The REV Control Hub is an affordable robotics controller providing a platform for the interfaces required for building robots. The Control Hub works with the Expansion Hub and Driver Hub to create a complete robotics control system for both the classroom and the competition. These devices are most commonly used within the FIRST Tech Challenge (FTC), FIRST Global Challenge (FGC), and in the classroom for educational purposes.

How to use this documentation?

This documentation is intended as the place to answer any questions related to the REV Robotics Control Hub, Driver Hub, and Expansion Hub used in the FIRST Tech Challenge and FIRST Global Challenge.

• Looking to get an idea of how to use the system before your Control Hub arrives? Reading through each section will help, but we specifically recommend the guides on getting started with the Control Hub and the programming language options section.

• Have a specific question? Feel free to head straight to it using the navigation bar to the left. Each section is grouped with other topics that are similar.

• Having trouble finding what you are looking for? Try the search bar in the upper right or read the section descriptions below to find the best fit.

Getting started building robots can be an intimidating process. The following documentation is here to make getting started a bit easier. There are a number of examples to get started with the Control System and we are committed to adding content to make it more accessible for people to use REV. If there is a question that is not answered by this space, send our support team an email; support@revrobotics.com. We are happy to help point you in the right direction.

What is in each section?

‌System Overview

‌This section contains information regarding all of the major mechanical specifications of the REV Control Hub and Expansion Hub. These sections include port pinout information, protection features, and the types of cables used with the devices.

Getting Started

Take the Control Hub or Expansion Hub from out of the box through generating the first configuration file. This includes the process for changing your Control Hub's Name and Password as well as connecting to your Driver Hub. Also includes information on ways to add additional motors to the control system through adding a SPARKmini Motor Controller or an Expansion Hub.

Updating and Managing

This section covers how the information needed to keep your Control Hub, Expansion Hub, and Driver Hub up to date with the latest software. This section also includes information on using the REV Hardware Client to update, program, and manage these devices as well.

Programming

From just getting started by writing your first OpMode to working with closed loop control, this section covers the information needed to start programming.

Sensors

Sensors are often vital for robots to gather information about the world around them. Use this section to find how to use REV sensors and information on the different sensor types.

One of the key aspects of troubleshooting is understanding the most common issues that occur in a system. Once those problems, and their indicators, are defined a flow has to be created. For example, a check engine light in a car indicates any number of issues. When a cars check engine light comes on, a mechanic pulls the codes from the car to narrow down the issue to a specific part of the engine. Even if the code leads to a specific part of the engine, like the transmission, it is not always indicative of the exact problem. However, there is a process flow. Each step narrows down the problem to a potential solution. Troubleshooting the REV Control system is no different!

Many issues can be solved by systematic troubleshooting without needing to contact REV Support. Take a look at the troubleshooting tips below for help in determining the cause of the issue you are seeing. Should you need to contact us, describing the steps you've taken in detail will help us get you up and running quickly. The section is divided into general best practices, Control Hub (REV-31-1595) troubleshooting and Expansion Hub (REV-31-1153) troubleshooting.

General Best Practices

Before diving into common troubleshooting paths its important to understand the general guidelines, or best practices, for Control System Health.

• Charge the Battery - While a charged battery and phone are crucial to a healthy control system in general; it is also helpful to ensure batteries and phones are charged before a match.

• Update - The applications, firmware, and operating system have periodic updates to improve the control system. Keeping the control system up to date ensures the best performance!

• Isolate the Issue - This is key to effective troubleshooting. Many issues can show the same symptom, so eliminating failure points one at a time is critical to finding the root cause.

Maintaining and taking care of the 12V Slim Battery is also important for troubleshooting purposes. All rechargeable batteries have a finite lifespan however following the best practices for the 12V Slim Battery can extend the lifespan of the battery.

ESD Mitigation Techniques

During Match Play or practice on a competition field, some FTC teams may encounter Electrostatic Discharge (ESD) between the foam tiles and the robots. Below are some methods to help mitigate the effects that any ESD may have on your robot.

1. Ensure that you plug USB devices, such as a Camera, into USB 3.0 Port on your Control Hub. Using the USB 2.0 Port may cause ESD to affect your Control Hub's Wi-Fi Chip

2. Add a Resistive Grounding Strap, the 470Ω resistor will help minimize high discharge events from robot electronics and the frame

3. Treat the practice area with an anti-static spray

4. Other ESD mitigation strategies can be found within the documentation provided by FIRST: Managing Electrostatic Discharge Effects

USB Port Care

Regular maintenance of your DUO Control System's USB ports will help prevent issues in the future. Here are a few tips to make sure your hardware stays in good shape.

• When plugging in USB cables, don't force the connector too roughly. This can push the USB port into the Control Hub or Driver Hub

• Be sure to keep all ports clean and free of debris. Before cleaning with compressed air, be sure to turn off your device

• When transporting or storing a Driver Hub, remove all USB cables from the ports

After receiving the Control Hub it is advised to unbox the device, power the Control Hub on, and start the configuration process. Below are the required materials to run through the initial bring up of the Control Hub and links to the different steps of the process.

