OSSM-RS

An alternative firmware for OSSM written in Rust

You can find the original hardware and software here

Features

• Full RS485 based motor control
• Motor settings set automatically
• S-curve motion planning
• Strict mechanical bounds checks
• Adjusting depth, velocity, and stroke start on the fly
• Off-the-shelf control board support
• Patterns

Trying It Out

Getting Ready

1. Install Rust using the instructions here

• Windows
  • Download and run rustup-init
  • Select "Quick install via the Visual Studio Community installer"
  • Select "Proceed with standard installation (default - just press enter)"
• Linux or MacOS

  curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

2. Open a terminal

3. Install the ESP Rust toolchain for Xtensa devices as well as the espflash tool for flashing devices by running the following commands:

cargo install espup --locked
espup install
cargo install espflash --locked

More information can be found here

Compiling And Uploading

1. See the supported boards section to see if your board is supported and use the feature flag in the next step

2. If on Linux or MacOS set the environment variables with:

. $HOME/export-esp.sh

3. Compile with and upload with:

cargo xtask run <board_name>

First Boot

When you first start the machine it may appear that nothing is working.

Power cycle everything! Disconnect the motor power supply as well as the controller board for a few seconds and then reconnect everything.

This is necessary because the motor comes with a baudrate of 19200 from the factory. This is very slow and on first boot OSSM-RS will change it to 115200 which requires the motor to be power cycled to take effect.

If you check the logs you should see: Motor baudrate updated. Please power cycle the machine!

Board Support

See supported boards

Remote Support

• M5 remote
• OSSM BLE Protocol

Motor Support

57AIMxx RS485

Connect a ~1500uF >50V capacitor between the power pins. 2200uF 63v was found to work well

Power pinout (motor shaft facing up):

Data pinout used for the diagrams (motor shaft facing down):

Pin #	Function	Description
1	NC
2	RS485_A	RS485 +
3	RS485_B	RS485 -
4	NC
5	NC
6	COM	Ground for RS485 and outputs
7	WR	Alarm output (active low)
8	RDY/PF	Encoder pulses
9	ZO	Encoder zero
10	RS485_Power	5V in the datasheet, but seems to take 3.3V just fine

Patterns

Built-In Patterns

OSSM Patterns

These are designed to closely mimic the patterns provided by the stock OSSM firmware

• Simple
• TeasingPounding
• HalfHalf
• Deeper
• StopNGo

OSSM-RS Patterns

These are designed to take advantage of the features provided by OSSM-RS

• Torque

Making Custom Patterns

The list of patterns is stored under pattern/mod.rs

The easiest way to create your own is to copy, rename and modify one of the existing patterns in the pattern directory. Don't forget to add it to pattern/mod.rs as well.

For details see the documentation of the Pattern trait and the related structs (PatternInput and PatternMove)

Roadmap

Open an issue if you want to see something added

• Off-the-shelf control board support
• Patterns
• R&D wireless remote support