DC-DC Step-Down converter module. It has an input voltage from 12 to 45 V, an output voltage of 12 V and a maximum output current of up to 2.8 A. Pololu 4896

Module with 6 QTRX type optocoupler with analog output. The module operates from 2.9 V to 5.5 V, detects objects at a distance of up to 40 mm. The sensor will be used in projects that require detection of changes in the ground, e.g. in linefollower robots. Pololu 4406

DC-DC Step-Down converter module. It has an input voltage from 15 to 45 V, an output voltage of 15 V and a maximum output current of up to 2.7 A. Pololu 4897

Bipolar stepper motor. It has a resolution of 200 steps/revolution (1.8° per step), a rated voltage of 10 V, and draws a current of 0.5 A per coil. Pololu 1208

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.

The FS90 analog servo from FEETECH is a great general-purpose micro servo at a great price. Servo horns and associated hardware are included.

Key specs at 6 V: 0.10 sec/60°, 21 oz-in (1.5 kg-cm), 9.0 g.

Snap-Action Switch with 16.7mm Lever: 3-Pin, SPDT, 5A

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

Aluminum Standoff: 3/16" Length, 4-40 Thread, F-F (4-Pack)

ToF laser rangefinder. It enables detection of many objects, has a field of view of about 25 ° and is able to detect objects at a distance of up to 5 m. Communicating via the I2C interface. Pololu 3416

This programmable module combines with a Raspberry Pi to serve as the control center of a small robot or electronics project. Its Atmel ATmega32U4 microcontroller comes preloaded with an Arduino-compatible bootloader, and the board includes dual motor drivers that can deliver 1.8 A per channel to two brushed DC motors.

Motor with 20 mm diameter and 44 mm length, 156:1 metal gear, 6 V operating voltage, 0.15 A to 2.9 A power consumption, 91 RPM speed and 7.9 kg*cm maximum torque. Pololu 3456

Motor with 37 mm diameter and 54 mm length, 50:1 metal gear, 24 V operating voltage, 0,1 A to 3 A power consumption, 200 RPM speed and 23 maximum torque. Pololu 4683

Wixel Shield for Arduino

This item is a pair of motor-holding clips for the Romi chassis in white. These clips snap into the main Romi base plate, and then the motors snap into the clips. It is included as part of the white Romi Chassis Kit.

The ACS72981 current sensor module uses the Hall effect to accurately and safely measure AC and DC current, providing electrical isolation of the current path. With a wideband analog output (up to 250 kHz) and low conduction resistance (0.2 mΩ), it minimizes energy loss and offers a fast response time of less than 2 µs. Pololu 5250

Force-Sensing Resistor - 0.5" Circle

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

This power distribution board is designed specifically for the Romi chassis as a convenient way to access the chassis’s battery power and pass that on the rest of the electronics that make up your robot. Pololu 3541  

Aluminum Standoff: 1/8" Length, 4-40 Thread, F-F (4-Pack)