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ModalAI M0184 Gemini 915MHz ELRS

ModalAI's M0184 Gemini 915MHz ELRS

Table of contents

  1. Summary
    1. Transmitter Compatibility
    2. VOXL SDK Support
    3. Dimensions
      1. 3D Drawings
      2. 2D Drawings
    4. Features
  2. Hardware
    1. Hardware Block Diagram
    2. Connectors
      1. Summary
      2. J4 - Header Solder Pads
      3. J1 - ANT1
      4. J2 - ANT2
      5. S1 - Bind button
      6. D1 - Green LED
      7. D2 - Red LED
    3. Recommended Antennas
    4. Programming Test Points
  3. User Guides
    1. VOXL SDK
    2. VOXL 2 Wiring Guide (M0054)
  4. List of Certifications

M0184 ELRS Gemini receiver

Summary

Transmitter Compatibility

In general, follow Express LRS guidance selecting 900MHz compatible transmitters.

The M0184 runs ELRS 3.x receiver firmware bundled with voxl-elrs. A transmitter must meet all of the following to bind:

  • ELRS v3 firmware on the transmitter module. Receiver and transmitter must be on the same major ELRS version. ELRS 4.x transmitters are not supported with the M0184 and must be downgraded to the latest ELRS 3.x release using the standard ExpressLRS transmitter update process.
  • A 900 MHz or dual-band module, operating in the low band.
  • Not a 2.4 GHz-only module. 2.4 GHz-only transmitters, for example the internal ELRS module of the Radiomaster Boxer, cannot bind to the M0184.

The ELRS v3 requirement applies to the M0184. The M0220 transceiver is compatible with ELRS v4+ devices by default.

VOXL SDK Support

SDK 1.4.1 or newer required. For VOXL SDK usage, please see voxl-elrs.

Dimensions

3D Drawings

TODO

2D Drawings

TODO

Features

FeatureDetails
WeightTODO g
HxW33mm x 22mm
Frequency Bands915MHz (default), configurable to 868MHz
Input Voltage5VDC, 350mA max (TX/RX)
Serial OutputCRSF, 420k default
RF ChipDual SX1276
AntennaIPEX MHF
FirmwareELRS 3.5.3.x
MCU72MHz, 32-bit ARM M3 STM32F103C8T6
Memory20Kb RAM
 64Kbit Flash
InputsUART, push button
OutputsQTY PWM, UART, R/G LED

Hardware

Hardware Block Diagram

M0184 hardware block diagram

Connectors

Summary

BETA release: prototype hardware shown here

Hover a connector to identify it — click to jump to its details.

M0184 ELRS receiver connector callouts, both sides
ConnectorDescription
J1Antenna 1
J2Antenna 2
J4PWM, RC UART
S1Bind button
D1Green LED
D2Red LED

J4 - Header Solder Pads

PinNameNotes
1GND 
2P0PWM Channel 0, 3P3V
3P1PWM Channel 1, 3P3V
4P2PWM Channel 2, 3P3V
5P3PWM Channel 3, 3P3V
6GND 
7TXELRS TX (to VOXL2), 3P3V, 420k CRSF
8RXELRS RX (from VOXL2), 3P3V, 420k CRSF
95VInput Power, 5P0V
10GND 

J1 - ANT1

RF ANT1 path (915MHz).

J2 - ANT2

RF ANT2 path (915MHz).

M0184 with dual 915MHz dipole antennas attached

S1 - Bind button

Used to put receiver in bind mode.

To enter binding mode, press and hold the Bind button while powering on.

D1 - Green LED

Solid when bound.

D2 - Red LED

Status LED, follows ELRS standards

A constant slow blink means the receiver is not connected to a transmitter. The LED turns solid once a link is established. On a vehicle, this is the red light that keeps blinking until the transmitter is powered on and connected.

IPEX MHF + T antenna.

Programming Test Points

TODO

User Guides

VOXL SDK

For VOXL SDK usage, please see voxl-elrs.

Also see the M0184 Software User Guide.

VOXL 2 Wiring Guide (M0054)

M0184 to VOXL 2 (M0054) wiring diagram

List of Certifications

FCC US radio compliance: For evaluation only; not FCC approved for resale