# SmartServo G

Source: https://checkmatedynamics.com/smartservo-g.html

[Products](https://checkmatedynamics.com/products.html) / A — Move / A2 | Brushless gimbal-motor servo

A complete brushless actuator: gimbal motor, field-oriented control, magnetic encoder and housing, on one USB-C cable. The Checkmate Leader is built from these.

**A2.1 · Board** | One board for 2804 and 5208 motors | **USD 89**

**A2.2 · G-2804 · Direct** | Direct drive, no gearbox, no backlash | **USD 159**

**A2.3 · G-2804 · 20:1** | Cycloidal, output encoder, I/O tile | **USD 249**

**A2.4 · G-5208 · Direct** | Direct drive, larger motor | **USD 249**

**A2.5 · G-5208 · 25:1** | Cycloidal, output encoder, I/O tile | **USD 399**

[Register interest](mailto:contact@checkmatedynamics.com?subject=Register%20interest%3A%20SmartServo%20G) | [Volume / OEM](mailto:contact@checkmatedynamics.com?subject=Parts%20and%20OEM%20enquiry%3A%20SmartServo%20G)

Planned prices. Not on sale yet.

*G-2804 · iFlight GBM2804H-100T* *G-5208 · iFlight GM5208, 24 winding*

**Fig. 01** SmartServo G nodes, both motor sizes Concept render

Key figures

- **Motors**: 2804 · 5208
- **Reduction**: 20:1 · 25:1
- **Encoder**: 14-bit
- **Power**: USB-C PD, 5–20 V
- **Bus**: CAN-FD
- **Torque**: Per unit Test card

Ø35 mm

Controller board, to scale | Diagram

**01** Overview

## Built for feel and fidelity, not raw force.

01

### Quiet

Field-oriented control on a gimbal motor: smooth motion with no stepping and almost no sound.

02

### Absolute

A 14-bit encoder on the motor axis with calibration stored on the node. Geared versions add an output encoder.

03

### Backdrivable

Move it by hand and record the motion. Made for leader arms, wrists, grippers, camera heads and haptics.

04

### One cable

USB-C PD power and CAN-FD between nodes on the same cable. Setup runs in the Checkmate app in your browser.

Not for lifting shoulders or wheels. For those you want a higher-torque actuator, and we’ll say so.

**02** Direct drive

## No gearbox between you and the motor.

G-2804 · Direct and G-5208 · Direct are complete nodes with the gimbal motor driving your load. Both use the same board, the same cable and the same app as the geared nodes.

01

### Backdrivable

With no gear stage to fight, the shaft can be moved by hand. That is the feel haptics, knobs and hand-held controls depend on.

02

### Smooth and quiet

Field-oriented control on a gimbal motor, with no gear stage to add backlash.

03

### Test fixtures and benches

Rate tables, load stages, camera heads and teaching benches need speed and clean torque more than reduction. The G-5208 · Direct is the larger of the two.

Planned list prices USD 159 and USD 249. Torque is measured per unit and printed on the test card. Direct-drive output covers and frames are in design.

**03** Construction

*I/O tile (optional)* *Ø35 mm controller board* *Base plate* *Gimbal motor*

**Fig. 02** The stack, 2804 version Concept render

## A round board that sits on the motor.

Controller, driver and encoder share one board on the motor’s back. The optional I/O tile stacks on top, and an aluminum cover closes it.

- STM32G431 controller, DRV8316 driver
- USB-C PD sink, capped at 20 V
- Calibration stored on the node
- Two dowels in every cap face for repeatable swaps

**04** Variants

## Two motors, direct or geared.

**A2.2–A2.3** G-2804 · Direct and G-2804 · 20:1 USD 159 / 249

Compact and light. Direct drive for handle roll, camera pan and haptic knobs. The 20:1 cycloidal for wrists, grippers and leader joints.

**A2.4–A2.5** G-5208 · Direct and G-5208 · 25:1 USD 249 / 399

Larger and stronger. Direct drive for haptics and camera heads. The 25:1 cycloidal for the heavier joints of a leader arm.

**05** Specification

|  | G-2804 · Direct | G-2804 · 20:1 | G-5208 · Direct | G-5208 · 25:1 |
|---|---|---|---|---|
| Motor | iFlight GBM2804H-100T | iFlight GM5208, 24 winding |  |  |
| Reducer | Direct | 20:1 cycloidal | Direct | 25:1 cycloidal |
| Lost motion | 0 | ~8 arcmin Estimate | 0 | ~4 arcmin Estimate |
| Encoders | Motor, 14-bit | Motor + output | Motor, 14-bit | Motor + output |
| Torque | Measured per unit and printed on the test card; curves published after the first batch |  |  |  |
| Controller / driver | STM32G431 / DRV8316 |  |  |  |
| Power | USB-C PD sink, 5–20 V |  |  |  |
| Bus | CAN-FD on the USB-C cable; classic CAN when mixed with SmartStepper |  |  |  |
| I/O | Optional tile | Tile included | Optional tile | Tile included |
| Software | Checkmate browser app over USB (Chrome, Edge) · Python SDK · LeRobot |  |  |  |

Design values. Estimates and targets are marked; each unit ships with its own measured test card.

**06** Accessories

### D3 · I/O tile

Stacks on the board. Adds Qwiic and a 4-pin AUX port for sensors, endstops and triggers.

USD 19 planned

Ring magnet and side sensor 3-axis

### B3 · Output encoder

A 3-axis magnetic sensor and ring magnet in the reducer cap. Standard on geared nodes, sold for retrofit.

USD 29 planned

### D2 · Bus cable

Full-featured USB-C carrying power, USB and CAN, with a clip that holds it in the port.

In the box

Related: [Checkmate Leader](https://checkmatedynamics.com/leader.html) · [Hub 8 Pro](https://checkmatedynamics.com/hub-8.html) · [Makers](https://checkmatedynamics.com/makers.html) · [Components](https://checkmatedynamics.com/components.html)

## The exact node inside our leader arm.

[Register interest](mailto:contact@checkmatedynamics.com?subject=Register%20interest%3A%20SmartServo%20G) | [Checkmate Leader](https://checkmatedynamics.com/leader.html)