BTCIOT Tutorial: Bowser, DIY Bitcoin Hardware Wallet

## BTCIOT Tutorial: Bowser DIY Bitcoin Hardware Wallet - Summary

This podcast episode provides a comprehensive tutorial on building and using the "Bowser" project, a DIY Bitcoin hardware wallet disguised as a Tetris game using an M5 stack microcontroller. The hosts emphasize the value of self-reliance in Bitcoin security, encouraging users to understand the underlying technology by building their own hardware wallets. While suitable for securing smaller amounts of Bitcoin (up to a few thousand pounds), the hosts caution that it’s not a replacement for more robust solutions like Trezor or Ledger for larger holdings. The tutorial walks through the entire process, from initial setup and seed phrase generation to transaction signing using Electrum.

The Bowser wallet leverages Steppen’s Bitcoin Arduino library and the versatility of the M5 stack to create a functional and visually appealing device. It utilizes an SD card for transaction broadcasting and data storage, including the crucial seed phrase. The process involves importing a master public key into Electrum to create a watch-only wallet, generating unsigned transactions on a computer, transferring them to the Bowser for signing, and then broadcasting the signed transaction. The episode also delves into the code, highlighting key files and library installation procedures, and demonstrates the hard reset functionality, which generates a new seed phrase. Throughout the tutorial, the hosts stress the importance of secure seed phrase management, suggesting techniques like splitting and scrambling.

### Main Topics Discussed

• DIY Hardware Wallet Construction: Building a Bitcoin hardware wallet using the Bowser project and an M5 stack.
• Bowser Project Overview: Functionality, components (M5 stack, SD card), and design (Tetris decoy).
• Seed Phrase Generation & Storage: The process of generating a new seed phrase using the Arduino random function and securely storing it on the SD card.
• PIN Creation & Security: Creating a PIN and storing its SHA256 hash for authentication.
• Transaction Signing with Electrum: Importing a master public key, creating a watch-only wallet, generating unsigned transactions, signing with the Bowser, and broadcasting.
• SD Card Data Management: Understanding the purpose of key files like `key.txt` (seed phrase), `browser.txt` (hard reset), and `past.txt` (PIN hash).
• Library Installation & Code Overview: Setting up the Arduino IDE and installing necessary libraries, and a brief review of the project code.
• Security Considerations: Limitations of the Bowser wallet for securing large amounts of Bitcoin and the importance of secure seed phrase management.

### Key Quotes

• "We don't place much emphasis on people building their own hardware wallets." (Highlights the importance of understanding Bitcoin's inner workings)
• "It's got a private key stored on here." (Emphasizes the security aspect of the hardware wallet)
• "I would feel confident putting, you know, an okay amount of funds on one of these hardware wallets." (Acknowledges the Bowser's suitability for smaller amounts)
• "Splitting up your seed phrase is a good idea, and then having some sort of algorithm to jumble them up as well, before you split them is something you'll be able to remember." (Provides a practical tip for seed phrase security)

### People Mentioned

• Shamae: Podcast host's co-host.
• Steppen: Creator of the Bitcoin Arduino library.
• Light Graves: Mentioned in relation to Steppen's library.
• Podcast Host: (Unidentified) - Guides the tutorial.

### Bitcoin Prices Mentioned

• 100,000 sats
• 2000 sats
• 50,000 sats