Doppelgänger Breakout Board
Specifications & Capabilities
This product is no longer supported as of April 20, 2025. We recommend transitioning to the Doppelgänger RFID Development Board for performance and functionality improvements.
The Doppelgänger Breakout Board is intended for use only in long-range readers. It consists of the following circuitry:
| Item | Purpose | Notes |
|---|---|---|
| Reader Power | Provided via passthrough power to the reader | What comes in on VIN, goes out to the reader via VOUT |
| ESP32 Power | LDO provides stable 5VDC to the ESP32’s VUSB pin | Ensure that your ESP32 supports dual VUSB inputs (auto-switching) before powering the device with USB while the breakout board is supplying power |
| Voltage Divider | Reduces the 5V DATA0/1 signal to 3V3 for the ESP32’s GPIO pins | Not intended for card replay, do not set pins to OUTPUT |
| ESP32 | This is Feather form factor, which supports a number of boards | Recommended board is SparkFun Thing Plus C |
While the Doppelgänger Breakout Board states that the maximum input voltage is 15V, you can supply up to 28VDC ONLY IF YOU USE ACTIVE COOLING on the LDO (chip indicated by the HOT symbol). Additionally, the power input is a passthrough circuit. This means that whatever voltage you supply to the Doppelgänger Breakout Board will be passed through to your reader. Ensure that your reader is rated for the voltage that you intend to supply. Do this at your own risk!
If you need assistance connecting the Doppelgänger Breakout Board to a reader, reference the Wiring-Guide