Required Materials

• Control Hub (REV-31-1595)

• 12v Slim Battery (REV-31-1302)

• Driver Hub (REV-31-1596)

• Gamepad (REV-31-2983, REV-39-1865, or approved FTC gamepad)

• USB A to USB C (included with Control Hub)

• Windows PC running the REV Hardware Client

Optional Additional Materials needed to Connect an Expansion Hub:

• Expansion Hub (REV-31-1153)

• XT30 Extension Cable (REV-31-1392, included with Expansion Hub)

• JST PH 3-pin Communication Cable (REV-31-1417, included with Expansion Hub)

The RGB LED located on the Control Hub (REV-31-1595) and Expansion Hub (REV-31-1153) near the RS485 ports and on the bottom of the Driver Hub (REV-31-1956) provide user feedback regarding the status of the Hub. Below is a Table of the Blink Codes.

Control Hub

Robot Controller Application 6.0 or Higher

If a Control Hub is running Robot Controller Application 5.5 or lower the LED Blink Codes for the Hub will be the same as an Expansion Hub running Firmware Version 1.7.0 or higher.

Driver Hub

LED A

LED B

Battery Status LED

Expansion Hub

Firmware Version 1.7.0 or Higher

One of the first recommendations made to users of the REV Control System is to update Wi-Fi settings, specifically the name and the password.

All Control Hub's come with a default network name and password. It is useful to change the name and password especially in environments where there are multiple Control Hubs running like at an event or in a classroom. Changing from the default adds an element of network security to the Hub by reducing the potential for access from outside sources.

The Control Hub (REV-31-1595) can utilize either the 2.4 GHz or 5 GHz Wi-Fi band. REV Robotics advises that during competition teams utilize a 5 GHz channel for robot communication. Consult the table below for Driver Station devices that can operate on the 5 GHz band.

Supported Android Devices and Wi-Fi Band Capabilities

As of the 2024-2025 FTC season, Android phones must be running Android 7 (Nougat) or newer to be compatible with the Driver Station App. Please check the game manual for full rules.

The following section will highlight how to access and make changes within the Wi-Fi settings. This section will use the REV Hardware Client to showcase how to make these changes. Once a user has connected to the Robot Controller Console, either via the Hardware Client or a web browser, the steps for accessing Wi-Fi settings are the same.

Steps to Updating Wi-Fi Settings

While in the Robot Controller Console select the menu button. In the image below the menu button is highlighted by an orange square in the upper right-hand corner.

When the menu opens, select Manage.

The Manage page is where the Wi-Fi Settings live. The following steps will show and discuss each change as it is made. Please keep in mind the following warning while moving through the steps:

You will need to reconnect to the new Wi-Fi network after changing the name and/or password. This is true for any Wi-Fi connection, but if you are accessing the REV Hardware Client via a USB connection the Hub will stay connected. Though, you may need to close and reopen the Hardware Client in order to see the changes.

Changing Control Hub Name

Under Wi-Fi Settings, there is an option to change the name of the Control Hub.

For FTC teams you will want to change the name from the default to team number - RC. (i.e. 99999-RC)

Changing the Control Hub Password

Under Wi-Fi Settings, there is an option to change the password of the Control Hub. There are not any restrictions on the password. Changing it from the default is advised but it does not have to change to anything complicated.

Changing the Wi-Fi Band and Channel

The Control Hub is capable of utilizing either the 2.4 GHz or 5 GHz Wi-Fi band. This change is also made within the Wi-Fi Settings.

The Robot Controller Console makes it easy to change between the 2.4 GHz an 5GHz bands. It is advised to check the Legal Android and Wi-Fi Band Capabilities table to determine which band to operate in.

Once a Wi-Fi band is chosen there are two options for dealing with Wi-Fi channels. One option is to let the Control Hub auto default on a channel. The other is to set a specific channel. Both options can be accessed via the drop down menu under the Wi-Fi channel section of the Wi-Fi settings.

It is valuable to know how to change the Wi-Fi Band and Channel as technical staff at an event can request to change those settings.

Before configuring your Control Hub, devices must be connected to the Control Hub. Below is a sample wiring diagram to show a sample of actuators and sensors usable with the Control Hub.

Wiring Best Practices

Sometimes poorly wired FTC robots can quickly become a tangled mess. Good wire management is crucial for two reasons: it simplifies troubleshooting electrical issues and prevents them from arising in the first place. Here are some helpful tips to keep in mind when wiring your robot effectively.

• Use cables with appropriate lengths to avoid excess cluttering the robot. Alternatively, if a cable must be longer than needed, utilize the full length by routing it neatly.

• Proper cable management keeps everything organized and accessible. Zip ties and Velcro straps are popular choices for their ease of use and adjustability.

• Secure cables away from the areas where the robot might move, such as the drivetrain or arm mechanism.

• Label your wires according to their function. This is especially helpful since wires may be difficult to access later, and clear labels will save you time deciphering their purpose.

• Double-check your wiring with a smart tug before every practice and match to ensure all connections are secure.

For more information on the connectors and cables used with the Control Hub see the links below:

When you first receive your Control Hub (REV-31-1595), you will have to connect it to a supported Android Device, like a Driver Hub. The following section of the page will walk through how to pair a Driver Hub or Driver Station phone to a Control Hub.

Connecting the Driver Station with the Control Hub

Once you have powered on your Control Hub follow through the process for connection to either a Driver Hub or a Driver Station phone.

The Control Hub (REV-31-1595) and Expansion Hub (REV-31-1153) can each drive up to four DC brushed motors. As mechanisms are added to the robot the number of motor ports may not be sufficient. There are two ways to add more motors to the Control System, either the SPARKmini Motor Controller (REV-31-1230) or adding an Expansion Hub. The Following two rules give a general idea of when to choose one method over another:

• If one or two motors are needed, consider using the SPARKmini Motor Controller.

• If three to four additional motors are needed, consider adding an Expansion Hub.

