This section instructs on how enrich your Stratux (OGN) Flarm with a barometric pressure altitude sensor, when using a TTGO T-Beam (ESP32) to send you aircraft's position to others.
This is needed to send your barometric pressure altitude rather than GPS altitude to other aircrafts and solves the problem explained here
- Barometric pressure altitude sensor (BMP280) to be soldered to pins "3V3", "GND", "22", "21".
using BMP280 on T-Beam (Pin 3V3, GND, 22, 21) 
how to add pressure sensor to TTGO T-Beam (ESP32)
| VCC to 3V3 power |
| GND to GND |
| SCL to 22 |
| SDA to 21 |
Original Source: https://github.com/b3nn0/stratux/wiki/Pressure-Sensor-(BMP280)