This small synchronous switching step-down (or buck) regulator takes an input voltage of up to 38 V and efficiently reduces it to 9 V. The board measures only 0.7″ × 0.7″, but it allows a typical continuous output current of up to 2.5 A. Typical efficiencies of 85% to 95% make this regulator well suited for powering moderate loads like sensors or small motors.

These 17 mm long aluminum adapters convert a 3 mm diameter shaft to a 12 mm hex shaft that compatible with many common hobby RC wheels. The set includes two adapters, two M4 screws for securing wheels to the adapters, four M3 set screws for securing the adapters to motor shafts, and one 1.5 mm Allen wrench for use with the set screws.

A set of two Pololu wheels measuring 40x7mm in red. Fits D-shaped shaft with a diameter of 3mm. Pololu 1453

A-Star 32U4 Prime SV - a programmable Arduino board, based on the Atmel ATmega32U4 microcontroller from the AVR family. Version with soldered connectors, without micro-SD card slot, without display. Polol 3113

The Pololu A-Star 32U4 Prime is a general-purpose programmable board based on Atmel’s ATmega32U4 AVR microcontroller and arranged in the common Arduino form factor exemplified by the Uno R3 and Leonardo. Pololu 3114

The A-Star 32U4 Prime SV is a programmable board based on Atmel’s ATmega32U4 microcontroller and arranged in the common Arduino form factor. The A-Star Prime offers many additional features and improvements over competing products. Pololu 3115

Hybrid bipolar stepper motor eith integrated 18cm (7″) threaded rod as its output shaft, turning it into a linear actuator capable of precision open-loop positioning. The motor has a 1.8° step angle (200 steps/revolution) and each phase draws 1.7A at 2.8V, allowing for a holding torque of 3.7kg-cm (51 oz-in). Pololu 2689

Pololu 5V Step-Up/Step-Down Voltage Regulator S18V20F5

The Step-Down D24V6F9 Buck Voltage Regulator module gives the output voltage of 9V with a wide input voltage range of 11.5-42V and a maximum output current of 600 mA. Pololu 2108

10:1 Micro Metal Gearmotor MP

Bipolar stepper motor. It has a resolution of 200 steps/revolution (1.8° per step), a rated voltage of 2.5 V, and draws a current of 2.8 A per coil. Pololu 1474

Bipolar stepper motor. It has a resolution of 200 steps/revolution (1.8° per step), a nominal voltage of 6.3 V, and draws a current of 0.3 A per coil. Pololu 2294

Bipolar stepper motor. It has a resolution of 200 steps/revolution (1.8° per step) with a double shaft, a rated voltage of 6.3V, and draws a current of 0.3A per coil. Pololu 2294

Bipolar stepper motor. It has a resolution of 200 steps/revolution (1.8° per step), a rated voltage of 5.4 V, and has a current consumption of 1 A per coil. Pololu 2296

Tamiya 72007 4-Speed High-Power Gearbox Kit

75:1 Micro Metal Gearmotor HP with Extended Motor Shaft

75:1 Micro Metal Gearmotor MP

Unipolar/bipolar stepper motor. It has a resolution of 200 steps/revolution (1.8° per step), a rated voltage of 3.2 V, and draws a current of 2.8 A per coil. Pololu 1478

Unipolar/bipolar stepper motor. It has a resolution of 200 steps/revolution (1.8° per step), has a nominal voltage of 8.6 V, and draws a current of 1 A per coil. Pololu 1477