Building a Robot from scratch involves choosing the right software and hardware. In the previous article, I explained the various libraries that help the robot with moving, detecting, navigating and controlling. Now this article explains the hardware side: The computers, the motors, the sensors with which to equip the robot. As in my previous article, this list is in all means not exhaustive, but lists components that I found during my research and find interesting to keep them here.

This article originally appeared at my blog.

Single Board Computers

A single board computer is the central component on which the robotic middleware is installed. It will provide the computing power necessary for forming the essential abstraction of your robot. It will also receive and coordinate the messages received from its individual parts. And its also the component receiving and parsing central control commands.

Raspberry Pi 4

1.5 Ghz Quad Core ARM Cortex-72 processor, 1-8 GB RAM
Products Page

Jetson Nano

1,43 GhZ Quad Core ARM A57, 4 GB RAM
128 Core Maxwell GPU
Product Page

BeagleBoard X15

1.5 Ghz ARM Cortex-A15, 2 GB RAM
Products Page

Microcontrollers

Microcontrollers are small computers that get programmed to perform a very specific task in your robot, like reading and processing sensor data or controlling your robot's motors.

Arduino UNO

ATmga328P MCU, 2KB RAM
Family of microcontrollers with manifold configuration
Wikipedia Page

Arduino Nano

ATmga328P MCU
Same features as the Arduino Nano, but compatible with breadboards and smaller in design
Wikipedia Page

Feather boards

Family of microcontrollers, very similar to Arduino, produced by the company AdaFruit
Wikipedia Page
List of products

Seeduino

ATmga328P MCU
Arduino compatible boards, that feature a Micro-USB connection and can seamlessly integrate with a number of other boards from the Grove module family
Product Page

Pocketbeagle

OSD3358 1GHz ARM, 512MB RAM
USB and MicroSD connectors
Product Page

NodeMCU v2

ATmga328P MCU, 128KB RAM
Arduino Compatible, built-in Wifi,
IoT plattform
Wikipedia Page

Argon Wifi Development Board

ARM Cortex-M4F 32-bi, 4 MB RAM
MicroUSB Connection
Product Page

Espressif Systems ESP8266

L106 32-bit RISC, 80KB RAM
Wikipedia Page

Espressif Systems ESP32

Tensilica Xtensa LX6 microprocessor, 520 KB RAM
Built-In WiFi, SD Card Reader
Successor to the ESP8266
Wikipedia Page

ST Microelectronics STM32

ARM Cortex-M4F / M7F
Family of Microcontrollers based on ARM
Provided as Arduino or Discovery Boards (for debugging purposes)
Wikipedia Page

Teensy 3.6

ARM Cortex M4 processor, 256KB RAM
Arduino compatible
USB and MicroSD connectors
Product Page

MSP430 Launchpad

Microcontroller Development Board
Product Page

Netduino N3 Wi-Fi

ARM Cortex M4 processor, 256KB RAM
Built-In WiFi, SD Card Reader
Wikipedia Page

Chassis

The chassis forms one of the robots main appearance: How it moves and interacts with the world. Here I just list the chassis types and link to concrete examples.

Motors

Motors serve different functions in your robot. Thinking bottom up, it starts with the movements on the ground, continuous to joints that move arms, and fine precision motors for grabbing objects. In this category, I will explain the different motor types and how they work. For an in-depth explanation, read this very detailed article.

Synchronous AC Motor

Stator produces a constant magnetic field that powers the rotor
Once accelerated, the motor produces a constant torque

Asynchronous AC / Induction

The stator produces a magnetic field which powers the rotor
Magnetic polarization in the stator change the motors torque

Brushed DC motor

Inside the stator, brushes apply electric current to a rotating set of magnets that in turn power the rotor
Were the first commercially applied electric motor
Types: Grouped by their RPM

Brushed DC Geared Motors

Improvement of the DC motor that comes with a set of intertwined gears to provide better torque and reduced speed
Types: Grouped by RPM

Brushless DC motor / Synchronous DC motor

Provide an alternating magnetic field inside the stator that power the rotor
Types

Brushless DC stepper motor

Provide an alternating magnetic field inside the stator that power the rotor, and divides the rotation into discrete steps
Types: Unipolar, Bipolar

Brushless DC Servo Motors

A special Brushless Motor that provides fine grained control of the rotor via an analogous or digital signal
Types: Nano, Micro, Slim Wing etc.

Sensors

Sensors allow the robot to investigate its environment. Data gets collected, translated, and processed. In this category, I just list the different sensor types and how they work.

Light

Photo resistor converts light intensity to electric resistance
Photovoltaic Cells convert solar radiation into electric current

Proximity

Infra Red Transceivers emit infra-red light and measure the light reflection
Ultrasonic sensors emit sound and measure the echo impulse
Laser emit lasers and measure the lasers reflection

Sound

Microphone

Images

Camera

Movements and Acceleration

Provided via motors and their controllers
Gyroscope

Environment

Temperature
Humidity
Smoke

Complete Kits

The last section contains a selection of complete robot kits that come with chassis, sensors, microcomputers and an instruction how to assemble everything into a functioning robot

Conclusion

In this article, I explained the various types of hardware that make up a robot. The "nervous system" of a robot are its SBC and MC, build on top of a chassis, and moves with motors. Sensors give the robot access to its environment, enabling it to process and act on external situations. The various example should provide you with a good overview about the many choices that you can make.

Robot Systems: Hardware Overview