For additional information on how to use a SPARKmini or how to add an Expansion Hub, visit the linked pages!

After receiving the Driver Hub it is advised to unbox the device, plug the Driver Hub in to charge over USB-C, and power on the Driver Hub. Below is the initial bring up process of the Driver Hub.

Required Materials

• Driver Hub (REV-31-1596)

• USB-A to USB-C Cable

• USB-A Wall Charger

Battery Installation

To install the battery place it with the REV Logo out and the -/+ located near the contacts for the device. Add on the rear door and screw in using the included M3 hardware.

Setting up the Driver Hub

When the Driver Hub is first powered up, or a factory reset is performed, an initial set up process is needed. Start by selecting next on the main screen to continue.

Select a local Wi-Fi network that has access to the internet, enter in the password for that network if required, and select next.

Time zone and date of the device are set by the local Wi-Fi network. Confirm these settings are correct before proceeding by the Next button.

Initial set up is complete! Select Finish to operate the Driver Hub.

Initial Update

After setting up the Driver Hub, the Software Manager application will open. Select the Update All button to start the download and installation of software updates for the Driver Hub.

Navigating the Driver Station Application

Once the Driver Hub is connected to a Control Hub, you will have access to the entire Driver Station Application interface. Like any application, understanding the major components that make up the Driver Station Application interface, will maximize your ability to utilize the application efficiently. Consider the following components:

Tips and Tricks

If you tap on area 4, it will switch to displaying the link speed and signal strength. It will go back to showing the signal strength and ping time if you tap it again.

The smaller number in area 8 is the lowest voltage that the Driver Station has observed from the Robot Controller. If you tap area 8, the lowest voltage will be reset to the current voltage.

Battery Best Practices

We suggest the following best practices to help optimize and preserve the health of your Driver Hub’s battery. It is not necessary to strictly follow these recommendations, however, consistently operating outside of these guidelines may lead to decreased performance.

• If you are not using your Driver Hub any time soon, it is best to turn it off to minimize the battery usage.

• Avoid temperature extremes, both high and low, when charging, using, or storing Driver Hub batteries. Elevated temperatures can accelerate degradation of the battery and can lead to significant safety risks. Although your Driver Hub is expected to get warm while charging, you should remove the Driver Hub from the charger if it becomes uncomfortably hot. It is also recommended to not charge the Driver Hub when the battery is 32°F/0°C or lower in order to best persevere battery health.

• If you need a faster charge, using a PD 3.0 fast charger would decrease the charge time but is not recommended for continuous charging. To get the best battery health, We recommend charging your Driver Hub before the battery reaches 20% charge. It is also best to remove your Driver Hub from the charger within 24 hours of reaching 100%, this would be even more impactful if you are using a PD 3.0 fast charger.

• Avoid use or storage of Driver Hubs in high-moisture environments, and avoid mechanical damage such as puncturing and impacts. Remove the battery from the Driver Hub for long term storage, such as over summer break. Store it in a dry temperature controlled environment around room temperature. To best preserve battery health, avoid storing the battery with low or no charge.

Connecting Gamepads

The Driver Station Application allows for the connection of two gamepads. When working with the Driver Hub these gamepads can be plugged into any of the three USB 2.0 ports. Once the gamepads are plugged in, you will need to initialize them. For the following example we will use PS4 controllers, such as the Etpark Wired Controller for PS4 (REV-39-1865).

To initialize the gamepad that will act as User 1 (gamepad1, in code) press the options button and the Xbutton on the gamepad at the same time. To initialize User 2 ( gamepad2, in code) press the options button and the O button at the same time.

If you want to use more than 4 motors or 6 servos, you can add an Expansion Hub to your robot. An Expansion Hub (REV-31-1153) can be added to a Control Hub (REV-31-1595) or another Expansion Hub. The Expansion Hub has all of the same ports as the Control Hub but without the wireless capability.

Control Hub vs Expansion Hub in FIRST

Adding an Expansion Hub to your Robot

Most Common Issues

Additional Troubleshooting

Driver Hub Shows as a "Control Hub in Recovery Mode"

Occasionally, the Driver Hub may show as a "Control Hub in Recovery Mode" after fully powering on and connected via USB to the REV Hardware Client.

To fix this issue you will need to perform a factory reset on the Hub.

"App Not Installed" Error

The following error in the Driver Station App can occur when the date/time is incorrect on the Driver Hub:

On the homepage the FTC Driver Station app can report an "app not installed" error after updating the OS and the app. This can also cause the Driver Hub to not allow you to open the FTC Driver Station app. To fix this do the following:

1. Remove the Driver Station app icon on the home page by clicking and dragging to the X icon

2. Drag the new icon from the app drawer on the home screen. The app drawer is accessed by swiping up on the home screen of the device.

Android Permissions Lock Out

If the FTC Driver Station app is locked out due to android permissions, a factory reset of the Driver Hub should resolve this issue. Please power on the device, then follow the steps below to perform a factory reset:

1. Tap the "Setting" icon

2. Tap the "System" icon

3. Tap "reset options"

4. Tap "erase all data" (factory reset)

Battery Installation

To install the battery, place it with the REV Logo facing out and the -/+ located near the contacts for the device. Add on the rear door and screw in using the included M3 hardware.

Digitizer Lines

Due to variances in the manufacturing process related to screen digitizer installation, some Driver Hubs have minor visible digitizer lines on the screens when the device is powered off. These lines are more prevalent in some units than others, but the presence or absence of digitizer lines does not impact the performance of the touch screen or unit in any way. Please contact us at support@revrobotics.com if you have any concerns about your specific unit.

