Closed Source is Antithetical to Bitcoin

Presenting: The supraHex

supraHex is a follow on to the bitaxe that incorporates six BM1368 ASICs from the Antminer S21

Goals

• Standalone: can mine directly to your pool over WiFi. No External computer needed.
• Embedded: low cost, low maintenance, high availability, high reliability, low power.
• ASIC: based on the very efficient BM1368 from Bitmain.
• Versatile: solo/pool mining, autotune power/heat/efficiency.
• Open Source: All design files are provided.

Features

• ESP32-S3-WROOM-1 wifi microcontroller on board
• TI TPS546D24ARVFR buck regulator steps down the 12V input to power the chain of BM1368
• TMP1075 measures inlet and outlet PCB temperature.
• Microchip EMC2302 Controls dual fans
• Header for optional status LCD
• BAP (Bitaxe Accesory Port)
• ASIC Chip temperature directly from the ASIC's

BM1368

• The BM1368 is a undocumented SHA256 mining ASIC from Bitmain. It's mostly used in the Antminer S21
• Bitmain claims the BM1368 has 17.5 W/TH efficiency
• The BM1368 is available (new) for around $20~29 each.

Current Status

• v701 hardware is working! Hash rate is fluctuating between 4 TH/s and 4.2 TH/s.
• Power draw is around 75W @12V.
• ESP32 miner firmware will configure the power supply to run at the proper voltage.
• This is an advanced build! If you don't have experience building boards, you should probably go build a single ASIC bitaxe first to get the technique down.

Revision List

• V701 is the current working version of this board. If you want to build this, pull down this git tag.

Hardware

• BM1368 from NBTC. The PBVariant seems to work fine.
• Heatsink 90mm long variant. This will need to have threaded M3 mounting holes added. See the KiCad board file for the pattern
• Fans At least one 80x80mm 12V 4-pin fan. Like the Noctua NF-A8 PWM. Possibly two.
• Enclosure (several sellers) 130mm long variant. The supraHex needs to be run inside an enclosure to force air through the heatsink and effectively cool the BM1368s
• All of the parts on the board are listed in the KiCad BOM

Software

• ESP-Miner-Multichip is still being updated to support multiple ASICs

Power Supply Requirements

• supraHex takes 12V DC input via screw terminals. Power supply should be capable of 100W
  • This 120W Brick technically works, but gets a little warmer than it should. You'll need to change the end.
  • 12V 15A 110V AliExpress Bare PSU

Building

• Check out building.md for PCB ordering tips
• Check out assembly.md for assembly tips