Arduino Robot
Overview
The Arduino Robot is the first official Arduino on wheels. The robot has two processors, one on each of its
two boards. The Motor Board controls the motors, and the Control Board reads sensors and decides how to
operate. Each of the boards is a full Arduino board programmable using the Arduino IDE.
Both Motor and Control boards are microcontroller boards based on the ATmega32u4 (datasheet). The
Robot has many of its pins mapped to on-board sensors and actuators.
Programming the robot is similar to the process with the Arduino Leonardo. Both processors have built-in
USB communication, eliminating the need for a secondary processor. This allows the Robot to appear to a
connected computer as a virtual (CDC) serial / COM port.
As always with Arduino, every element of the platform – hardware, software and documentation – is freely
available and open-source. This means you can learn exactly how it's made and use its design as the starting
point for your own robots. The Arduino Robot is the result of the collective effort from an international
team looking at how science can be made fun to learn. Arduino is now on wheels, come ride with us!
Control Board Summary
Microcontroller
ATmega32u4
Operating Voltage
5V
Input Voltage
5V through flat cable
Digital I/O Pins
5
PWM Channels
6
Analog Input Channels
4 (of the Digital I/O pins)
Analog Input Channels (multiplexed)
8
DC Current per I/O Pin
40 mA
Flash Memory
32 KB (ATmega32u4) of which 4 KB used by bootloader
SRAM
2.5 KB (ATmega32u4)
EEPROM (internal)
1 KB (ATmega32u4)
EEPROM (external)
512 Kbit (I2C)
Clock Speed
16 MHz
Keypad
5 keys
Knob
potentiomenter attached to analog pin
Full color LCD
over SPI communication
SD card reader
for FAT16 formatted cards
Speaker
8 Ohm
Digital Compass
provides deviation from the geographical north in degrees
I2C soldering ports
3
Prototyping areas
4
Motor Board Summary
Microcontroller
ATmega32u4
Operating Voltage
5V
Input Voltage
9V to battery charger
AA battery slot
4 alkaline or NiMh rechargeable batteries
Digital I/O Pins
4
PWM Channels
1
Analog Input Channles
4 (same as the Digital I/O pins)
DC Current per I/O Pin
40 mA
DC-DC converter
generates 5V to power up the whole robot
Flash Memory
32 KB (ATmega32u4) of which 4 KB used by bootloader
SRAM
2.5 KB (ATmega32u4)
EEPROM
1 KB (ATmega32u4)
Clock Speed
16 MHz
Trimmer
for movement calibration
IR line following sensors
5
I2C soldering ports
1
Prototyping areas
2
Schematic & Reference Design
EAGLE files for control and motor boards: arduino-robot-reference-design.zip
Power
The Arduino Robot can be powered via the USB connection or with 4 AA batteries. The power source is
selected automatically.
The battery holder holds 4 rechargeable NiMh AA batteries.
NB : Do not use non-rechargeable batteries with the robot
For safety purposes, the motors are disabled when the robot is powered from the USB connection.
The robot has an on-board battery charger that requires 9V external power coming from an AC-to-DC
adapter (wall-wart). The adapter can be connected by plugging a 2.1mm center-positive plug into the Motor
Board's power jack. The charger will not operate if powered by USB.
The Control Board is powered by the power supply on the Motor Board.
Memory
The ATmega32u4 has 32 KB (with 4 KB used for the bootloader). It also has 2.5 KB of SRAM and 1 KB of
EEPROM (which can be read and written with the EEPROM library).
The Control Board has an extra 512 Kbit EEPROM that can be accessed via I2C.
There is an external SD card reader attached to the GTFT screen that can be accessed by the Control Board's
processor for additional storage.
Input and Output
The Robot comes with a series of pre-soldered connectors. There are a number of additional spots for you to
install additional parts if needed.
All the connectors are labelled on the boards and mapped to named ports through the Robot library
allowing access to standard Arduino functions. Each pin can provide or receive a maximum of 40mA at 5V.
