Arduino Robot Exploded Diagram

Introduction to the Robot and diagram

As the diagram shows, the new Arduino Robot comprises of two microcontroller boards stacked one of top of the other and connected together by means of ribbon cable. At the base, complete with a pair of wheels, is the Motor Board and above it at the top is the Control Board.

Newcomers to electronic programming are advised to work with the Control Board only to start with, although as familiarity with the device grows, more functions can be obtained by working the Motor Board as well. Arduino Robot tutorial videos, which were produced jointly by RS Components and Arduino, are available to help new users get started with the device, from assembling it out of the box to programing it to carry out various tasks.

Between them, the two boards (both of which are built around the ATmega32u4 processor) enable the robot to manage a relatively large data load, which means it can sense physical objects in its environment accurately and execute a versatile range of actions.  The Arduino Robot can for example, avoid collisions by sensing an approaching object and switch course, literally “run away” from an object pursuing it, locate objects in a maze and, with its infrared sensors, accurately follow the course of lines or markings on a flat surface. It can even be converted into a dancing “disco bot”, gyrating to the rhythm bursting from its 8-bit jukebox. Again, the online Arduino robot tutorials provide clear advice and guidance on how to get the best out of the kit, although the project examples the device comes with are easily replicated - even by newbies.

The separate TFT screen must be fitted correctly in order for the device to work, and must have the enclosed SD card inserted into it before it is attached to the centre of the Control Board. The SD card is preloaded with sound and image files for the robot to read, and can be added to if the user wishes. Users will see that the screen bears blue text reading “SD Card” – the screen is positioned correctly when this text is on the same half of the board which bears the protruding circular speaker and the five-button keypad. Additionally, the Motor Board needs to be shielded from damage by clipping the supplied protective cover into place (it slots around the wheel apertures and is virtually impossible to fit incorrectly).

Although both boards can be connected to a computer via a USB port for programing, novices should programme only the Control Board until they are more familiar with programming. As soon as the Control Board is connected to a computer, a green LED (marker “PWR”) lights up. Beneath it, another LED (“LED1”) will flash several times, while five red LEDs (labelled LED1 to LED5) will light up on the Motor Board. Check the Arduino Robot tutorial videos for advice on installing the drivers. Once these have been successfully installed, the Robot is ready for programming and requires 4 AAA batteries as a power source.

 

Technical breakdown – key components on the board

The Control Board

To begin with the Control Board, the most prominent feature is the full colour LCD screen attached to the centre of the board inside the white disc area. Moving clockwise, at 2 o’clock on the edge of the white circular area is the speaker, while the two LEDs mentioned above can be found at 4 o’clock adjacent to and to the right of the five-key control pad. At 5 o’clock in the blue outer area of the board are two horizontal banks of five pins – the interboard connector pins, while at 6 o’clock the “brain” of the board is located just beyond the outer edge of the white inner circle – the ATmega32u4 processor. Moving clockwise from the processor by about five minutes will take one to the Serial Processor Interface (SPI)/In-circuit serial programming (ICSP) connector, which enables the two boards to communicate with one another. The Control Board SPI also controls the TFT screen and the SD card. An additional five minutes clockwise brings one to the device’s Reset Button, also located at the edge of with circular area.

The Robot’s 1 KB EEPROM memory chip can be found at approximately 7 o’clock in the blue circular area (this stores small but vital quantities of data while the device in unpowered). More or less adjacent to it, roughly midway between the EEPROM and the out edge of the disc, is the device’s power knob, which is actually a potentiometer (variable resistor) linked to an analogue pin. At almost 10 o’clock, the device’s means of orientating itself in its environment – the digital compass - can be found at the edge of the white area (it works by enabling the Robot to detect how many degrees it has deviated from due North). Directly above it are the Robot’s three 12C soldering ports (the Control Board’s additional 512 Kbits of EEPROM can be accessed from one of these ports).

The Control Board comes with several pre-soldered input and output connectors, each of which have their own unique label and provide access to Arduino functions because they are mapped via the Robot library to specific function ports. These I/O pins are located at evenly spaced intervals around the circumference of the Control Board (starting at midnight and in clockwise order, they are TK2, TK1, TKD3/4/5, TKO (below which is LED1 as described above), TK7 and at 6 o’clock, TK6. Proceeding clockwise are connectors TK5, TKD2, TK4, TK3 and TKD1. TKD connectors (0 to 5) are connected to the processor directly and are digital I/O connectors, while TK0 to 7 are connected to a single analogue pin on the ATmega32u4 processor. The latter receive analogue inputs from the devices ultrasound sensors and distance sensors, as well as the robot’s mechanical switches which register collisions. TKD0 to TKD3 also double as analogue connectors.

 

The Motor Board

Taking the centre of the small semi-circular indentation on the circumference of the Motor Board as 12 o’clock, a horizontal bank of five LEDs can be found just beneath, all of which function as the device’s infrared activity displays. At 3 o’clock and nine o’clock are the robots two wheels, with a 12C soldering port just below the 3 o’clock wheel. To the left of this port and horizontal with it is the robot’s interboard connector, while midway between 5 and 6 o’clock and just below it is the device’s 9V power jack for charging its rechargeable batteries. At 6 o’clock, the Motor Board’s on/off switch can be found, close to the circumference of the disc. The board communicates with the Control Board via the SPI/ISCP port, which is located near the circumference at approximately 7 o’clock. Just above it, midway between SPI/ISCP and the on/off switch, is the Motor Board’s reset button and to its right (and slightly above it) is the board’s own ATmega32u4 processor. There are two ball casters for additional stability located at 12 o’clock and 6 o’clock, and the central battery compartment houses 4 AAA rechargeable batteries (the device can also be powered via USB connection to a computer, with the Control Board receiving its power from the Motor Board’s power supply). Just below the 12 o’clock ball caster is a bank of five, horizontally-arranged IR sensors.

The four input/output pins (TK1 to TK4) can receive either analogue or digital signals.