Introduction to the EXPANSION HUB
REV ROBOTICS - EXPANSION HUB revrobotics.com
ANOTHER CONTROLLER CHOICE MODERN ROBOTICS REV ROBOTICS The Expansion hub does not replace the Modern Robotics System. It is just another option for teams to use.
REV ROBOTICS MAKES TWO HUBS ONLY ONE IS FTC LEGAL Control Hub Expansion Hub FIRST GLOBAL CHALLENGE FIRST TECH CHALLENGE
EXPANSION HUB PORTS
ANALOG AND DIGITAL PORTS NEED A SPLITTER TO USE THEM ALL 2 Analog become 4 4 Digital become 8 Do NOT use the splitter on the I2C ports 2/$3
INTEGRATED SENSORS • Battery voltage monitoring • Integrated Bosch BNO055 9-Axis absolute orientation IMU sensor • Current Monitoring [Not Available in Ver 3.1] o Battery o I2C Bus o Servo Bus o Digital Bus • Individual Motor Channel Current Monitoring and Control [Not Available in Ver 3.1]
NEED MORE PORTS? Two Expansion Hubs are allowed
SIZE COMPARISON MODERN ROBOTICS REV ROBOTICS
COST COMPARISON – 4 MOTORS, 6 SERVOS Modern Robotics REV Robotics $90 Power Distribution Module $150 REV Robotics Expansion Hub $160 Motor Controller Module $12 Level Shifters for motor encoders $30 Additional cables, etc. $70 Servo Controller Module $68 Device Interface Module $33 Integrated Gyro $33 Compass/Accelerometer $192 Total (with Team Discount) $454 Total
COST COMPARISON – 8 MOTORS, 12 SERVOS Modern Robotics REV Robotics $90 Power Distribution Module (1) $300 REV Robotics Expansion Hub (2) $320 Motor Controller Modules (4) $24 Level Shifters for motor encoders $140 Servo Controller Modules (2) $60 Additional cables, etc. $68 Device Interface Module (1) $33 Integrated Gyro (1) $33 Compass/Accelerometer (1) $684 Total $384 Total (with Team Discount)
TEAM DISCOUNT If you order your HUB through the FTC Team Registration page, you save $25 plus you get… • Free Cable Conversion Kit – normally $25 • Free Color/Distance Sensor – normally $14 • Free Touch Sensor – normally $6 • Free Switch Kit – normally $6
TEAM DISCOUNT Order direct from REV Robotics and at checkout enter REVHUB4FTC2017 This saves you $25 on addition Hubs (NO Free Sensors and FTC Cable Conversion Kit)
HYBRID SYSTEMS ARE LEGAL • Both the REV Robotics Expansion Hub and the Modern Robotics Core Modules can be used together. • BUT, if both systems are used together, the Expansion Hub must be powered by a power port on the Modern Robotics Power Distribution Module.
CABLES AND EXTENSION BOARDS JST PH 4-pin • Cable – 20cm 4/$3 • Cable – 30cm 4/$4 • Cable – 50cm 4/$5 • Extension Board 4/$4 All cables have the same female connector on each end. You will need the Extension Board to connect cables together.
LEVEL SHIFTER The Level Shifter allows 5-volt sensors to work with the Expansion Hub’s 3.3 -volt system. The following sensors require a level shifter • 5 volt Motor Encoders (Neverest & Tetrix) $3 • 5 volt Sensors (all I2C Modern Robotics)
LEVEL SHIFTER CABLING Encoder Wire Wires from Expansion Sensor Wire Hub Suggestion Since the circuit board has the connection information on the opposite side from the pin outs, I suggest using a red marker to mark the +5V side so its easy to connect cables to the Red mark +5V pin Cable Shifter correctly.
MOTOR & ENCODER CONNECTIONS
MOTOR & ENCODER CONNECTION USING LEVEL SHIFTER
SOME SENSORS REQUIRE A SENSOR CABLE (CROSSOVER CABLE) Modern Robotics I2C Sensor/Device This Sensor Cable is required to make many some sensors (Modern Robotics I2C) compatible with the Expansion Hub
SENSOR CABLE Reverses the ground and channel B wires $1
SENSOR COMPATIBILITY GUIDE Refer the REV Robotics Expansion Hub User Guide for a complete list
EXPANSION HUB GUIDE If you are going to use the Expansion Hub, I highly recommend you read this guide www.revrobotics.com/content/docs/REV-31-1153-GS.pdf
SERVO PORTS The Good News… The REV Robotics servo ports output a Pulse Width Modulation (PWM) of 500- 2500ms. This means your analog servos once again have a default range of 180 degrees, unlike MR’s 135 degrees.
SERVO PORTS The Good News… The REV Robotics servo ports output a Pulse Width Modulation (PWM) of 500- 2500ms. This means your analog servos once again have a default range of 180 degrees, unlike MR’s 135 degrees. The Bad News… These servo ports only output 5 volts instead of 6 volts which is OK in most situations, but that equals about 17% less torque. There is also a 2 amp maximum for each pair of ports possibly limiting the use of several quarter scale servos simultaneously.
SERVO PORTS The Good News… The REV Robotics servo ports output a Pulse Width Modulation (PWM) of 500- 2500ms. This means your analog servos once again have a default range of 180 degrees, unlike MR’s 135 degrees. The Bad News… These servo ports only output 5 volts instead of 6 volts which is OK in most situations, but that equals about 17% less torque. There is also a 2 amp maximum for each pair of ports possibly limiting the use of several quarter scale servos simultaneously. More Good News… REV Robotics has solution to all of the Bad News…
SERVO POWER MODULE • Restores 6 volt output to all ports • 15 amps are shared by all ports • You should be able to run 6 analog quarter scale servos simultaneously • Status lights
SERVO POWER MODULE Status Lights • Green – Forward • Red – Reverse • Yellow – Neutral • Yellow Blinking – Not Connected • Blue - Power 12V
CONFIGURATION FILE
CONFIGURATION FILE - MOTORS
CONFIGURATION FILE - INTERNAL IMU The Internal IMU is automatically assigned to I2C Port 0, but you can assign Port 0 to any other I2C sensor.
MY CONCLUSIONS CONS PROS • Saves a lot of space. • Not proven in FTC competitions. • Much less expensive. • Level shifters and crossover cables can make wiring a little • Only one USB cable. more complicated. • I2C individual bus for each • No direct support for Hitechnic sensor. Therefore no need to and Lego legacy sensors. change sensor addresses. Would I buy the REV Expansion? Yes!
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