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File 03 · ELRS Receiver
An ExpressLRS receiver, open from antenna to firmware.
Four board designs, one firmware. Lite runs SX1281 on 2.4 GHz with a ceramic antenna. Lite-UFL swaps to a U.FL pigtail. Mono steps up to a single LR1121 for multi-band. Gemini runs dual LR1121 in ExpressLRS Xrossband mode for frequency-diverse links.
OSHWA certified · BE000030Model· pick your build
Coming soonSKU OPENRX-LITE
Teardown
- SX1281 · 2.4 GHz LoRa radio×1
- ESP32-C3 · Wi-Fi MCU×1
- 2.4 GHz SAW band-pass filter×1
- ELRS link antenna (Molex 47948)×1
- Wi-Fi antenna (ESP32-C3)×1
- 52 MHz radio TCXO×1
- TLV75533 · 3.3 V LDO×1
- Solder pad I/O · CRSF UART×1
Published so you can study it. Produced so you don't have to.
In the box
- 1×OpenRX boardtier selected at checkout
- 1×CRSF servo cable3-pin JST-SH1.0, pre-crimped, 10 cm
- 1×Heat-shrink sleeve + double-sided tape
- 1×Build cardbatch ID, QC initials, ExpressLRS flash target, GitHub rev
Provenance
- DesignedLeuven, Belgium · schematic, PCB, BOM, firmware partnerships
- AssembledShenzhen, China · first runs, while we bring up an EU line
- NextEU assembly · in planning
Every spec, one table
- Radio
- Semtech SX1281, 2.4 GHz
- Antenna
- On-board ceramic chip, no antenna wire to tear off
- Telemetry power
- 13 dBm (~20 mW)
- Protocol
- CRSF
- MCU
- ESP32-C3, 4 MB flash
- TCXO
- 52 MHz
- Input
- 5 V pad
- Firmware
- ExpressLRS (3.5.0+)
- Flash target
- Unified_ESP32C3_2400_RX
- Flashing
- UART first, then Wi-Fi OTA / BF passthrough
- Wi-Fi antenna
- Dedicated on-board ceramic, separate from the link antenna
- Dimensions
- 10.0 × 11.5 mm
- PCB
- 6-layer, 1.0 mm
- License
- CERN-OHL-S-2.0
Files you can fork, build on, or audit.
Straight from the repo. If a link 404s, the file moved; open an issue on the matching GitHub repo and we'll point it back.
Built in the open, by whoever shows up.
Every commit on this design is public. These are the GitHub accounts behind OpenRX; the next tile is reserved.
Manufacturer
- Company
- Incutec BV
- Address
- Stapelhuisstraat 15, 3000 Leuven, Belgium
- contact@opendrone.be
