Before starting, it is important to point out that the below is a re-write of the existing information available from the Bitaxe GitHub page, and elsewhere online.  The purpose for the re-write is to make this as easy as possible for anyone to read through and build a Bitaxe themselves.  It is somewhat advanced - but I think anyone could do it really.

It is also important to note that the Bitaxe project is a live and evolving project (there are updates to software, new boards/revisions to hardware) from time to time - a Bitaxe Supra has emerged now that has 4 ASIC chips from the Antminer S21 - hard to keep up!

I will link to the GitHub page throughout the guide - and try to maintain the links as things may change.  But please refer to the GitHub as your Master resource - this guide is a n00b / as-layman-as-possible guide.

Building a Bitaxe Ultra from scratch

If you're keen to build a Bitaxe from the ground up - this guide will walk you through the steps to do so - thats everything from ordering your own PCBs, components, soldering, installing firmware, updating, and getting the little guy hashing.  This is the long version of the guide (bit more text-heavy/walkthrough) - there is a short version with quick steps and links if you prefer to dive right in.

Table of Contents:

1. Ordering the Printed Circuit Boards (PBCs) Yourself
2. Ordering components
- PCB parts
- ASIC
- Heat Sink & Fan options
- OLED display 
- Power Supply 
3. Soldering / building your Bitaxe
4. Installing ESP-Miner Firmware on the ESP32
5. Set up and connecting to a Pool

>1. Ordering the Bitaxe PCB

PCBs can be ordered from a number of providers.  Perhaps even in your local country/area.  This guide refers to some of the major providers, which are all fairly similar.  My personal experience is with JLCPCB as they're based out of Hong Kong (closer to me than PCBWay and SeeedStudio - who are just a tiny bit further north in Shenzhen, China). But any of these will suffice!

To order PCBs with any of the above we need PCB schematics and design files to give to the PCB manufacturer to print.  These files can be found in the Manufacturing Files folder of the Bitaxe GitHub.  These files are .GBR files, or Gerber files.  Gerber files store all of the shape and location data for each part and layer of the PCB.

There are multiple files for a single Bitaxe PCB.  Go to your chosen PCB fabricators website, find the place to start an order or get an instant quote and you will see the place to upload to gerber files (screenshot example below).

Some of these sites will give a multitude of options for the PCB fabrication - but here are the requirements for the Bitaxe (scroll through the options and keep an eye out for these ones to make sure they're what you're ordering):

*PCB - 4-layer
*6mil trace/space
*0.3mm hole compatible
*1oz outer layer thickness / 0.5oz inner layer thickness
*Stencils - YES

(screenshot: Example of the PCB ordering page /config options from JLCPCB.com)

Most of the attributes can be left as default as some things, such as PCB dimensions, are in the gerbers themselves.

There should be an option to order stencils as well.  The stencil files are provided in the GitHub Folder with the rest of the gerber files as "paste".  Stencils are metal sheets with cut outs for solder paste to be applied.  It makes it much easier to place and weld the components to the PCB and keep everything neat and tidy.

(image: PCB ordered from JLCPCB with Stencil behind the bubble wrap)

- Ordering the ASIC

Quick one here really.  AliExpress has a few sellers with BM1366 chips.  There are two types: BM1366AL and BM1366AG - both work according to the GitHub.  Here's a link taken from the Bitaxe GitHub for an AliExpress listing for the chip: NBTC on AliExpress BM1366.

- Ordering Components

Skot has made this extremely easy by providing a BOM (build of materials) in the Manufacturing Files Folder - this is a spreadsheet with each component, its placement on the PCB, the quantity required, the manufacturer part number, and even the DigiKey part number.  Again, there are a few providers online for electronics components that may be able to fulfil the whole BOM, but I found DigiKey the easiest to navigate, order, and track - and they had all components.  Other sites I tried were missing or out of stock of 5-10 of the components - I was hoping to source them locally in Australia.

You could even use the BOM to source each part yourself from various suppliers - but why do that when its been made so easy for us already.  DigiKey are global and ship just about everywhere.

Head on over to the DigiKey website, register an account, and then go to 'Lists'.  On the Lists page you can upload the Build of Materials spreadsheet you downloaded from the GitHib Manufacturing Files folder.  After its uploaded you'll be taken to a screen to map the spreadsheet columns:

(screenshot: DigiKey List Mapping page)