Mini Driver

Overview

The Mini Driver Robot Controller [Product Link] by DAGU [Link] is equivalent in functionality to an Arduino NG, Motor Driver Shield, Servo Shield, and an ISP Programmer combined.

Features

Mini Driver Robot Controller by DAGU
Mini Driver Robot Controller by DAGU
  • ATMEGA8 @ 16Mhz with Arduino boot loader.
  • “Arduino NG or older with ATMEGA8” in the Arduino IDE.
  • Onboard 5V regulator.
  • Power supply voltage: 5-9V
  • Dual Channel DC Motor Driver up to 2A peak current per channel.
  • Supports up to 8 Servos.
  • SMD version of ATMEGA8.
  • Battery Level monitoring available on pin A7 when >5V supplied.
  • A6 is accessible through a solder pad in the back if needed.
  • Built in LED connected to D13.
  • Master On-Off switch.

Description

The DAGU Mini-Driver control board is a low-cost Arduino-based miniature robot control board that is software compatible with the Arduino NG, with a number of add-ons for all the basic functions needed to get small and medium-sized robot projects started quickly. Ideal for embedded projects, designed for students, hobbyist, and educators, the controller includes an ATMEGA8 (5V @ 16Mhz) with Arduino boot loader, Dual Channel DC motor controller (up to 2.5Amps per channel) and can drive up to 8 Servos. This controller is used in the Dagu Doodle Bot.

With a built in dual-FET “H” bridge and the ability to drive servos directly from the battery, this board makes for a great motor or servo driver. Using built-in code of the Arduino IDE, the Mini Driver can also be used as an ISP programmer for re-burning bootloaders or bypassing the bootloader completely.

Programming

The Mini Driver can be programmed using the Arduino IDE with the board type set as “Arduino NG or older w/ ATmega8”. The built in USB interface allows the controller to be programmed using a standard A-to-Mini-B USB cable [Product Link].

Do not attach motors or sensors while programming the board. Always program the board, disconnect it from the USB port of the computer, connect motors or sensors that you want to connect and then connect the board to an external power source.

Wireless Communications

The serial I/O pins D0 and D1 are broken out into a 4 pin female header along with +5V and GND. This allows wireless transceivers such as an Xbee or Bluetooth module to be connected. Deviced connected to D0 and D1 must be removed while uploading a new program using the USB interface.

Power Supply

The Mini Driver is a low voltage device and so input voltage should be between 5V and 9V. Voltages higher than 9V may damage the controller. A reverse polarity protection circuit will prevent damage if the battery is connected the wrong way but short circuit currents higher than 5.8A can cause permanent damage. Maximum current from the 5V regulator should be limited to 500mA.

Mini Driver Robot Controller by DAGU - Pin Description
Mini Driver Robot Controller by DAGU – Pin Description

Dual FET “H” Bridge

A dual “H” bridge allows the Mini Driver to control two D.C. brushed motors with a stall current as high as 2.5A per motor. The voltage to the motors is supplied directly from the battery. When not required, the dual “H” bridge can be isolated from the controller by removing 4 jumpers. This then makes digital pins D7, D8, D9 and D10 available for other uses.  Connect the left motor to the two pin male header ML and the right motor to MR. The motors are always powered directly from the battery. Direction of the left motor is controlled by D7, while D9 is its speed control (PWM) pin. Similarly,  direction of the right motor is controlled by D8, while D10 is its speed control (PWM) pin. If the motor turns in the wrong direction then swap the connections on the ML or MR headers.

Digital (Servo) Pins

Digital pins D2, D3, D4, D5, D6, D11, D12 and D13 are terminated with servo compatible 3 pin male headers. The +V rail for these pins can be set to +5V or Battery. When +V is set to +5V, digital sensors such LDR Sensor Module [Product Link], Infrared Sensor Module [Product Link], PIR Sensor [Product Link] can be powered from the 5V regulator. Small servos may also be powered from the 5V regulator as long as they do not draw too much current. When +V is set to Battery, servos like the SG90 Micro Servo [Product Link] (which draws approximately 500mA) or the MG90 Micro Servo [Product Link] can be powered directly from the battery. To power both, +5V devices as well as servos, power the +5V device using the power pins next to the analog inputs.

Analog Pins

Analog pins A0 to A5 are terminated with a 3 pin header for powering sensors with the +V rail is always at +5V. A6 is terminated as a small solder pad on the back of the board while A7 is hard wired into a voltage monitor which can read battery voltages as high as 10V.

Analog Pins as Digital

Analog pins A0 – A7 can also be used as digital pins D14 to D21, although D21 should not be used as it is hardwired as a voltage monitor. When used as digital pins, servos can be connected to D14-D19 if necessary.

Pullup Resistors

Internal 20K pullup resistors are available on the pins which can be activated by writing a digital 1 (HIGH) to that pin while it is configured as an input pin. This is ideal for reading switches connected between the input pins and GND.

Special Function Pins

  • D0 & D1 are the serial port RX and TX pins.
  • D2 & D3 are the external interrupt pins.
  • D9, D10 & D11 are PWM capable pins (disabled when using the Servo library).
  • D10, D11, D12 and D13 connect to the ISP socket.
  • D13 is output by default.
  • A4 & A5 are the SDA and SCL pins for the I2C interface.

As a Programmer

Tutorial on how to ‘Make an Arduino into ISP programmer’ [Link]

Downloads

Drivers for CP2102 interface [Link]

When Doodle-Bots Collide [Video Link]

Possible Application Areas

This board can be used with any sensor or motor that conforms to the voltage and current range of the board. Ideal for creating mobile 2-wheel drive robots, some application ideas are:
1. Light Detecting Robot [Link].
2. Line Follower/Edge Avoider Robot [Link].
3. Object Detecting Robot [Link].
4. Line Follower with Object Detecting Robot [Link].

Did you create a project using this product? Leave details/links below!

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