Some pins have specialized functions :
Control Board TK0 to TK7: these pins are multiplexed to a single analog pin on theControl Board's
microprocessor. They can be used as analog inputs for sensors like distance sensors, analog ultrasound
sensors, or mechanical switches to detect collisions.
Control Board TKD0 to TKD5: these are digital I/O pins directly connected to the processor, addressed
using Robot.digitalRead() and Robot.digitalWrite) functions. Pins TKD0 to TKD3 can also be used as
analog inputs with Robot.analogRead()
Note: if you have one of the first generation robots, you will see that the TKD* pins are named TDK* on
the Robot's silkscreen. TKD* is the proper name for them and is how we address them on the software.
Motor Board TK1 to TK4: these pins are named in software as B_TK1 to B_TK4, they can be digital or
analog input pins, and support Robot.digitalRead(), Robot.digitalWrite) and Robot.analogRead().
Serial Communication: The boards communicate with each other using the processors' serial port. A 10-
pin connector connects both boards carries the serial communication, as well as power and additional
information like the battery's current charge.
Control Board SPI: SPI is used to control the GTFT and SD card. If you want to flash the processor using
an external programmer, you need to disconnect the screen first.
Control Board LEDs: the Control Board has three on-board LEDs. One indicates the board is powered
(PWR). The other two indicate communication over the USB port (LED1/RX and TX). LED1 is also
accessible via software.
Both boards have I2C connectors available: 3 on the Control Board and 1 on the Motor Board.
Control Board Pin Mapping
ARDUINO
LEONARDO
ARDUINO ROBOT
CONTROL
FUNCTION
REGISTER
D0
RX
RX
RXD1/INT2
D1
TX
TX
TXD1/INT3
D2
SDA
SDA
SDA/INT1
D3#
SCL
PWM8/SCL
OC0B/SCL/INT0
D4
MUX_IN A6
ADC8
D5#
BUZZ
???
OC3A/#OC4A
D6#
MUXA/TKD4 A7
FastPWM
#OC4D/ADC10
D7
RST_LCD
INT6/AIN0
D8
CARD_CS A8
ADC11/PCINT4
D9#
LCD_CS A9
PWM16
OC1A/#OC4B/ADC12/PCINT5
D10#
DC_LCD A10
PWM16
OC1B/0c4B/ADC13/PCINT6
D11#
MUXB
PWM8/16
0C0A/OC1C/#RTS/PCINT7
D12
MUXC/TKD5 A11
T1/#OC4D/ADC9
D13#
MUXD
PWM10
CLK0/OC4A
A0
KEY D18
ADC7
A1
TKD0 D19
ADC6
A2
TKD1 D20
ADC5
A3
TKD2 D21
ADC4
A4
TKD3 D22
ADC1
A5
POT D23
ADC0
MISO
MISO D14
MISO,PCINT3
SCK
SCK D15
SCK,PCINT1
MOSI
MOSI D16
MOSI,PCINT2
SS
RX_LED D17
RXLED,SS/PCINT0
TXLED
TX_LED
HWB
HWB
Motor Board Pin Mapping
ARDUINO
LEONARDO
ARDUINO ROBOT
CONTROL
ATMEGA
32U4
FUNCTION
REGISTER
D0
RX
PD2
RX
RXD1/INT2
D1
TX
PD3
TX
TXD1/INT3
D2
SDA
PD1
SDA
SDA/INT1
D3#
SCL
PD0
PWM8/SCL
OC0B/SCL/INT0
D4
TK3 A6
PD4
ADC8
D5#
INA2
PC6
???