Connecting to Control Hub

External factors, such as local Wi-Fi environment, play a part in the ability to establish or maintain a connection between a Control Hub and a Driver Station device. Like all aspects of of troubleshooting its important to isolate an issue by asking questions and discovering the answers! As you work on troubleshooting consider the following questions:

• Is your system operating on a 2.4 GHz band or 5GHz band?

  • REV recommends, if you have a dual band Driver Station device, that you operate on the 5GHz Wi-Fi band. Check out the Updating Wi-Fi Settings section to learn more about making this switch.

• What is your local Wi-Fi environment like?

  • Local Wi-Fi environment effects the consistency of a connection to the Control Hub. Use a Wi-Fi analyzer to check the local environment for channels that are cluttered with Wi-Fi networks. Change the Control Hubs Wi-Fi channel to a channel with the least amount of overlap with other networks.

• Are you in a school or a place of business?

  • In addition to the amount of local networks in an environment its important to understand what those local networks are capable of. For instance, some school districts have security measures in place that block unauthorized Wi-Fi access points. Talk to your local Wi-Fi administrator to find out what you need to get the Control Hub as an approved network.

• Does the the Driver Hub connect to the Control Hub until a mechanism is run?

  • Certain mechanisms draw enough power from the Control Hub to put a strain on the battery. If you notice a drop in displayed voltage when you start a code, or when a particular mechanism is run, this may be indicative of a brown out condition. Other indicators include:

    • The Driver Hub throwing errors about power to the system

    • The Driver Hub making a disconnect sound

    • The voltage on the Driver Hub showing 9 volts or lower when running code

    • Motors running at lower speeds then what they have been set to run

  • To remedy this issue check out our instructions on proper battery care.

If you are still experiencing connection issues, once you have gone through the flowchart and worked on addressing the potential root of connection issues describe in the list above, start looking for patterns in the behavior. How often does this behavior appear? Are there certain things that happen around the same time the disconnects happen? The following list provides some ideas on what sort of patterns you might see:

• The Driver Hub connects to Wi-Fi and the Control Hub when a team member takes it home but doesn't connect consistently at school.

• The Driver Hub connects to the Control Hub until you start driving the robot around.

Performing a Factory Reset to the Driver Hub.

1. Power on the Driver Hub and find the Settings application.
2. Click Settings and scroll down to System, then tap System.

3. Once you are in System, find "Reset Options".

4. Press "Erase all data (factory reset)". Keep in mind this will erase all applications, files, images, and anything else you have stored on your Driver Hub.

Still Need Assistance?

Contact REV Support with details of the troubleshooting information you have collected such as the answers to the questions above and the outcome of your troubleshooting thus far. It will also help to send logs or other diagnostic data to REV Support.

If you encounter any of these issues below, please email support@revrobotics.com

• Device freezes on boot, then restarts the boot process in a loop

• Device freezes on boot and never gets into the OS, even after a hard reboot

• Charging and Power issues persist after multiple battery calibrations

Wi-Fi immediately turning off on the Driver Hub

If you are having trouble getting the Wi-Fi to stay on or turn on, it is likely that your Driver Hub is experiencing a failure of the built-in Wi-Fi chip. This most often presents as the Driver Hub’s Wi-Fi no longer functioning and also not staying turned “on” under the device’s settings.

Since this failure is caused by physical damage to the Wi-Fi Chip, we highly suggest using the Driver Hub Repair Service (REV-31-1596-RFB) to purchase a repair for your Driver Hub. If you are still within the warranty period, or have any questions about the Repair Service, please email our support team at support@revrobotics.com.

The following questions consider common indicators of issues seen in the Control Hub. Think about the potential indicators your Hub is currently exhibiting and consider the following questions:

Can't Connect the Control Hub to the REV Hardware Client

External factors, such as local Wi-Fi environment, play a part in the ability to establish or maintain a connection between a Control Hub and a computer. Like all aspects of of troubleshooting its important to isolate an issue by asking questions and discovering the answers! As you work on troubleshooting consider the following questions:

• What is your local Wi-Fi environment like?

  • Local Wi-Fi environment effects the consistency of a connection to the Control Hub. Use a Wi-Fi analyzer to check the local environment for channels that are cluttered with Wi-Fi networks. Change the Control Hubs Wi-Fi channel to a channel with the least amount of overlap with other networks.

• Are you connected to another Wi-Fi network?

  • The Control Hub produces a non internet Wi-Fi connection. Settings on the individual computer may cause the device to jump to a local, remembered network that produces an internet connection.

• Are you in a school or a place of business?

  • In addition to the amount of local networks in an environment its important to understand what those local networks are capable of. For instance, some school districts have security measures in place that block unauthorized Wi-Fi access points. Talk to your local Wi-Fi adminstrator to find out what you need to get the Control Hub as an approved network.

Contact REV Support with details of the troubleshooting information you have collected such as the answers to the questions above and the outcome of your troubleshooting thus far. It will also help to send logs or other diagnostic data to REV Support.

Driver Hub Won't Connect

External factors, such as local Wi-Fi environment, play a part in the ability to establish or maintain a connection between a Control Hub and a Driver Station device. Like all aspects of of troubleshooting its important to isolate an issue by asking questions and discovering the answers! As you work on troubleshooting consider the following questions:

• Is your system operating on a 2.4 GHz band or 5GHz band?

