Programmer

About Esper

Heavily inspired by the Pi-Hole, this project aims to bring network wide ad-blocking to another popular device popular among makers and hobbyists, the ESP32.

What is DNS?

Commonly referred to as the "phone book for the internet", the DNS protocol is how devices map human readable urls like google.com or facebook.com into IP addresses that the device can use.

How does Esper block ads?

Just like the Pi-Hole, Esper acts as a DNS server for devices. When sent a DNS query, Esper will read the url the device is requesting, then decide to block the request by returning 0.0.0.0 or forward the request on to a real DNS server.

Differences between Pi-hole and Esper

The biggest, and most obvious difference is the hardware these projects run on. Pi-hole aims to be available on any Linux powered hardware, while Esper is an ESP32 specific project. Due to being run on a microcontroller, Esper is much more limited in it's capabilities and is therefore much more minimal in it's design.

Why choose Esper instead of Pi-hole?

Choose whatever one suits you! If you like tinkering with hardware, and do not have much experience with the Raspberry Pi/Linux ecosystem, setting up the Esper software on an ESP32 dev board might be an interesting project. And while Esper may not be nearly as powerful as a Raspberry Pi, DNS protocol is very lightweight in nature. Unless you are in a household with 10+ people that are always online you will likely never going to need more computing power than a microcontroller can provide.

At the same time, if you have no problem using a shell and Linux environment, the Pi-hole is a much more feature rich and powerful piece of software that is a joy to use.

How can I get an Esper?

The easiest way, is to purchase a pre-made one from the Tindie store.

If you have some ESP32 development boards collecting dust, it will work on those too! (Just follow the instructions here!)

DISCLAIMER: It is heavily recommended to use a device with ethernet. Even the best Wifi will significantly increase latency and decrease reliability compared to a good copper connection.

If you want to try you hand an making an Esper from scratch, the repository contains all the schematic, pcb, and enclosure files needed to build one yourself.

Reprogramming Esper

Do you like the Esper hardware, but want to use it for something other than ad-blocking? Great! The Esper hardware is completely reprogrammable and includes an on-board USB-UART converter, no extra programmers are needed!

Esper Development

Tools Used

• KiCAD - EDA tool used to design PCB
• FreeCAD - 3D modeling tool for designing enclosure
• ESP-IDF - Contains ESP32 API and build tools for firmware development
• Python 3.7 - Scripts to glue everything together

Directory Structure

├── hardware                    # Hardware root directory
│   ├── custom components           # Custom KiCad component files
│   ├── enclosure                   # FreeCAD project and STL files for enclosure
│   ├── product                     # KiCad projects for Esper
│   │   ├── usb-programmable        	# Includes CP2102 for easy usb programming
│   │   └── jtag-header             	# 10-pin header for JTAG & UART, meant to be used with programmer
│   └── programmer                  # KiCad project for programmer/debugger
└── software                    # Software root directory
    ├── firmware                    # ESP-IDF project that contains all code for Esper
    ├── scripts                     # Scripts used in build process and testing
    └── website                     # For website development, contains symbolic links to HTML files