The Robot Arm accessory is designed to mount to the top of the Romi chassis. Lifting an object will generally cause the Romi to tilt forward, so we highly recommend using the optional second ball caster attachment, as well as a rubber band to increase the stiffness of the built-in suspension on the front ball caster can help keep the robot stable. If you are using all 6 batteries built into the Romi chassis in series, you can use a step-down voltage regulator such as our 6V, 2.5A Step-Down Voltage Regulator D24V22F6 to safely power the servos. You can find more details about this in Section 4.
You will also need some control electronics, and you might consider some additional components like encoders, sensors, and hardware:
- Power Distribution Board for Romi Chassis – This board helps you get your Romi chassis running quickly. It solders to the chassis’s battery contacts and provides reverse battery protection, several power switching options, and convenient access to the various power busses.
 | Power Distribution Board for Romi Chassis on a black chassis. |
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 | Power Distribution Board for Romi Chassis. |
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- Motor Driver and Power Distribution Board for Romi Chassis – This board is an alternative to the Power Distribution Board mentioned above. It offers the same features (reverse battery protection, multiple power switching options, and convenient access to various power busses) along with dual motor drivers and a powerful switching step-down voltage regulator that can deliver 2.5 A at 5 V or 3.3 V.
 | Motor Driver and Power Distribution Board for Romi Chassis. |
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 | Motor Driver and Power Distribution Board for Romi Chassis. |
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- Romi 32U4 Control Board – This board turns the Romi chassis into a programmable robot based on the Arduino-compatible ATmega32U4 MCU. Its features include integrated dual motor drivers, a versatile power circuit, and inertial sensors, as well as connections for quadrature encoders and an optional LCD. The board also has the ability to interface with an added Raspberry Pi, making the foundation for a complete Raspberry Pi-controlled Romi robot.
 | Romi 32U4 Control Board on a Romi chassis, top view. |
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 | Romi 32U4 Control Board with LCD on a Romi chassis. |
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- Romi Encoder Pair Kit – Add quadrature encoders to the mini plastic gearmotors on your Romi chassis with this kit that uses a magnetic disc and Hall effect sensors to provide 12 counts per revolution of the motor shaft. These encoders can plug in directly to the Motor Driver and Power Distribution Board or the Romi 32U4 Control Board.
 | The included low-profile headers are still long enough to work with our pre-crimped jumper wires. |
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 | The Romi Encoder can plug directly into the Motor Driver and Power Distribution Board for Romi Chassis. |
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- Romi Chassis components – Chassis components are available individually for use as spare parts or for those who want to put together their own Romi chassis with the color combinations of their choosing.
 | Romi Chassis Base Plate – White. |
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 | Romi Chassis Motor Clip Pair – Blue. |
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 | Romi Chassis Ball Caster Kit – Red. |
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 | Pololu Wheel 70×8mm Pair – Yellow. |
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