  • REV recommends, if you have a dual band Driver Station device, that you operate on the 5GHz Wi-Fi band. Check out the Updating Wi-Fi Settings section to learn more about making this switch.

• What is your local Wi-Fi environment like?

  • Local Wi-Fi environment effects the consistency of a connection to the Control Hub. Use a Wi-Fi analyzer to check the local environment for channels that are cluttered with Wi-Fi networks. Change the Control Hubs Wi-Fi channel to a channel with the least amount of overlap with other networks.

• Are you in a school or a place of business?

  • In addition to the amount of local networks in an environment its important to understand what those local networks are capable of. For instance, some school districts have security measures in place that block unauthorized Wi-Fi access points. Talk to your local Wi-Fi administrator to find out what you need to get the Control Hub as an approved network.

• Does the the Driver Station connect to the Control Hub until a mechanism is run?

  • Certain mechanisms draw enough power from the Control Hub to put a strain on the battery. If you notice a drop in displayed voltage when you start a code, or when a particular mechanism is run, this may be indicative of a brown out condition. Other indicators include:

    • The Driver Station throwing errors about power to the system

    • The Driver Station making a disconnect sound

    • The voltage on the Driver Station showing 9 volts or lower when running code

    • Motors running at lower speeds then what they have been set to run

  • To remedy this issue check out our instructions on proper battery care.

If you are still experiencing connection issues, once you have gone through the flowchart and worked on addressing the potential root of connection issues describe in the list above, start looking for patterns in the behavior. How often does this behavior appear? Are there certain things that happen around the same time the disconnects happen? The following list provides some ideas on what sort of patterns you might see:

• The Control Hub connects fine when a team member takes it home but doesn't seem to like to connect at school.

• The Control Hub connects fine until you start driving the robot around.

Contact REV Support with details of the troubleshooting information you have collected such as the answers to the questions above and the outcome of your troubleshooting thus far. It will also help to send logs or other diagnostic data to REV Support.

Status LED is Solid Blue for Longer than 30 Seconds

The status LED on the Control Hub is similar to a check engine light on a car. A solid blue status LED indicates the Robot Controller is not communicating to the I/O of the Control Hub, but not what the root cause is. Updating the Control Hub to the latest version of all the software is a first step to resolving this issue, listed below are two ways to update.

Using the REV Hardware Client

The REV Hardware Client is software designed to make managing REV devices easier for the user. This Client automatically detects connected device(s), downloads the latest software for those device(s), and allows for seamless updating of the device(s). Using the REV Hardware Client allows you to perform any required updates that may be needed to recover your Control Hub. The Hardware Client can also be used to Send Diagnostic Data to REV.

Using Android Studio

If you use Android Studio for coding you will need to update your Robot Controller application by creating a new Android Studio project with the most recent version of the Robot Controller APK. Information on this process can be found in FTC Wiki Android Studio Tutorial.

XT30 Pins are Compressed

The most common cause of a loose or wiggly XT30 port is compressed pins within the male XT30 connector on your Hub. Each pin of the male XT30 connector is made of 4 tines that should have a small amount of space between them. In the image below, the pin on the top has the correct amount of space and the bottom one is visibly compressed, however, an XT30 pin can still be too compressed even if there is visible space.

To help repair compressed XT30 pins, we recommend using an X-ACTO Knife or similar very thin blade to slightly separate the tines. Please use extreme caution when doing this repair as expanding the tines too far can cause the XT30 connector to not fit.

After slightly separating the tines, the male and female XT30 connectors should have a more secure connection.

Still Need Assistance?

Contact REV Support with details of the troubleshooting information you have collected such as the answers to the questions above and the outcome of your troubleshooting thus far. It will also help to send logs or other diagnostic data to REV Support.

Being able to connect to the Robot Controller Console, connect a Driver Station to a Control Hub, and the basics of wiring different actuators and sensors is just the start!

This section focuses on the next steps for using the REV Control System, including getting started with programming and best practices for managing the Control Hub and Slim Batteries.

Getting Started with Programming

Now that the Control Hub is setup, it is ready to start programming to control a robot.

Hello Robot, available for and , will walk you through the basics of getting started moving motors, using sensors, and programming a basic drivetrain!

Before you program:

In order for the Control Hub to properly communicate with hardware components, you must perform a two part process known as hardware mapping. One of the most important, and commonly forgotten steps, when getting started programming is the creation of the configuration file, which is the first part of the hardware mapping process.

A properly created configuration file, defines each hardware component with a unique name and a port type and number. After attaching hardware components to the Hub, use the Driver Station application to create a configuration, before beginning to program.

Adding a Expansion Hub

Depending on the application more motor, sensor, or servo ports maybe needed. If your robot needs more motors adding an Expansion Hub might be necessary. Adding an Expansion Hub adds the same amount of hardware ports as one Control Hub (an additional four motor ports, six servo ports, and all the sensor ports) to the system.

Managing the Control Hub

The Control Hub and Expansion Hub are field upgradable devices. When new software is released with new features, bug fixes, and season specific changes users can update the device themselves. Checking for software updates at the start of September and then about every 6-8 weeks is recommended.

Slim Battery Best Practices

All rechargeable batteries have a finite lifespan. Factors that affect lifespan include the number of discharge/charge cycles and the average loading of the battery. The following best practices can help maximize the lifespan of your battery:

• Charge rate

  • Minimum: 1.5A

  • Maximum: 3.0A

  • Recommended: 1.8A or 2.0A

• Do not overcharge

  • Disconnect the battery from the charger once it indicates a full charge.

  • Typical charge time does not exceed 2 hours.

