient
  2. Your door buzzer will be activated

To achieve this, we’ll be using a custom-made circuit that electronically switches the door buzzer. To control the circuit remotely, we’ll be using a Raspberry Pi home server that will receive casually authenticated signals over the internet sent via the Yo app (

Required Gear

The following items will be used to create your phone-controlled door buzzer:

  • Raspberry Pi — Any Raspberry Pi model should work, but I’m using the Raspberry Pi Model B+. You’ll also need an SD card (micro SD in the case of the B+ model) with at least a few gigs of space, and all gear necessary


…which is to say I don’t.

In the realm of contemporary touch-free interface, RFID and NFC are probably 95% of the pie. They are widely adopted in building access control, contactless payments, mobile-to-mobile sharing, supply chain management, and even hospital patient tracking. For these purposes they are remarkably inexpensive to install and maintain, and the technology is mature. Given these benefits, it is not unreasonable that one should want the convenience of contactless access control without the key fob, chip, or smartphone, and so a small community of DIY RFID-implanters has come into existence.

The notion of implanting an RFID tag is not wholly unreasonable (no so different than many other types of mainstream (implants) and alternative (piercings, tattoos, etc.) invasive body modifications). After all, my two dogs have painlessly carried an RFID chip in the skin between their shoulder blades for years now (for non-pet owners: this is a common practice to allow identification of lost pets). Such purpose-build tags are biologically inert and as RFID does not require a local power source, they do not contain any harmful chemicals and do not radiate unless scanned — they are just a little glass, plastic, metal,