STEP400 is a 4-axis stepper motor driver designed for creative applications. An Arduino Zero, Ethernet shield, sensor inputs for homing and limiting, and four stepper motor drivers are combined elegantly on one PCB board. Then we provide a simple and creative coding environment to generate motion.

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STEP400 works especially well with Open Sound Control (OSC) via Ethernet. OSC is a common protocol for creative coding environments, so if you are familiar with environments like openFrameworks, Processing, Max, Unity, or Touch Designer you can easily generate smooth and precise motions with simple the Open Sound Control (OSC) protocol through an Ethernet cable.

STEP400 is also compatible with the official Arduino IDE Ethernet library so you can write your own code, too.

Functionality

STEP400 can drive 4 motors, from tiny to high powered ones. It uses STMicroelectronics PowerSTEP01 as driver chips. A single OSC command can generate positioning motion or constant speed rotation. Two drive modes are available: a smooth and accurate voltage mode, and powerful current mode, which can be used to drive high speeds.

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An open loop servo mode is available to track the target position stream in real time, like an RC servo. A simple configuration tool generates a readable JSON file, which can be loaded via a microSD card. Ethernet connectivity allows for the system to be easily scaled up.

Features & Specifications

• MCU: Microchip ATSAMD21G18A
• Ethernet controller: Wiznet W5500
• Stepper driver: STMicroelectronics PowerSTEP01
• DC-DC converter: ROHM BD9G341AEFJ
• Axes: 4
• Applicable motor: Bi-polar stepper motor
• Input voltage: 12-72 V
• Maximum phase current: 5 A (under ideal conditions)
• Power input terminal: M3 screw terminal
• Stepper output terminal: 3.81 mm euro style terminal block
• Sensor input terminal: 8 JST XA (B03B-XASK-1)

Open Sound Control (OSC) Protocol

The standard way of controlling stepper motors is with industrial Ethernet, which lacks compatibility with general network devices as well as open specification. This makes it more time-consuming than necessary to use it for any purpose other than factory automation.

Since STEP400 is a stepper motor driver designed specifically for creative applications, it uses the simple and easy-to-use OSC protocol to solve this issue. Open Sound Control (OSC) is an open-ended, dynamic, UDP-based protocol with a URL-style symbolic naming scheme . It is widely used in the field of electronic music and new media art.

Control of STEP400 involves Arduino Zero and Ethernet shield elements. You are free to decide how to control it. For instance, you could rewrite the Arduino sketch to be controlled by Artnet or WebSocket, or by basic USB serial data.

STEP400 Board Layout

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Each STEP400 board will come with four motor connectors.

Add-On Options

Electromagnetic Brake Board Add-On

An optional control board for stepper motors with an electromagnetic brake is available. It is easy to connect to the main board. An electromagnetic brake is only unlocked when the power is energized, so it can safely hold the load when the system shuts down or the power supply is unexpectedly cut off. To use this board, a motor with an electromagnetic brake is required and is not included.

Sensor Cable Add-On

The homing and limiting sensor connectors are JST XA. This style of connection is handy, readily available, and easy to attach, detach, and extend.

It is, however, necessary to crimp the terminals to the cable if you are making this connector at home. Crimping the terminals requires a bit of experience and some tools, which can be a hurdle for smaller projects. Because of this we are providing a cable with a connector crimped on one end as an add-on option. The other end of the cable is cut off and can be used to solder any sensor or switch.

Comparisons

Born From The Needs Of Real Projects

STEP400 comes out of a number of projects we have done with stepper motors. We initially built the system using a combination of DIY modules, but as the system scaled up, the wiring became chaotic, causing all sorts of problems due to the unstable connections between modules and the length of the digital signal path.

After some struggles while working on projects, we realized that we should design a dedicated driver board that would put together everything we needed. Prototypes of STEP400 were created for our own purpose and have been used, tested and validated in a wide variety of real-world projects.

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Photos courtesy of TASKO Inc, anno lab, invisi., and dot by dot inc.

STEP400 In Action

Here are some examples of projects created with prototype versions of this board:

dot by dot | Flower Mirror

invisi. | Medium

WOW | Emerge

Development History

We originally developed a board to control eight small stepper motors. STEP400 was based on this design with a goal to control fewer, yet larger, motors. With this project, we aim to deliver a production version based on our current prototype. The original board that controls the eight motors will continue to be developed as a separate model called STEP800.

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Open Source Support & Documentation

• Documentation Wiki
• Board schematics
• Hardware project files
• Firmware

This repository is temporary and will be cleaned up and migrated to a new location during the campaign.

Manufacturing Plan

We have manufactured 50 copies of the prototype in its 4th revision and are now field-testing them ourselves and via beta testers. We might make some minor improvements to the current design after field tests, in which case one more test PCB will be fabricated before placing the final order. This process would take some time. We plan to use a one-stop service for PCB manufacture and assembly, and for this purpose we have been in contact with several companies in China. The production process will take 1 month. We expect to complete production by January 2021, followed by tests and packing in Tokyo, and we will be ready to ship the product to Crowd Supply by the end of February 2021. From there, Crowd Supply will handle order sorting and distribution. You can learn more in the Crowd Supply Guide.

Fulfillment & Logistics

STEP400 will come with 4 Euro style terminal blocks for stepper motor connectors, and 4 small heatsinks for the driver chip. They will be delivered to Crowd Supply’s warehouse for final distribution to backers worldwide. Please see the Crowd Supply Guide for information about VAT and Customs.

Risks & Challenges

There are no replacement parts for some components in STEP400. Depending on their availability, this could cause a delay in production. We will work with a PCB assembly manufacturer to prepare alternative suppliers to ensure that the manufacturing process is not delayed.

Furthermore, although we do have extensive experience in developing dedicated devices for a wide variety of projects, we do not have much knowledge of large-scale import, export, and sale. We will continue to work hard on the import/export documentation and certifications to ensure that there are no issues with logistics.