  • Do not charge a battery that hasn't been discharged significantly.

    • For example, running the robot under minimal load for a few minutes will not significantly discharge the battery.

• Minimum no-load voltage: 9.0V

  • Discharging the battery past 9.0V can reduce the lifespan of the battery and can permanently damage the cells.

  • Periodic dips below 9.0V when under load is expected and OK.

    • For example, don't forget to unplug your battery after you are finished running the robot and don't run your robot until it completely stops responding!

• Temperature

  • Let the battery cool before and after charging.

  • The battery may feel warm after heavy loading or after charging. This is normal.

The REV Robotics Expansion Hub () is a low-cost educational device that can communicate with any computer (commonly the or an Android Phone) to provide the interfaces required for building robots and other mechatronics. The Expansion Hub was purpose built to stand up to the rigors of the classroom and competition field. It features a mature firmware designed for basic and advanced use cases with the ability to be field upgraded in the future.

The IO ports of the Expansion Hub are identical in specification to the Control Hub. Within this documentation, many sections may refer to the Control Hub, but the connections are the same for the Expansion Hub.

The REV Robotics Expansion Hub is an approved device for use in the FIRST Tech Challenge and FIRST Global.

Specifications

The following tables provide the operating and mechanical specifications for the Expansion Hub.

Input Power Specifications

Motor Port Specifications

Encoder Port Specifications

Digital Port Specifications

Analog Port Specifications

I2C Port Specifications

Servo Port Specifications

+5V Power Port Specifications

Mechanical Specifications

The REV Robotics Control Hub () is an affordable all in one educational robotics controller that provides the interfaces required for building robots, as well as other mechatronics, with multiple programming language options. The Control Hub was designed and built as an easy to use, dependable, and durable device for use in classroom and the competition. It features an Android operating system, built-in dual band Wi-Fi (802.11 ac/b/g/n/w), and a mature software package designed for both basic and advanced use cases. When the Control Hub software is updated with new features, the controller can receive a "field upgrade," through an update process that is fast and simple.

The Control Hub is an approved device for use in FIRST® Global and FIRST Tech Challenge.

Specifications

The following tables provide the operating and mechanical specifications for the Control Hub.

General Specifications

Input Power Specifications

Motor Port Specifications

Encoder Port Specifications

Digital Port Specifications

Analog Port Specifications

I2C Port Specifications

Servo Port Specifications

+5V Power Port Specifications

Mechanical Specifications

The Control () and Expansion Hub () were designed with a number of protection features built into the device. These include the following:

• Reverse battery input protection

• Electrostatic discharge (ESD) protection on all connections

• Over-current protection on all power buses

  • Digital I/O bus

  • I2C bus

  • Analog bus

  • USB

  • Servo bus per pair (0-1, 2-3, 4-5)

  • Encoder bus

• Over-current monitoring for individual Motor Channels

• Keyed and locking connectors

• Fail-safe mode at communication loss

The SPARKmini Motor Controller () is an inexpensive in-line brushed DC motor controller designed to give FIRST® Tech Challenge teams more bang for their buck. It offers the same performance characteristics as the REV Control Hub () or Expansion Hub () motor ports in a small 60mm x 22mm footprint. Now FTC teams can add a SPARKmini Motor Controller to utilize more than four DC motors from a single Hub in a space-efficient package.

Power and Motor Connections

The SPARKmini has three integrated wires with connectors dedicated to power, control, and the motor; one for power, one 3-wire servo-PWM connector for control, and one connector for the motor. The figure below shows each of these connections.

Servo-PWM Input

A motor’s speed is controlled by varying the voltage that is applied to it. The SPARKmini’s output voltage can be controlled by sending it an extended-range servo-PWM pulse. The extended 500µs to 2500µs servo-pulse corresponds to full-reverse and full-forward rotation with 1500µs as the neutral position (no rotation). The pulses are proportionally related to the motor output duty cycle, therefore variable speed can be achieved with pulses in between the extremes. The following table describes the pulse ranges in more detail.

Table - Control Signal Pulse Ranges

Zero-Power Behavior

When the SPARKmini is receiving a neutral command it will not provide any power to the attached motor. There are two options for how the SPARKmini handles this zero-power state:

Brake - Motor terminals are shorted to each other to dissipate electrical energy, effectively braking the motor. Coast - Motor terminals are disconnected, allowing the motor to spin down at its own rate.

The zero-power behavior can be selected via a switch located towards the center of the SPARKmini housing, shown in Figure 2. Each mode can be selected by sliding the switch to either the Brake (B) or Coast (C) positions.

The SPARKmini will indicate whether it is in Brake or Coast mode via the Status LED, located in the center of the housing, whenever it is outputting zero-power. Solid or flashing blue indicates Brake Mode while solid or flashing yellow indicates Coast Mode. See the LED Status Codes section for more details.

LED Status Codes

Specifications

Most Common Issues

Battery Installation

To install the battery, place it with the REV Logo facing out and the -/+ located near the contacts for the device. Add on the rear door and screw in using the included M3 hardware.

Battery Calibration

We are aware of some Driver Hubs that were shipped from the factory without having their batteries properly calibrated. If you are experiencing power issues such as trouble charging or being unable to power on the device, try the following:

1. Plug Driver Hub into a charger without battery (Please use the charger that came with the Driver Hub to ensure a proper calibration)

2. Turn on Driver Hub and verify that the Driver Hub reports 100% battery charge. If the Driver Hub does not report 100% charge, you may be using a PD charger and not the one that came with the Driver Hub.

