Vaibhav Saini


Building Your Own Ethereum Hardware Wallet For $5

In this post we will build Firefly hardware wallet.

It’s an open-source, affordable, air-gapped hardware wallet for Ethereum you can build at home for around $5 in parts.

Here is a short video of its final working model.

Here are some of its features:

  • Low Cost: Build it yourself for about $5 with an Arduino, a 2.4GHz radio, an OLED display and a few odds and ends.
  • Air Gapped: Not connected by wires and cannot send wireless signals, keeping your private key safe from hackers.
  • Mobile Friendly: Works with any smart phone to prepare and send transactions or sign secure messages.

Let’s make one for yourself

There are a lot of options and flexibility when building a Firefly. You may design your own case or use one of our 3D printable cases. To get started, it is recommend using this breadboard version.


You can also customize the source code and add your own interesting features.

To get started, you will need a handful of parts, which are available from many sources, varying in price, delivery time and quality.

Some links are provided below to get the components to build Firefly(I am not affiliated with any of the vendors). In general, Amazon will arrive much quicker, but with a much higher price tag. Items from eBay will often be much cheaper, but ship from China, so may take longer to arrive. For purchasing in large quantities, Alibaba is by far your best choice, but also the most complicated.

Parts List

Here you can find code for the IOS app.

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