Dual Hbridge

How to use the Dual Hbridge robot skill

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A movement panel for using a two-channel hbridge that uses DC motors. There is no speed control with this movement panel. The motors will be either ON or OFF.

An H-Bridge is an electronic circuit that enables a voltage to be applied across a motor in either direction. It's triggered by TTL signals from a microcontroller, such as an EZ-B. These circuits are often used in robotics and other applications to allow DC motors to run forward and reverse. A Dual H-Bridge (such as the EZ-Robot 2.5 Amp H-Bridge) controls two motors and can be connected to an EZ-B by four digital signal wires. 2 wires control each motor. This skill controls the movement of 2 motors.

This movement panel operates like the other movement panels and can be controlled by scripting or other skills that interact with it. Movement Panels are skills that move your robot forward, reverse, left, and right. The Movement Panel directions can be modified by other skills, such as camera, voice, script, joystick, and radar.

*Note: The I/O ports on an EZ-B cannot directly provide enough current to power a motor. Instead, use an EZ-B to control an H-Bridge that sends power to a motor. Think of the H-Bridge as a worker and the EZ-B as the boss. Also, note that this skill does not provide PWM speed. If you wish to control speed of your robot, use the Dual H-Bridge w/PWM skill.

Main Window

1. Movement Panel
These buttons will allow you to control the directional movement of the entire robot (left, right, forward, reverse, and stop).

Settings

1. Title Field
This field contains the title of the Dual H-Bridge skill. You can change it if you'd like. *Note: Changing the title here will also change the title in the controlCommand() associated with this skill.

2. Left Motor Control Buttons
These buttons allow you to change the signal ports for the Left motor.

3. Right Motor Control Buttons
These buttons allow you to change the signal ports for the Right motor.

Wiring Diagram

1) Connect Dual H-Bridge VCC to either your battery supply positive or EZ-B power (red) on pin D0
2) Connect Dual H-Bridge GND to either your battery supply positive or EZ-B power (black) on pin D0
3) Connect Dual H-Bridge IN1 to EZ-B Signal Pin D0 (white)
4) Connect Dual H-Bridge IN2 to EZ-B Signal Pin D1 (white)
5) Connect Dual H-Bridge IN3 to EZ-B Signal Pin D2 (white)
6) Connect Dual H-Bridge IN4 to EZ-B Signal Pin D3 (white)
7) Connect Dual H-Bridge OUTA to Left Motor Red Wire
8) Connect Dual H-Bridge OUTB to Left Motor Black Wire
9) Connect Dual H-Bridge OUTC to Right Motor Red Wire
10) Connect Dual H-Bridge OUTD to Right Motor Black Wire

*Note: The wiring diagram above depicts powering the Dual H-Bridge off of +V (direct from the input voltage); in this case, the switch onboard the Dual H-Bridge will have to be pushed down. Although, please note that some H-Bridge versions reverse the direction of the switch, and it will activate in the up position. You will know if the H-Bridge is on when the power LED on the Dual H-Bridge board lights up.

How to Use Dual H-Bridge

1) Physically connect the EZ-B to the Dual H-Bridge using the wiring diagram above as a reference.

2) Add the Dual H-Bridge Skill to your ARC project (Project -> Add Skill -> Movement Panels -> Dual H-Bridge).

3) In the Settings menu, select the ports you connected to the H-Bridge's INPUT Pins (D0, D1, D2, & D3, for example).

4) In the main window press the direction buttons to move your robot.

Video

Requirements

• 1 x EZ-B I/O Controller
• 1 x Dual H-Bridge
• 2 x DC motors

Resources

If your robot moves in the reverse direction, or spins instead of going straight, reverse the wire connections from the motor to the Dual H-Bridge. You could swap the signal sequence around in the skill's Settings menu if it's too difficult to reach these connections. Change [D0, D1, D2, D3] to [D1, D0, D2, D3] or [D0, D1, D3, D2] or [D1, D0, D3, D2]. You may need to try a few combinations to get it right. Sometimes it confuses us too!

There is a great community tutorial from Rich that you can find here.

Read more about how Movement Panels work here .