Using an ESP based receiver - ExpressLRS/Backpack GitHub Wiki

BOM:

• Silicon wire
• Heat shrink
• ESP based ExpressLRS receiver (this example uses the Happy Model EP1)

Assembly

1. Solder 4 silicon wires to the GND, 5V, TX and RX pads on the receiver

2. Add a small amount of solder to the BOOT pin on the receiver, then carefully add the 5th silicon wire. Take care that you don't bridge the BOOT pad to the GND pad next to it.

3. Remove the rapidfire from the goggles, and split the 2 PCBs in half (remove the plastic standoff first)

4. Solder the other end of the 5 wires to the rapidfire header using the pinout below: Where:

• The BOOT pad on the receiver is CLK
• The RX pad on the receiver is DATA
• The TX pad on the receiver is CS

5. Apply heat shrink to the receiver

6. Install the Rapidfire back into the module, and tuck the VRX-Backpack into the space above the Rapidfire:

7. Before attempting to flash the firmware onto the receiver to transform it into a VRX-Backpack, power up the goggles, and use the channel button furthest away from the faceplate to set the channel as high as it will go (channel 8). Power cycle the goggles / module, and flash the receiver.