The Happymodel 2.4GHz ELRS nano series receiver is an open source program based on ExpressLRS, we have 3 types rx module released.

The PP RX is designed by @Jye Smith from ExpressLRS development team. Its main hardware architecture is STM32L432KBU6 MCU and SX1280 RF chip. It has a built-in ceramic antenna, which is super light and small in size.

On the basis of PP RX, we have developed the Nano 2.4GHz rx of ESP8285 version named EP1 and EP2. The RF module of EP1/EP2 is the same like PP RX and use ESP8285 MCU . So you can upgrade firmware by WIFI , that’s too simple .

Due to the low-latency and high-refresh-rate RF module, they are very comfortable for FPV race and Long Range FPV. And very suitable for Tiny whoop because of the ultra light and Nano size.

PP(w/ antenna) EP1(w/o antenna) EP2(w/ antenna)
MCU STM32L432KBU6 ESP8285 ESP8285
RF Chip SX1280IMLTRT SX1280IMLTRT SX1280IMLTRT
Antenna SMD Ceramic Omnidirectional SMD Ceramic
Dimension 10mm*10mm*6mm 10mm*10mm*3mm 10mm*10mm*6mm
Weight 0.47g 0.42g 0.44g
Firmware target 6cb8152d aec8ad82 aec8ad82
Firmware upload Betaflight pass-through Wifi Wifi

EP2_RX Specifications:

Type: ISM
ESP8285 MCU
SX1280IMLTRT RF Module
SMD Ceramic antenna
Frequency Range: 2400 MHz to 2500 MHz
Maximum receive refresh rate: 500Hz
Minimum receiver refresh rate: 25Hz
Working voltage: 5v
Weight: 0.44gram
Dimension: 10mm*10mm*6mm
Peak gain: 3.7dB