3. Install battery into Driver Hub while device is still on and charging

4. Charge for at least 8 hours and do not remove battery or charge cable

5. Remove Driver Hub from Charger

6. Hard Reboot

Battery Verification

After completing a battery calibration, use these steps to verify that your battery is functioning as expected.

1. Place the battery in a Driver Hub and verify that the Driver Hub turns on.

3. Take note of the indicated battery charge level, charge the Driver Hub for 10 minutes, and verify that the battery charge level increased.

4. If you have the time, perform a full charge/discharge cycle with the battery to verify that the battery behaves normally.

Foam Tape Installation

1. Cut foam tape into small pieces, approximately 2 inches or less long. The foam tape recommended is approximately 1/4 inch or less wide and 1/16 inch or less thick

2. Foam tape will be applied inside the battery case, opposite battery contacts and below the ridge that the battery door sits within.

3. Stick foam strip in the middle, both side to side and top to bottom, of the vertical surface opposite the battery contact switch.

4. Press foam strip down firmly to make sure it sticks.

5.1 Insert battery by inserting top of battery towards foam, and gently squeezing battery towards foam with thumb until battery can easily drop into battery case.

5.2 Continue to push the battery down until it is flush in the case.

6. Done

Battery Lockout Recovery

The Driver Hub can enter a "safe" mode intended to protect the battery. This safe mode, also referred to as a battery lockout, keeps your battery and Hub safe by preventing the battery from overcharging and/or keeping the Driver Hub on continuously. This most often happens when the Driver Hub’s battery charge is too low or the device has not been charged for a long period of time.

Symptoms of this lockout mode include: To get the Driver Hub out of the Safe Mode, please follow these steps:

• The Driver Hub only turning on while plugged to the USB without the battery installed.

• The Driver Hub appearing to not charge the battery after being connected for long periods of time.

• The Driver Hub not turning on with the battery installed and the USB connected.

• The Driver Hub not turning on, but the red Status LED lighting up while on USB.

2. Let the battery charge for 5 minutes then unplug the Driver Hub. Wait just a moment then plug the Hub back in.

3. Check to see if the Driver Hub is out of lockout by pressing the power button while the Driver Hub is charging.

   • If the "Battery charging icon" (red or white) appears on the screen proceed to Step 4.

   • If you do not see the battery charging icon, please repeat Step 2. Typically, it takes 4-5 cycles of short charging to recover a Driver Hub from this lockout state.

Still Need Assistance?

Contact REV Support with details of the troubleshooting information you have collected such as the answers to the questions above and the outcome of your troubleshooting thus far. It will also help to send logs or other diagnostic data to REV Support.

If you encounter any of these issues below, please email support@revrobotics.com

• Device freezes on boot, then restarts the boot process in a loop

• Device freezes on boot and never gets into the OS, even after a hard reboot

The following sections, "," provides common indicators of issues seen in the Expansion Hub. Think about what the potential indicators your Hub is currently exhibiting and consider the following questions:

• Did you perform a firmware update before the Hub began to have issues?

• What is the behavior of the Status LED on the Expansion Hub?

• Is the Driver Station showing an error message 'Cant find the Expansion Hub Portal"?

• Did the Robot Controller app open when you plugged in the RC phone and gave power to the Hub?

• Are you experiencing issues with communication between a primary and secondary Hub?

Common Indicators and their Solution Steps

• The firmware update failed and the Hub is unresponsive

  • Try a

• The LED on the Expansion Hub is not lighting up

  • Try a

• The Hub is not being recognized or communicating with the phones

  • Try doing the

• There are

Issues Connecting Control Hub to an Expansion Hub

XT30 Pins are Compressed

The most common cause of a loose or wiggly XT30 port is compressed pins within the male XT30 connector on your Hub. Each pin of the male XT30 connector is made of 4 tines that should have a small amount of space between them. In the image below, the pin on the top has the correct amount of space and the bottom one is visibly compressed, however, an XT30 pin can still be too compressed even if there is visible space.

To help repair compressed XT30 pins, we recommend using an X-ACTO Knife or similar very thin blade to slightly separate the tines. Please use extreme caution when doing this repair as expanding the tines too far can cause the XT30 connector to not fit.

After slightly separating the tines, the male and female XT30 connectors should have a more secure connection.

Firmware Update

USB Serial Converter Check

1. Plug your Expansion Hub into a Windows PC

2. Open the Device Manager in Settings

3. Click the arrow next to Universal Serial Bus Controllers

4. Find USB Serial Converter under the menu

5. If this is not present there maybe a larger issue with your hub. Email support@revrobotics.com with details of the steps you have taken so far and any order numbers for the Expansion Hub (if you have them)

Expansion Hub Power Cycle

1. Unplug the USB from your RC phone

2. Power off the main robot switch (turn off 12V power from the Expansion Hub(s))

3. Wait a few seconds

4. Turn on the Main Robot Switch (supply 12V power to the Expansion Hub(s))

5. On your RC phone, press the square button and the swipe to close the FTC RC app

6. Plug your RC phone into the USB-- the FTC app should automatically open

   1. If the app doesn't automatically open, you do not have a good connection from the Expansion Hub to the Phone. Check your cables first, followed by the micro and mini USB connections.

Still Need Assistance?

Contact REV Support with details of the troubleshooting information you have collected such as the answers to the questions above and the outcome of your troubleshooting thus far. It will also help to send logs or other diagnostic data to REV Support.

