DC Motors

Let's start by taking a look at the ports on the HD Hex Motor and Core Hex Motor:

Each motor has a power and encoder port. Encoders are a form of sensor built into the motor that can send information back to the Control Hub to be used during programming. Specifically, these motors use incremental encoders, which count the number of revolutions or "ticks".

Power Wires

Red provides power while black serves as the ground. These wires are keyed, meaning they are meant to only attach to the motor and Control Hub one way as dictated by the clip on the connector.

In the event a power wire is connected backwards, the motor will spin the opposite expected direction!

Encoder Wires

Similarly to the power wires, red provides power while black serves as ground. The blue and white wires transmute signal between the motor and the Control Hub. These wires can be used with various sensors, not just motor encoders. The wires are keyed with the intention of only connecting one way.

When connecting the wires to both the motor and the Control Hub it should be a snug fit. Giving a small, light tug is a recommended practice to help wires are seated correctly.

On the servo end, the needed wire is already built-in. Unlike the motor wires, the power and ground are both black while white is the signal wire. On the Control Hub, signal is labeled as S.

These wires are not keyed meaning students will have to be careful which direction they are connecting them. While reversing the wire is unlikely to damage the servo, it will prevent it from working as expected.

Often times there may be a need to extend the built-in wire of the servo. To do so we can use a standard PWM cable.

The PWM wires available within the EDU Kit V2 are red for power, black for ground, and white for signal. When connecting a PWM cable to the servo's built-in cable, its easiest to focus on lining up the white signal wire to ensure the correct orientation.

Motor ports are located on the left side of the Control Hub and servo ports along the bottom.

For motors, each port pairs a power connector, the more square option, and an encoder connector, the more rectangular option.

The servo ports include a label to help with orienting the cable while connected since these are often not keyed.

When completing the , we tell the Control Hub what is connected and where.

It is NOT able to autodetect or correct once parts are wired meaning which port a motor is connected to DOES matter and should match the configuration.

For the testbed, the wiring layout is below:

After wiring your testbed, you will need to create a configuration before starting programming. Give this a try or review the section!

Recall that device names should be easily recognizable even, when creating test configs, to reduce future confusion. The names used from curriculum are below:

A testbed is a testing environment for hardware and software components. Testbeds are a fantastic tool to practice programming, troubleshoot parts, collect data, and continue to grow familiar with the EDU Kit V2.

Similar setups are used by professional engineers and companies as part of the development, quality control, and refinement processes! Depending on the end goal, these testbeds can be designed a variety of different ways. For example, if a company is gathering data on how much weight a part can handle, the testbed may be designed to continually move over a period of time while adding new amounts of weight.

In the Classroom:

Let's take a look at the testbed used within Unit 1 of the curriculum:

The goals of our testbed are:

• Provide a base frame that can be reused

• Allow mounting of 3 different kinds of actuators

• Demonstrate using actuator brackets for the different kinds of actuators

• Safely secure moving parts while creating our first OpMode

• Create an easy to move platform for organizing and storing student projects outside of class

This testbed can additionally be used for testing new actuators, Control Hubs, batteries, or sensors upon receiving them. This is a recommended best practice even if they may not be used yet!

Completing the Testbed build takes 20-30 minutes.

Wiring Diagrams are a visual aid that show where everything is wired in an electrical system. Students can think of them like a map showing the pathways between the Control Hub and each device location.

Right now our testbed uses a very simple wiring set up that's easy to track, but imagine if every motor and servo port was in use. That's 9 devices and sets of wires going across the robot before adding sensors!

Encourage students to create a wiring diagram for their own projects and to update it as they work. A blank template is below that includes the parts for the EDU Kit V2.

Wiring Tips

Along with wiring diagrams, here are a couple additional good practices to make encourage to prevent part damage and confusion while working with the robot.

Label Wires

Individual wires or wire pairs (ex: a motor's encoder and power wires), can be labeled using things like printed labels, small pieces of tape, colored zip ties, etc. It's recommended to label both ends for easy identification.

Labels may include port numbers, letters, device names, or whichever system works best for your classroom. When using something like colors, letters, or another code these can be added to the wiring diagram for the robot!

While designing a robot or build, it's important to plan ahead where electronics will sit and wires will run. It's best to keep the Control Hub easily accessible and where the lights can be viewed. For wires, consider potential pinch points and moving components where they may become caught or tangled.

Damaged wires may lead to parts not working as expected, causing shorts and damage, and pose a safety risk. While the robot is disconnected from power, encourage students to regularly check wires.

This should also be a first step while troubleshooting, both to check things are wired correctly, but also securely with proper wires.

Wires with exposed metal or fraying should be replaced.