Meet ARPS-2

ARPS-2 is version two of my Arduino-compatible Robot Project Shield for Arduino UNO. ARPS-2 is a refinement of the original ARPS circuit and adds two additional Servo or I/O headers while repositioning the screw terminal to reduce the possibility of its solder pins shorting to the Arduino UNO Rev. 3's USB-B connector.

ARPS-2, like most of my circuits, is designed for beginner microcontroller education. ARPS-2 includes all of the common beginner electronic circuits on-board, enabling learners to focus on rapidly developing their programming skills instead of wiring and debugging breadboard circuits.

ARPS-2 is also fully simulated in TinkerCad, enabling teachers to interactively demonstrate its circuits and programs. ARPS-2 is designed to work best with Arduino UNO R4 Minima, but all of its hardware, with the exception of two pushbuttons, works with the Arduino UNO Rev. 3 circuits commonly found in many classroom STEM programs.

ARPS-2 goes beyond simple interface circuits by including a motor driver, SONAR module socket, IR demodulator, and break-away optical floor sensor modules that make it easy for learners to build line-following, object-sensing, or remotely-controlled robots, including simple classroom Sumo robots!

ARPS-2 build configurations

ARPS-2 is designed to be assembled by learners in stages using through-hole components. Partially assembling ARPS-2 enables students to start learning programming more quickly, and provides schools or makerspaces with the option to save costs by leaving unnecessary components un-populated. The multiple configurations also provide teachers with the option to offer students project differentiation and choice with just one circuit board and a common set of electronic parts.

Educational Starter configuration

The ARPS-2 Educational Starter configuration is equivalent to an Arduino circuit connected to a few pushbuttons and LEDs on a breadboard, but in a more reliable form. The Educational Starter configuration is quick to build and includes:

• Arduino header pins
• 4 user pushbuttons
• 4 user LEDs
• a piezo speaker
• optional TMP-36 or MCP9700A analog temperature sensor

The Educational Starter configuration allows students to learn programming fundamentals, including: input, output, variables, loops, sound, and creating and using simple functions. Adding the temperature sensor enables students to learn analog processing techniques.

Robot Starter configuration

The ARPS-2 Robot Starter configuration allows learners to add a variety of optional robot components, depending on the type of robot they plan to build. A motor driver IC and screw terminal strip allow ARPS-2 to control two DC motors in forward or reverse, driven from an external battery pack (or it can also drive 4 DC motors driven in one direction, or a single bi-polar stepper motor).

A 4-pin header socket is designed to hold an optional HC-SR04 ultrasonic SONAR distance sensor module to create object-sensing robots, and break-away optical sensor modules allow beginners to easily construct floor- and line-sensing robots. An optional IR demodulator enables the construction of remote-controlled robots (and learning about asynchronous data encoding and transmission), and on-board voltage divider resistors allow the robot to sense and monitor its power supply. Two extra I/O headers also allow servos to easily be attached:

• SN754410NE motor driver IC (a lower-cost L293D) and screw terminal strip
• 2 break-away optical floor and line sensor modules containing IR LEDs and phototransistors
• optional 4-pin header socket to mount an HC-SR04P 3.3V SONAR distance sensor module
• battery voltage divider resistors
• optional TSOP38238 IR demodulator to respond to IR control transmissions
• 2 3-pin servo headers

Custom ARPS-2 Configurations

If not built as a robot, ARPS-2's I/O headers can be used to connect up to eight external I/O devices including analog and I2C functionality. Turn ARPS-2 into an animatronic servo controller, a greenhouse monitor, room alarm system, NeoPixel driver, or many other kinds of beginner to intermediate microcontroller electronics projects.

How can I get started?

Bare ARPS-2 PCBs can be ordered from PCBWay, and ARPS-2 circuit kits are available on my website. A shared DigiKey parts list is linked below. A set of beginner lesson activities and project starter templates is shared on both GitHub and Tinkercad – see the links below.