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hMotor port

What is a hMotor?

RoboCORE is equipped with six hMotor ports.

The hMotor is intended to be used with a DC motor with encoder, but you don’t have to use the encoder interface if you have a standard DC motor. The hMotor interface is fully-compatible with LEGO® MINDSTORMS® sets (if you are worried about connector compatibility, please have a look here: hMotor and hSensor connectors).

Each hMotor port contains three basic elements:

An H - bridge for driving the DC motor (with or without encoder) or a stepper motor. It can also be used for driving other devices, but don’t forget about a PWM signal on the output and its limitations. The maximum average current for this port is 1.25 A, and the maximum peak current is 2A. The H-bridge is supplied from the RoboCORE power supply voltage (6 - 14V) and you can expect the same at the H-bridge output.

An auxiliary 5V supply output dedicated to supplying the encoder circuit. The maximum current is not limited for each port, but due to the 5 V line total current limit, it is recommended keeping the current below 50mA. If you are sure that the total 5 V current will not exceed 2A, you can go higher, up to 1A.

A quadrature encoder interface. If you don’t have any idea what this is, Wikipedia explains in an easy way: Incremental rotary encoder. The encoder interface is compatible with the majority of popular optical and magnetic encoders integrated with motors or sold separately.

hMotor pin Default function
1 Output A
2 Output B
3 Ground (GND)
4 +5V output
5 Encoder input A
6 Encoder input B

Supported motor types

LEGO® motor

RoboCORE is fully compatible with servomotors from LEGO® Mindstorms®. There are 3 types of LEGO® servomotors: motor from NXT/NXT2.0 kit and two types from EV3 kit. In fact, they are motors with quadrature encoder. Remember that LEGO® motors have 9V nominal voltage and when you supply RoboCORE with higher voltage, you should limit the PWM duty cycle.
To connect the LEGO® motor you do not need to solder anything, just use the adapter described here: hMotor and hSensor connectors.

DC motor with encoder

It has the same functionality as LEGO® motor, but is more robust (metal casing, mostly metal gears) and suitable for professional applications. Can be identified by 6 wires coming out from the encoder board.

DC motor without encoder

Of course, in many cases you don't need the encoder - e.g. if you need to drive wheels without sensing their position. In that case you can use a simple DC motor with gearbox. It can be identified by 2 wires coming out from the motor: Connecting a DC motor to the RoboCORE is very simple:

DC motor with limit switches

(to do)

Stepper motor

Connecting a bipolar stepper motor is also possible. In this case, you need two hMotor ports to drive one stepper motor.

robocore/hardware/hmotor.txt · Last modified: 2017/03/07 19:25 by zielmicha