SR6PCB

A servo controlling hydra designed for the SR6. This motherboard delivers 100W USB-PD from a compatible power source, a combined data/power bus, and up to 13 servo connectors. Voltage delivered to all servos is configurable, with settings for 6V, 7.4V, and 8.4Vs for high torque and high speed servo models.

Designed to run 6 main axis servos, twist + valve servos, a brushed motor driven pump, with additional channels for user addons and future device support.
Note: image shows prototype, production hardware will ship from factory with servo headers pre-populated.

USB-PD

This device sinks up to 100W (20V @ 5A) and regulates down to servo voltage with a high current switch mode power supply. With over 90% efficiency, this results in a current spike capacity of over 15A with a generic 100W USB-PD power source.

WiFi out of the box

The device ships with modified ESP32 firmware, supporting configuration using a captive portal for user customization. The connection is facilitated by a ESP32S3, supporting BLE and 2.4GHz WIFI 4.

Serial Connection Support

The PCB has a single USB-C connector that can simultaneously be used for USB-PD and device command connection to the native ESP32S3 serial peripheral. In this arrangement the upstream host must provide 100W PD and data connection. For USB-C hosts that do not support device PD pass through, as USB-PD Wye can be used to inject USB-PD while passing data to a non-PD upstream host.
Off the shelf consumer USB-PD splitters (data, not audio only) may work, but we make no guarantees about compatibility with 3rd party parts. The Millibyte USB-PC Wye has be tested and confirmed to function well with the SR6PCB.

Brushed Motor Controller

The SR6PCB has an integrated H-bridge driver, suitable for full control of a brushed motor, or partial control of up to two half H-bridge driven devices. These outputs can be driven as continuous outputs using PWM (configured in the http interfaces). Internally the driver triggers are connected to GPIO8 and GPIO18.

User Expansion

Two unassigned GPIO pins are broken out for user use with buttons or output peripherals with collocated GND connections for convenience. Additionally a 5V I2C header breaks out the I2C bus for use with displays or other sensors. A UART connection is included on board for debug purposes, or device control when using a dedicated PD connection. 

The servo motor connections are labeled and may be used as GPIOs or generic PWM outputs. The only internally reserved lines are the brushed motor driver outputs and power supply enable control.

Sensors and Feedback

The SR6PCB can use the internal ADC to monitor all four power buses on device. The 3V3, 5V, Servo Voltage, and Input Voltage busses are are shifted down to ADC input levels and available to read in software, fully supported in the Millibyte firmware branch.

Disclaimers and Warnings

Servomotors and other electronics may result in injury or fire when improperly used or used outside their design parameters. The user assumes all risk resulting from the use of this device. 

This product is an experimental development board that may source dangerous amounts of power. Connect to only certified, 100W rated USB-C power delivery cables and equipment. Users assume all risk associated with operating product.

Documentation: https://github.com/millibyte-products/SR6PDPCB

International Shipping

At the moment, DHL is the recommended shipping option for non-US addresses. Packages will be shipped duty-paid where available. USPS is available for some international shipping, but please be aware any duties and fees may be levied at time of delivery.

Customs information

The SSR6PCB is classified as a development board, HS Code 8473.30.11 It is intended for use in general research and development, hobbyist, and DIY applications. These include (but are not limited to) 3D Printing, Robotics, and/or electromechanics.

Current Shipping Hardware Revision: HW1.0