1. Einleitung
The Speedybee RadioMaster ER4 2.4GHz ELRS PWM Receiver is designed for remote control applications, offering high performance and reliability. This receiver is based on the ExpressLRS system, known for its flexible configuration, fast response speed, and ultra-long range capabilities. Its compact and lightweight design makes it suitable for various models, including small aircraft, ship models, and car models.
This manual provides essential information for the proper installation, operation, and maintenance of your ER4 receiver.
2. Produktüberschreitungview
The ER4 receiver features 4 PWM channels, allowing it to drive up to four servos simultaneously. It incorporates advanced features such as automatic voltage telemetry for both external battery voltage and built-in receiver voltage. The receiver also supports Wi-Fi updates and WEBUI configuration for easy firmware management and settings adjustments.

Figure 2.1: Speedybee RadioMaster ER4 ELRS PWM Receiver with antenna and servo pins.

Figure 2.2: Dimensions of the ER4 ELRS PWM Receiver, showing its compact size (30mm length, 15mm width, 5mm height).

Abbildung 2.3: Überview of ExpressLRS system features, highlighting high performance, reliability, fast response, flexible configuration, ultra-long range, 2.4 GHz frequency, up to 100mW telemetry power, up to 8 output channels (for ER8), and battery telemetry.

Abbildung 2.4: Ausführlich view of the optimized PCB design, featuring a high-quality 2.54mm connector with 2µm gold plating for strong corrosion resistance.
3. Einrichtung
3.1 Komponenten
The ER4 receiver package includes:
- ER4 ELRS-PWM-Empfänger
- 15 cm high sensitivity antenna
- Heat-shrink tubes
- Bandtage Telemetriedraht
3.2 Verdrahtung und Anschluss
Connect the receiver to your model's flight controller or servos using the provided 2.54 mm connectors. The ER4 supports 4 PWM channels. If more than one servo is connected to a single channel, a Y-cable may be required.

Figure 3.1: The ER4 receiver connected to servos, illustrating its 4 PWM channel support. Note that using multiple servos on one channel may require a Y-cable.
3.3 Bindung
The ER4 receiver utilizes the ExpressLRS system for binding. Refer to your ExpressLRS transmitter module's instructions for the specific binding procedure. Typically, this involves putting both the transmitter and receiver into binding mode. The ER4 supports bind phrases for simplified setup.
4. Betrieb
4.1 Servo Control
Once bound, the ER4 receiver will output PWM signals to the connected servos based on the commands from your ExpressLRS transmitter. Ensure that the servo connections correspond to the desired control channels on your transmitter.
4.2 Voltage Telemetrie
The ER4 receiver supports automatic voltage telemetry. This allows you to monitor either the external battery voltage (if connected via the dedicated telemetry wire) or the built-in receiver voltage directly from your compatible ExpressLRS transmitter. Connect the included voltage telemetry wire to the appropriate port on the receiver and the battery for external voltage Überwachung.
5. Wartung
5.1 Firmware-Updates
The ER4 receiver supports Wi-Fi updates. This allows for convenient firmware upgrades to ensure optimal performance and access to new features. Connect the receiver to a power source, then access its Wi-Fi hotspot from a computer or mobile device to perform updates via a web Schnittstelle (WEBUI configuration).
5.2 Allgemeine Pflege
Keep the receiver clean and free from dust and moisture. Avoid exposing it to extreme temperatures or physical shock. Ensure the antenna is securely connected and positioned for optimal signal reception.
6. Fehlerbehebung
Sollten Sie Probleme mit Ihrem ER4-Empfänger haben, beachten Sie Folgendes:
- Keine Signal-/Bindungsprobleme: Ensure both the transmitter and receiver are powered on and in binding mode. Verify that the bind phrase is correctly set on your transmitter. Check for proper antenna connection.
- Intermittierende Verbindung: Check antenna placement and ensure it is not obstructed by carbon fiber or metal components. Verify the range and power settings on your transmitter.
- Falsche Servobewegung: Confirm that servos are connected to the correct PWM channels. Calibrate your transmitter and check channel assignments.
- Telemetry Data Missing: Stellen Sie sicher, dass die Lautstärketage telemetry wire is correctly connected to both the receiver and the battery (if using external voltage monitoring). Verify telemetry settings on your transmitter.
- Firmware-Update fehlgeschlagen: Ensure a stable Wi-Fi connection during updates. Re-attempt the update process.
For further assistance, refer to the official ExpressLRS documentation or contact Speedybee customer support.
7. Spezifikationen
| Besonderheit | Spezifikation |
|---|---|
| Modellname | ER4 2.4-GHz-ELRS-PWM-Empfänger |
| Marke | SPEEDY BEE |
| Kabelloser Typ | Radiofrequenz |
| Konnektivitätstechnologie | W-lan |
| Prozessor | ARMv7 |
| RAM | LPDDR4 |
| Betriebssystem | FreeRTOS |
| Artikelgewicht | 0.317 Unzen |
| Produktabmessungen (L x B x H) | 1.46 x 0.75 x 0.51 Zoll |
| Im Lieferumfang enthaltene Komponenten | ELRS Receiver, Antenna, Telemetry Wire, Heat-shrink tubes |
8. Offizielles Produktvideo
Video 8.1: Ein offizielles Produktvideoasing the RadioMaster ER Series ELRS PWM Receivers, including the ER4 model. This video provides a visual overview of the receiver's features and design.
9. Garantie und Support
For warranty information and technical support, please refer to the official Speedybee webBesuchen Sie unsere Website oder kontaktieren Sie Ihren Händler. Bewahren Sie Ihren Kaufbeleg für eventuelle Garantieansprüche auf.





