Versions

Note

This content is highly time-sensitive. Please check the Last Updated Time at the bottom of the page. If it hasn't been updated for a long time, you may ask in the group or remind @wanzi to update it.

TIP

The term official version mentioned below refers to the version developed by the BMCU development team.

Overall Versions

There are generally two main versions: the 130 motor version and the 370 motor version.

Chronological Order

• 130 Motor Version (outdated, no longer maintained): The earliest version with a complex clutch structure. Once properly adjusted, it does not require any additional support during printing and produces no noise.
• 370 Motor Version (Early) (outdated, no longer maintained): Changed to direct-drive motor with active feeding. Easier to assemble but prone to 5-way explosion ("wu tong bao").
• BMCU-B (370 Ball Bearing Version) (outdated, no longer maintained): Based on the early 370 version. Replaced the optical filament detection hole with a ball bearing blocker, solving the issue of difficult calibration and blockage caused by debris.
• BMCU-C (370 Hall Sensor Version) (latest, strongly recommended): Upgraded from the previous version, replacing the optical buffer with a Hall sensor buffer, completely eliminating the 5-way explosion issue and significantly reducing noise.

The early 370 version and the ball-bearing 370 version share compatible firmware. It is recommended to use firmware version 3-14, which is less prone to 5-way explosion.

Additional variants:

• 180 Motor Version by group member @bai_xiao_tao: Based on the 130 version, only the motor size was changed.
• BMCU370x SMD Microswitch Version, modified further by group member @xingchen: Based on the early 370 version, achieving similar results as the ball-bearing version. This version uses a microswitch instead of optical filament detection, avoiding issues where debris could block the optical hole. However, a corresponding modified motherboard is required.
• Modification authors are welcome to contact @wanzi to have their versions added to this wiki.

The 130 version and 370 versions (early and ball-bearing) share compatible motherboards, but differ in firmware, housing, and some mechanical components. Be sure to choose one version and understand the differences.

Tip

The 370 version uses active feeding — continuously feeds until the buffer is lifted; feeding stops when the buffer light turns off.
The 130 version uses passive feeding — the spring-loaded buffer compresses as filament depletes; feeding starts as soon as the buffer light turns on.

130 Motor Version

This version requires firmware v0.2

This is an early version. Its key maintenance point lies in the triangle plate clutch mechanism. It works particularly well with A1 series printers, offering good stability, though its structure is relatively complex. Issues such as unreliable triangle plates still exist.

Tip

The Mabuchi FF130-SH motor used in this design appears to only be available via Xianyu. For more information, refer to the Bill of Materials.

The related materials for this version can be found in the group file /bmcu integration package. This site includes an installation guide for this version, and a video tutorial is also available on Bilibili.

180 Motor Version

Created by group member @bai_xiao_tao, this is a special variant of the 130 motor version, designed to address the difficulty in sourcing the 130 motor. It shares the same firmware and structural design as the 130 version.

130 Ball Bearing Version

Made by a group member. Currently has limited documentation available.

370 Motor Version

It is recommended to use firmware version 3-14

WARNING

Current issue: BMCU-B (370 Ball Bearing Version) and earlier versions suffer from 5-way explosion due to the direct-drive feeding mechanism. Firmware version 3-14 reduces this problem. You can also mitigate it by disabling retraction during cutter operation, using an extended buffer, external buffer, or adding a stabilizing print piece around the 5-way connector.

This version has a simple structure, and the motors are easy to source. This motor became the basis for BMCU's P1 series printers, since the 130 motor was too slow and stable, causing feeding failures.

This version is also suitable for A1 series, and P/X series printers (@xingchen: seems more suitable for P1 series).

Related materials for this version can be found in the group file /370 motor documents.

Housing Versions

Note

There are many different housing versions with varying quality. It is recommended to follow the tutorial and use the version demonstrated in it.

PCB Versions

Original Version (Official)

This is the standard official version, nothing special to note.

Open Source Link

Type-C Version (Official)

This version adds an onboard USB-to-TTL CH340 chip, eliminating the need for an external adapter during firmware flashing. Otherwise, it is identical to the standard version.

Open Source Link

BMCU370x Modified by Xingchen

This is the motherboard used for the Xingchen microswitch modification.

It features an onboard USB-to-TTL CH340 chip, allowing firmware flashing without an external adapter. It also includes diode protection for the microcontroller.

The filament detection section has been upgraded to optionally use a microswitch instead of optical detection.

An additional DCDC buck converter is included, and the motor voltage can be switched between 12V and 24V via solder pads.

This version maintains compatibility with the original version.

For more details, see the open source link.

Open Source Link

Hall Buffer Version (Official)

This is the latest motherboard currently under testing by the development team. Compared to the previous generation, it mainly adds:

• 485 floating ground protection (using PMOS)
• Hall buffer (upgraded from digital buffer to analog buffer)