Dual DC motor controller designed for Arduino, which enables the motor to be supplied with voltage in the 4.5 ... 28V range and power consumption in continuous operation of 2.6 A (5A at the top) of two DC motors. Polol 2520

Reflection sensor module with 1 QTRXL-HD optocoupler with analogue output. The module is powered by 2.9 ... 5.5V voltage, detects objects at a distance of up to 80mm. Pololu 4641

The A-Star 32U4 Mini ULV is a programmable module based on the ATmega32U4 from Atmel. Unlike competing products, it has an onboard switching step-up regulator that allows it to be powered efficiently from a 0.5 V to 5.5 V supply. Pololu 3102

This small synchronous switching step-down (or buck) regulator takes an input voltage from 4 V to 36 V and efficiently reduces it to 3.3 V. The board measures only 0.7″ × 0.7″ yet delivers a typical continuous output current of up to 2.6 A and features reverse voltage protection.

Injection-Molded Sprocket Set 8T Futaba

Vibration motor with a diameter of 8 mm and a height of 3.4 mm. It has a self-adhesive 3M backing for easy installation. Pololu 1637

The Step-Down D24V3AHV Buck Voltage Regulator module with adjustable output voltage in the range of 4-25V with a wide input voltage range of 4.5-42V and a maximum output current of 300 mA. Pololu 2102

A two-piece aluminum adapter for transmitting wheel drive to motors with a 4mm diameter shaft. Mounting screws and set screws included. Pololu 2672

Solarbotics GMB28 (GM2/GM8 Gear Motor Bracket, Laser-Cut Steel)

Aluminum Standoff: 3/8" Length, 2-56 Thread, M-F (4-Pack)

Module with 1 QTR type optocoupler with analog output. The module operates from 2.9 V to 5.5 V, detects objects at a distance of up to 30 mm. The sensor will be used in projects that require detection of changes in the ground, e.g. in linefollower robots. Pololu 4201

Aluminum Standoff: 1/2" Length, 2-56 Thread, M-F (4-Pack)

The compact (0.4″ × 0.5″) D24V5F12 synchronous buck voltage regulator takes an input voltage of up to 36 V and efficiently reduces it to 12 V while allowing for a maximum output current of 500 mA.

The compact (0.4″ × 0.5″) D24V5F15 synchronous buck voltage regulator takes an input voltage of up to 36 V and efficiently reduces it to 15 V while allowing for a maximum output current of 500 mA. Pololu 2847

The A-Star 32U4 Mini LV is a programmable module based on the ATmega32U4 from Atmel. Unlike competing products, it has an onboard switching step-up/step-down regulator that allows it to be powered efficiently from a 2.7 V to 11.8 V supply. Pololu 3103

Rechargeable NiMH Battery Pack: 4.8 V, 900 mAh, 4x1 AAA Cells, JR Connector

Tiny programmable module featuring Microchip’s PIC18F25K50 microcontroller. It packs a Micro-USB interface and 16 digital input/output pins onto a 1″×0.6″ board and ships preloaded with a USB bootloader, so no external programmer is required. Pololu 3150

A4988 Stepper Motor Driver Carrier with male header pins installed, so no soldering is required to use it with an appropriate 16-pin socket or solderless breadboard. Pololu 2980

DRV8825 Stepper Motor Driver Carrier with male header pins installed, so no soldering is required to use it with an appropriate 16-pin socket or solderless breadboard. Pololu 2982

Copper alloy traveling nut intended for use with Tr8×8(P2) threaded rods and features a mounting flange with four holes threaded for M3 screws. Pololu 2688