ELRS 2.4Ghz PWM 7CH CRSF Receiver Instruction Manual

1. Introduction

This manual provides detailed instructions for the installation, configuration, and operation of your ELRS 2.4Ghz PWM 7CH CRSF Receiver. This compact receiver is specifically designed for gliders and other fixed-wing aircraft, offering advanced features such as a built-in barometer for vertical speed telemetry and support for ExpressLRS 3.2 firmware and CRSF protocol. Its small form factor makes it ideal for installations with restricted payload bays.

2. Package Contents

Please verify that all items are present in your package:

• 1x ELRS 2.4G PWM 7CH CRSF Receiver
• 1x MHF1 Antenna
• 2.54mm straight and 90° 3×6 Dupont pins

3. Setup and Installation

3.1 Physical Overview and Pinout

Familiarize yourself with the receiver's layout and pin assignments before making any connections.

The receiver features the following pins:

3.2 Antenna Connection

Connect the provided MHF-1 antenna to the receiver's MHF-1 connector. Ensure a secure connection. The copper pipe antenna is designed for optimal 2.4GHz performance.

3.3 Initial Configuration (Wi-Fi Mode)

The receiver can be configured via Wi-Fi. Follow these steps:

1. Activate Wi-Fi:
   • If connected to a high-frequency head (transmitter module), use the transmitter's LUA script menu to activate the receiver's Wi-Fi.
   • If not connected to a high-frequency head, power on the receiver for one minute. The receiver will automatically enter Wi-Fi mode.
2. Connect to Wi-Fi: On your computer or smartphone, search for Wi-Fi networks. The hotspot name will be "ExpressLRS RX".
3. Enter Password: The connection password is "expresslrs" (all lowercase).
4. Access Configuration Page: Open a web browser and navigate to http://10.0.0.1/hardware.html.
5. Import Hardware Configuration: On the ELRS hardware configuration page, import the provided configuration file (either "PWM 7CH" or "CRSF").



6. Save Configuration: Click the button at the bottom of the page to save the configuration. The receiver will restart automatically.

3.4 Firmware Update (if necessary)

If you need to update the receiver's firmware, ensure you select the correct target in the ExpressLRS Configurator.

For this receiver, select "DIY 2400 RX PWMP EX" as the device target for firmware updates.

4. Operating Instructions

4.1 PWM/CRSF Output Switching

The receiver supports both independent PWM channel output (6CH/7CH) and CRSF output. These two output signals can be easily switched without needing to re-flash the firmware. The specific method for switching is typically done through the ExpressLRS LUA script on your transmitter or via the Wi-Fi configuration interface.

4.2 Telemetry Features

With ExpressLRS firmware and CRSF protocol, the receiver provides comprehensive telemetry data, including:

• RxBt: Receiver battery voltage.
• Curr: Current sensor data (requires external current sensor, 0~3.3V compatible).
• Capa: Capacity used.
• Bat%: Battery percentage.
• GPS: GPS related data (requires external GPS module).
• VSpd (Vario): Vertical speed telemetry provided by the built-in barometer. This feature emits ascending and descending tones, allowing you to detect lift or sink without visual reference to your transmitter.

The receiver supports up to 36V max battery voltage sensing via a built-in 1K:10K voltage divider.

4.3 Failsafe Configuration

The failsafe value is configurable. It is crucial to set up failsafe behavior in your transmitter to ensure your model reacts predictably in case of signal loss. Refer to your transmitter's manual and ExpressLRS documentation for detailed failsafe setup procedures.

5. Maintenance

To ensure the longevity and optimal performance of your receiver, follow these maintenance guidelines:

• Keep the receiver clean and free from dust and debris.
• Avoid exposing the receiver to moisture or extreme temperatures.
• Regularly inspect all connections, including the antenna, for any signs of wear or damage.
• Ensure proper ventilation around the receiver during operation.

6. Troubleshooting

If you encounter issues with your ELRS receiver, consider the following common troubleshooting steps:

• No Power/LED Off: Check power connections (5V and GND). Ensure the power source is within the rated voltage (3.5~9V).
• Binding Issues: Ensure both the receiver and transmitter module are in binding mode. Verify that the ExpressLRS firmware versions are compatible. Re-attempt the Wi-Fi configuration steps.
• No Signal/Intermittent Signal: Check antenna connection. Ensure the antenna is not obstructed and is positioned optimally. Verify that the transmitter is operating on the correct frequency and power settings.
• Incorrect Telemetry Data: Double-check sensor connections (e.g., external current sensor to ADC pin). Ensure the correct hardware configuration file has been imported.
• PWM/CRSF Output Not Working: Verify that the desired output mode (PWM or CRSF) is correctly selected via the LUA script or Wi-Fi configuration.
• Receiver Not Entering Wi-Fi Mode: Ensure the receiver is powered on for at least one minute without a high-frequency head connected, or activate it via the LUA script.

7. Specifications

8. User Tips

• For optimal telemetry performance, ensure the receiver's antenna is positioned away from carbon fiber or other conductive materials that might shield the signal.
• Always perform a range check after installation and before flight to confirm reliable signal reception.
• Regularly check for new ExpressLRS firmware updates to benefit from improved features and bug fixes.
• When configuring via Wi-Fi, ensure you are on a secure network to prevent unauthorized access to your receiver settings.

9. Warranty and Support

For any warranty claims or technical support, please contact the seller or manufacturer directly. Keep your purchase records handy as proof of purchase. Refer to the official ExpressLRS documentation and community forums for extensive resources and troubleshooting guides related to the firmware.