The REV Robotics Control Hub () connector selection provides a robust high-density solution for the user. All connectors are keyed and locking except for the Servo, 5V auxiliary power, HDMI , and USB ports.

The REV Robotics Driver Hub () is a compact mobile computing device designed for interfacing with the Control Hub (REV-31-1595). The Driver Hub was designed and built as an easy to use, dependable, and durable device for use in classroom and the competition. It features an Android operating system, built-in dual band Wi-Fi (802.11 ac/b/g/n/w), and support for many off-the-shelf gamepads and HID devices connected through built-in USB ports. When the Driver Hub software is updated with new features, the device can receive a "field upgrade," through a fast and simple update through the .

The Driver Hub is an approved device for use in FIRST® Global and FIRST Tech Challenge.

Specifications

The following tables provide the mechanical specifications for the Driver Hub.

General Specifications

Mechanical Specifications

Charger Specifications

Please refer to the following guidelines in the event the Driver Hub charger must be replaced:

The REV Robotics Control Hub (REV-31-1595) and Expansion Hub (REV-31-1153) integrate a number of feedback sensors. Some of these are user accessible in the latest FTC Android Studio SDK, but others are not yet directly user accessible. These sensors are in some cases also used by the Control Hub and Expansion Hub for internal safety monitoring.

• Battery Voltage Monitoring [Accessible]

• Integrated 6-axis IMU [Accessible]

  • Bosch BHI260AP 6-axis absolute orientation sensor

    • Control Hubs shipped before September 2022 instead feature a BNO055 9-axis IMU

    • Expansion Hubs shipped before December 2021 include a BNO055 9-axis IMU

    • Expansion Hubs shipped AFTER December 2021 do not have an IMU

  • Internally connected to I2C port 0 and configured to address 0x28

• Current Monitoring

  • Battery [Accessible]

  • I2C Bus [Accessible]

  • Digital Power Bus [Accessible]

  • Servo Power Bus [Not Accessible]

• Per Motor Channel Current Monitoring [Accessible]

Version 1.1.3 - Latest Version

• Adds support for new alternative built-in BHI260AP IMU on Control Hub

• Improves reliability of the Wi-Fi access point monitoring feature

Download Control Hub OS Version 1.1.3

Version 1.1.2

• Adds support for Auto Channel Selection, where the Control Hub will pick the least busy Wi-Fi channel on the selected Wi-Fi band when it starts up

• Migrates all users to Auto Channel Selection on the 5 GHz band by default.

  • If you find that you are unable to connect to the Control Hub after updating, you should perform a Wi-Fi Factory Reset by holding down the Control Hub's button as it boots, until you see a colorful light sequence. That will reset the Wi-Fi settings and switch to the 2.4 GHz Wi-Fi band.

• Allows switching the Wi-Fi band between 2.4 GHz and 5 GHz by holding down the Control Hub's button when the hub has been booted for at least 20 seconds

  • If version 5.5 or later of the Robot Controller app is installed, the Control Hub's light will blink magenta when the band is switched to 5 GHz, or yellow when the band is switched to 2.4 GHz.

• Continuously monitors the Wi-Fi access point status, and will attempt to restart it if it goes down for any reason

• Continuously monitors the Robot Controller app, and restarts it if it crashes or hangs (requires version 6.1 or later of the Robot Controller app)

• Allows the Robot Controller app to access the current Wi-Fi band and channel

• Always backs up the FTC Robot Controller app data before it is uninstalled, in order to preserve Wi-Fi settings

• Improves Wi-Fi reliability

• Prevents issue that could cause device to boot into recovery mode

• Enables use of mouse button in recovery mode

Download Control Hub OS Version 1.1.2

Version 1.1.1

• Fixed bug where Wi-Fi access point would sometimes fail to start after an Operating System update

• Stopped the FtcAccessPointService UI auto-starting on boot

• Allowed Wi-Fi beacon rate to be changed by the FTC Robot Controller app

Version 1.1.0

• Improved reliability of making changes to Wi-Fi access point settings

• Updated to latest Realtek Wi-Fi driver

• Increased Wi-Fi beacon rate to 6mbps, which reduces congestion when many Control Hubs are being used in an area

• Enabled 802.11w, which prevents Wi-Fi deauthentication attacks when the Control Hub is used with a client device that also supports 802.11w

• Added WifiLog.txt file for debugging and disconnection analysis

• Improved reliability of FtcAccessPointService UI (accessed through an HDMI monitor)

• Added 5 GHz channels to FtcAccessPointService UI

• Ensured app data is not lost when installing a Robot Controller with a different signature via the Manage webpage

• Fixed issue where Wi-Fi SSID would sometimes be AndroidAP

Source Files for Control Hub OS:

• Linux Kernel Source

• U-Boot Source

Version 1.8.2 (Latest Version)

• Improved USB recovery in case of fault event (e.g. ESD fault)

• Improved DC motor output linearity

• Improved closed-loop control modes

• Improved I2C speeds

• Minor bug fixes

Download REV Hub Firmware Version 1.8.2

Version 1.7.2

• Fixes a bug where encoder counts would occasionally reset.

Download REV Hub Firmware Version 1.7.2

Version 1.7.0

• Fixes a bug where some I2C sensors can lock up the bus causing other additional performance issues.

• Added new status LED blink code:

  • Blinking orange indicates the Expansion Hub is only powered over USB. In other words, turn on your main power switch!

• Other minor performance tweaks.

Download REV Hub Firmware Version 1.7.0

Version 1.6.0

• Original Release

Download REV Hub Firmware Version 1.6.0