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Picture of Raspberry Pi Zero Wifi Access Point With a Custom PCB Antenna

What are we making?

The title of this tutorial has lots of technical terms in it. Let's break it down.

What is a Raspberry Pi Zero (Rπ0)? A Raspberry Pi Zero is a tiny computer. It is the smaller version of the Raspberry Pi single board computer, and it can fit in a 30mm by 65mm by 5mm box. In addition to its small size, it is very inexpensive and very low power. It is also powerful enough to run a full Linux based operating system, Raspbian. As with any other computer, you can use the Rπ0 to browse the web, play games, use office tools, write software, and so on. This tutorial uses the Raspberry Pi Zero Model W, which has a built in wifi adapter.

What is a wifi adapter? If you want to use wifi to connect your cellphone, tablet, or laptop to the internet, your device needs a wifi adapter. A wifi adapter contains circuitry and an antenna. It converts data signals to and from electromagnetic waves with frequency near, for example, 2.4 GHz. Most cellphones, tablets, and laptops contain a built in wifi adapter. However, you can also purchase an external wifi adapter which connects to a computer via USB. In this project, we use both the internal wifi adapter of the Rπ0 as well as an external wifi adapter.

What is a wifi access point? Multiple cellphones, tablets, or computers can communicate wirelessly with a single wifi access point, and data from these devices is transferred through the access point to the internet. In this project, the Rπ0 is the wifi access point. Why would you want your own wifi access point? Devices need to be within around 100 meters of an access point to communicate. Suppose there is a public wifi access point in the center of a library. Anyone with a laptop within that distance can use the access point to wirelessly get online. What if you want access in the park next to the library, 200 meters away? You can put a new access point at the edge of the library's property, 100 m from the first access point. Then, anyone with a laptop within 100 m of that new access point also can get online. Within limits of available bandwidth, these access points can be chained together to spread internet access over a wider area.

What is a custom Printed Circuit Board (PCB)? A PCB is a circuit constructed by depositing layers of material on an insulating board. Copper is patterned in desired locations to form wires, and holes are drilled where components will be placed. Custom PCBs are designed using specialized software. For this project, a custom PCB was designed using the open source KiCad software. The design was then sent to a manufacturer to be produced. Designing and ordering a custom PCB is neither expensive nor time consuming. The steps are detailed below. If you lay out a PCB using software and have it manufactured, you get a circuit that is durable, precisely manufactured, and designed to your exact specifications. In this project, we use a custom PCB to make a wifi antenna.

What is an antenna? The antenna is the part of the wifi access point hardware which converts signals to and from electromagnetic radiation. Many antennas can transmit and receive signals equally well from all directions. Other antennas are directional, operating much better along a particular direction. In this project, we chose to use a directional antenna. When a directional antenna transmits a signal, it focuses the energy in a particular direction so, all else equal, a well aligned directional antenna can communicate over a longer distance than one that is not directional. This Instructable was inspired by another Instructable that made a directional wifi antenna out of (literally) paperclips and popsicle sticks. That Instructable contained a pattern for a wifi Yagi antenna, and our antenna is made from that pattern with slight modifications. A Yagi antenna, also called Yagi-Uda antenna, is a type of directional antenna originally designed in 1926. Another great source of antenna designs, as well as other information about antennas, is the ARRL antenna book.

While some people access the internet multiple times a day, many other people lack reliable internet access. Lack of internet access is a problem both in rural and urban areas, and it is a problem in both developed and developing countries. For example, 23% of households in Wayne County Michigan, which includes Detroit, lacked internet access in 2017. Solutions to this problem need to be inexpensive because many of the people without computer access have limited resources. Additionally, solutions need to work without requiring infrastructure such as laying copper wire or fiber optic cables. In these instructions we show how to build your own wifi access point so you can extend internet yourself.

About this Tutorial

These instructions are modular. You can follow parts of these instructions without necessarily completing the parts before or after it. For example, if you are interested in using a Rπ0 as an access point but aren't too interested in antennas, feel free to use any wifi adapter and ignore the steps involving making the antenna. If you are interested in making a custom Yagi antenna, skip straight to that part of the tutorial. The PCB layout files for the antenna are included.

The step to install the wifi adapter and the step to set up the Rπ0 as an access point were tested using Raspbian Stretch 4.14.52 and 4.14.79. Hopefully they will continue to work with future versions. However, these steps may need to be modified if config files for wifi access change in newer versions of the operating system.

Step 1: Gather Supplies

Picture of Gather Supplies

Supplies needed for the Raspberry Pi Zero Setup

Additional Supplies Needed for Setting up the Wifi Access Point

Additional Supplies Needed for the Custom PCB Antenna

PaulO207 months ago
How do you change the primary WIFI site? i.e. how do you enter the password on the new site?
warhawk80808 months ago
Nice...take the .gbr files, zip em up...upload em to JLCPCB.com, 10 for $5
Very cool design!
dhaykus04188 months ago
Do you have the direct OSHPark link to the antenna?

Thanks.
kuutei8 months ago
What is the gain on the PCB antenna like? What kind of range difference does it make vs the default antenna?

Amazing guide, I love the simple thoroughness of it.
Nice design. This would be great for setting up wifi connected miniature electronics.