OC3A/#OC4A
D6#
INA1 A7
PD7
FastPWM
#OC4D/ADC10
D7
MUXA
PE6
INT6/AIN0
D8
MUXB A8
PB4
ADC11/PCINT4
D9#
INB2 A9
PB5
PWM16
OC1A/#OC4B/ADC12/PCINT5
D10#
INB1 A10
PB6
PWM16
OC1B/0c4B/ADC13/PCINT6
D11#
MUXC
PB7
PWM8/16
0C0A/OC1C/#RTS/PCINT7
D12
TK4 A11
PD6
T1/#OC4D/ADC9
D13#
MUXI
PC7
PWM10
CLK0/OC4A
A0
TK1 D18
PF7
ADC7
A1
TK2 D19
PF6
ADC6
A2
MUX_IN D20
PF5
ADC5
A3
TRIM D21
PF4
ADC4
A4
SENSE_A D22
PF1
ADC1
A5
SENSE_B D23
PF0
ADC0
MISO
MISO D14
PB3
MISO,PCINT3
SCK
SCK D15
PB1
SCK,PCINT1
MOSI
MOSI D16
PB2
MOSI,PCINT2
SS
RX_LED D17
PB0
RXLED,SS/PCINT0
TXLED
TX_LED
PD5
HWB
PE2
HWB
Communication
The Robot has a number of facilities for communicating with a computer, another Arduino, or other
microcontrollers. The ATmega32U4 provides UART TTL (5V) serial communication, which is available on
digital the 10-pin board-to-board connector. The 32U4 also allows for serial (CDC) communication over
USB and appears as a virtual com port to software on the computer. The chip also acts as a full speed USB
2.0 device, using standard USB COM drivers. On Windows, a .inf file is required. The Arduino software
includes a serial monitor which allows simple textual data to be sent to and from the Robot board. The RX
(LED1) and TX LEDs on the board will flash when data is being transmitted via the USB connection to the
computer (but not for serial communication between boards).
Each one of the boards has a separate USB product identifier and will show up as different ports on you
IDE. Make sure you choose the right one when programming.
The ATmega32U4 also supports I2C (TWI) and SPI communication. The Arduino software includes a Wire
library to simplify use of the I2C bus; see the documentation for details. For SPI communication, use the
SPI library.
Programming
The Robot can be programmed with the Arduino software (download). Select "Arduino Robot Control
Board" or "Arduino Robot Motor Board" from the Tools > Board menu. For details, see the getting started
page and tutorials.
The ATmega32U4 processors on the Arduino Robot come preburned with a bootloader that allows you to
upload new code to it without the use of an external hardware programmer. It communicates using the
AVR109 protocol.
You can bypass the bootloader and program the microcontroller through the ICSP (In-Circuit Serial
Programming) header; see these instructions for details.
Automatic (Software) Reset and Bootloader Initiation
Rather than requiring a physical press of the reset button before an upload, the Robot is designed in a way
that allows it to be reset by software running on a connected computer. The reset is triggered when the
Robot's virtual (CDC) serial / COM port is opened at 1200 baud and then closed. When this happens, the
processor will reset, breaking the USB connection to the computer (meaning that the virtual serial / COM
port will disappear). After the processor resets, the bootloader starts, remaining active for about 8 seconds.
The bootloader can also be initiated by double-pressing the reset button on the Robot. Note that when the
board first powers up, it will jump straight to the user sketch, if present, rather than initiating the
bootloader.
Because of the way the Robot handles reset it's best to let the Arduino software try to initiate the reset
before uploading, especially if you are in the habit of pressing the reset button before uploading on other
boards. If the software can't reset the board you can always start the bootloader by double-pressing the
reset button on the board. A single press on the reset will restart the user sketch, a double press will
initiate the bootloader.
USB Overcurrent Protection
Both of the Robot boards have a resettable polyfuse that protects your computer's USB ports from shorts
and overcurrent. Although most computers provide their own internal protection, the fuse provides an extra
layer of protection. If more than 500 mA is applied to the USB port, the fuse will automatically break the
connection until the short or overload is removed.
Physical Characteristics
The Robot is 19cm in diameter. Including wheels, GTFT screen and other connectors it can be up to 10cm
tall.