JuicyBoard: Modular Robotics Platform

Description

Project url http://plugg.ee.

It is now live on https://www.crowdsupply.com/plugg-ee-labs/juicyboard.

I created this platform to make it easier to build 3D printers and CNC machines with special configurations without having to redesign control boards. I make unusual 3D printers (like multiple print heads/materials), a large size. My main frustration with existing boards is that they are static. You can to do a lot of manual hacking to customize, then the setup becomes unreliable and hard to debug.

The main idea is to have a board with only the core functions, then populate it with modules that you only need for the application. For example: to control a triple head 3D printer, you will need to populate:

• 6 stepper motor drivers (3 for XYZ, 3 for extruders)

• 1 module to control 4 heaters

• 1 for fan control, 1 for analog thermistor inputs

• 1 for digital end-stop sensing.

You can reconfigure that for another completely different project. The project is completely open source under GPL v3.0

Introduction

JuicyBoard is the base of a modular platform that makes it easy to build a custom 3D printer, CNC, router, or any other application that is driven by stepper motors. The idea is simple, unlike most of the control boards we’ve seen. JuicyBoard is not pre-populated with any drivers, switches, or other functional features, instead it only includes the components for common core functions (i.e. Microcontroller, USB port, SD card … etc). You can populate necessary feature modules for your application. The modularity of the platform gives quite the advantages over static board designs.

JuicyBoard Features

There are 2 models of JuicyBoard R1000A and R1000AX:

• [R1000AX Only] Triple Channel precision power monitors: measure voltage/current of all power domains

• ATX compatible input power connector (9V ~ 24V / 27A)

• USB Type-B data port: main port of communication

• USB Type-A connector for 5V output: power an external system like a Raspberry Pi

• 5V Switching Regulator (3A output): powers 5V logic and external system

• 3.3V Switching Regulator (1.5A output): powers 3.3V logic

• [R1000AX Only] LM5060 Hot Swap Controller: protects system from overshoots, undershoots and overloading

• LPC1769 ARM Cortex M3 MCU @ 120MHz

• [R1000AX Only] 100A PSMN1R2-30YLC,115 NFET Switch: used for shuting down the system in case of faults and emergencies

• Feature Slots: 15 for R1000AX and 10 for R1000A

• [R1000A Only] Micro SD Card Socket

• [R1000AX Only] Full Size SD Card Socket

Available Modules

R1001: Smart Stepper Motor Driver

This is a NEMA stepper motor driver based on TI’s DRV8825 chip. It’s a high-performance stepper driver capable of micro-stepping at 1/32 resolution. Current can be digitally set for every driver in 10mA increments. R1001 includes a temperature/voltage/current and monitors for real-time performance measurement and detecting problems. This driver includes its own embedded microcontroller that performs extended functions that can't be handled by the host.

R1002: Quad 1A DC Low Side NFET Control Switches

This module can control 4 small functions (i.e fans, LED’s) that consume less than 1A and runs at the high input voltage.

R1007: Quad 20A DC Low Side NFET Control Switches

This module can drive 4 heaters with strong 100A PSMN1R2-30YLC,115 NFETs from NXP, allowing steady and cool driving of 300+ Watts head beds. R1007 must be powered through its own auxiliary supply input and it is optically isolated from JuicyBoard (meaning, it can have its own separate power and ground, can be powered by up to 24V).

R1008: Dual Channel Platinum RTD PT100 Temperature Sensors

This module interfaces for two PT100 platinum resistor temperature detectors (RTDs) for precision temperature sensing (can have less than 0.2C error). It can work in 2-wire, 3-wire or 4-wire configurations.

Other Modules In the Pipe

I'm very open to designing new modules with new functions. Here are my thoughts at the moment.

• Optically isolated Quad Channel AC PWM power control with zero-crossing capability, can be used to control AC heat elements, which is much more efficient for large and strong heaters.

• Optically isolated AC spindle control.

• Particle.io Photon/P1 housing module, allows attaching Juicyboard wirelessly to the internet.

If you want something else please give me a buzz.

Use Cases

I've used JuicyBoard to build a couple of 3D printers and a CNC machine. Here’s a case where the system was used to control a triple extruder, triple head 3D printer (uses polystroooder) that can print 3 different materials. Here is how we configured a 10-slot prototype JuicyBoard to drive the printer:

• R1003: Wired as Analog inputs to read the temperature through thermistors, 3 hotends and one heated bed.

• R1001: 6x stepper motor drivers, 3 are actuating the motions axes and the other 3 are actuating the extruders.

• R1005: This connects to an R1007 module that is independently powered to switch, the hotend, and hotbed heaters.

• R1002: We used one channel to switch the layer fan.

• R1003: Wired as digital inputs, 3 channels were used to read inputs from 3 end-stop switches, the 4th was used to read from a z-probe (helps a lot with bed leveling).

• R1008 is still new, we’re planning to upgrade the machine with PT100 sensors instead of thermistors. It will take some extra machining as well.

Here's a video of my other 3D printing doing bed leveling through an IMU Z-probe: