1. Introduction
The Happymodel ExpressLRS ES900TX and ES900RX modules are a long-range wireless transmission system designed for remote control applications, particularly for FPV drones and RC vehicles. Based on the open-source ExpressLRS software, these modules offer ultra-long range capabilities, stable operation, and low latency. They are available in 915MHz or 868MHz frequency options.
These new ES900 series modules replace the previous ES915 series due to a shortage of SMT32 chips. The ES900TX transmitter module includes a custom heat sink and a 2006 fan that activates automatically when the TX power reaches 250mW, ensuring stable performance under high power. The modules are compatible with most OpenTX remote controllers, including Radiomaster TX16S and Jumper T12/T16/T18 series, offering a plug-and-play experience.
2. Package Contents
The ES900TX and ES900RX modules are available individually or as a combo kit. Please verify your purchase against the following lists:
ES900TX and ES900RX Combo Kit:
- 1x ES900 TX module (868MHz or 915MHz, depending on selection)
- 1x ES900 RX module (868MHz or 915MHz, depending on selection)
- 1x TX antenna (868MHz or 915MHz, depending on selection)
- 2x RX antennas (868MHz or 915MHz, depending on selection)
- 1x Molding JR Bay mounted case for TX module
- 1x Heat sink
- 1x Adapter wire
- 1x 2006 Fan
ES900TX Package (Transmitter Only):
- 1x ES900 TX module (868MHz or 915MHz, depending on selection)
- 1x TX antenna (868MHz or 915MHz, depending on selection)
- 1x Molding JR Bay mounted case for TX module
- 1x Heat sink
- 1x Adapter wire
- 1x 2006 Fan
ES900RX Package (Receiver Only):
- 1x ES900 RX module (868MHz or 915MHz, depending on selection)
- 2x RX antennas (868MHz or 915MHz, depending on selection)
3. Specifications
ES900 Series Technical Specifications:
| Feature | ES900TX | ES900RX |
|---|---|---|
| MCU | ESP32+ESP8285 | ESP8285 |
| RF Chip | SX1276IMLTRT | SX1276IMLTRT |
| Dimension | 55mm x 39mm x 11mm | 12mm x 12mm x 3mm |
| Weight | 9.2g (module only) | 0.6g (exclude antenna) |
| Antenna Connector | SMA | IPEX1 |
| VCC Input | 5V ~ 13V (Recommended 5V ~ 9V) | 5V |
| Operation Current | N/A | ~100mA |
| Rx To FC Protocol | N/A | CRSF |
| RF Frequency | 915MHz or 868MHz (EU) | 915MHz or 868MHz (EU) |
| Max Output Power | <33dBm | <17dBm |
| Firmware Upload | Wifi or Configurator | Betaflight pass-through or Wifi |
Comparison with ES915 Series (Discontinued):
| Feature | ES915 RX (Old) | ES900 RX (New) | ES915TX (Old) | ES900TX (New) |
|---|---|---|---|---|
| MCU | STM32F103RBH6 | ESP8285 | STM32F103C8T6 | ESP32+ESP8285 |
| RF Chip | SX1276IMLTRT | SX1276IMLTRT | SX1276IMLTRT | SX1276IMLTRT |
| Antenna Plug | IPEX4 | IPEX1 | SMA | SMA |
| Dimension | 16mm x 10mm x 3mm | 12mm x 12mm x 3mm | 55mm x 39mm x 13mm | 55mm x 39mm x 11mm |
| Weight | 0.7g | 0.6g | 23g (exclude antenna) | 9.2g (module only) |
| Firmware Upload | Betaflight pass-through | Betaflight pass-through or Wifi | SD-card or Configurator | Wifi or Configurator |
4. Setup
4.1 Binding Procedure (ES900RX)
- Power on the ES900RX. Wait until the red LED on the ES900RX turns off. Immediately power off.
- Repeat step 1.
- On the third power-on, the red LED light will start to double flash quickly, indicating the ES900RX is in binding mode.
- Insert the ES900TX module into your radio transmitter.
- In your radio's settings, select "External RF" mode and set it to "CRSF protocol".
- Navigate to the ELRS menu in your radio system and press "[Bind]".
- The red LED on the ES900RX module will turn off, then start blinking slowly and finally become solid, indicating successful binding.
4.2 Firmware Update
It is highly recommended to keep your ExpressLRS firmware updated for the best performance and features. Refer to the official ExpressLRS resources for the latest updates and tools:
- GitHub Source: https://github.com/ExpressLRS/ExpressLRS
- ExpressLRS Community: ExpressLRS – High Performance Radio Control Link
- Configurator Downloads: https://github.com/ExpressLRS/ExpressLRS-Configurator/releases
- Firmware Releases: https://github.com/ExpressLRS/ExpressLRS/releases
ES900RX Firmware Update by WiFi:
- Make the ES900RX enter into Bind mode (as described above).
- Wait approximately 1 minute without binding. The ES900RX would then automatically get into WiFi mode.
- Connect to the WiFi hotspot named "ExpressLRS RX" by entering the password "expresslrs".
- Open a web browser and visit "10.0.0.1".
- Choose the correct firmware file and click "update".
- Wait 1-2 minutes for the update to complete. A "firmware update successful and reboot" message will confirm completion.
ES900TX Firmware Update:
WiFi update functionality for the ES900TX is expected to be available soon. Please refer to the official ExpressLRS resources for the latest update methods.
JR Module Bay for ES900TX:
A 3D printable file for a JR module mounting bay for the ES900TX/ES915TX is available for download: Click to Download 3D Printed JR module mounting bay file.
5. Operating Instructions
Once the ES900TX module is installed in your OpenTX compatible radio (e.g., Radiomaster TX16S, Jumper T12/T16/T18 series) and the ES900RX is successfully bound to it, the system is ready for operation. Ensure your radio is configured for CRSF protocol in external RF mode. The ExpressLRS system provides a robust and low-latency link for your RC models. Refer to your radio transmitter's manual for specific external module setup instructions.
6. Maintenance
- Cooling for ES900TX: For high-power operations (above 27dBm) with the ES900TX module, it is recommended to use the included 2006 fan for forced cooling. The fan will activate automatically when the TX power reaches 250mW. Ensure the fan is free from obstructions and dust for optimal performance.
- Antenna Care: Always ensure antennas are securely connected to both the TX and RX modules before powering on to prevent damage. Avoid bending or stressing the antennas excessively.
- Firmware: Regularly check for firmware updates from the official ExpressLRS resources to benefit from performance improvements and bug fixes.
- General Cleaning: Keep the modules clean and free from dirt, dust, and moisture. Use a soft, dry cloth for cleaning.
7. Troubleshooting
- Binding Issues: If the modules fail to bind, ensure both TX and RX are on the same frequency (868MHz or 915MHz) and running compatible ExpressLRS firmware versions. Double-check the binding procedure steps carefully.
- No Link/Intermittent Link:
- Verify antenna connections on both TX and RX modules.
- Ensure the TX module is correctly seated in the radio's JR bay.
- Check the radio's external RF settings to confirm CRSF protocol is selected.
- Confirm the TX output power is appropriate for your environment and desired range.
- Check for potential local interference sources that might affect signal quality.
- Firmware Update Failure: Ensure a stable internet connection for WiFi updates. For configurator-based updates, verify that correct drivers are installed and the module is properly connected to your computer.
8. User Tips
- Keep Firmware Updated: The ExpressLRS project is actively developed. Regularly updating your firmware via the ExpressLRS Configurator will provide the latest features and performance enhancements.
- Cooling for High Power: If you plan to operate your ES900TX at higher power levels (above 250mW), the integrated 2006 fan is crucial for maintaining stability and preventing overheating. Ensure it's functioning correctly.
- Frequency Matching: Always ensure your ES900TX and ES900RX modules are matched to the correct frequency band (either 915MHz or 868MHz) for your region and for optimal performance.
9. Warranty and Support
For technical support, troubleshooting assistance, or warranty inquiries, please refer to the official Happymodel website or contact the seller directly. Additionally, the active ExpressLRS community is an excellent resource for information and peer support:
- ExpressLRS Community: ExpressLRS – High Performance Radio Control Link
- Official ExpressLRS GitHub: https://github.com/ExpressLRS/ExpressLRS
