Wiring and Connectors
Edit on GitHubWire gauge, connectors and routing for the whole build: power, SPI, audio and buttons
Wiring and Connectors
Overview
Good wiring is the difference between a beacon that works for years and one that fails on a cold mountain. This page covers wire choices, connector types and routing rules for the Aegis-Beacon.
Wire Gauge by Function
| Circuit | Gauge | Why |
|---|---|---|
| Battery + TP4056 | 20-22 AWG | Carries up to 1 A charge current |
| 3.3 V rail | 24-26 AWG | A few hundred mA |
| SPI / buttons / OLED | 26-30 AWG | Signal only |
| Audio | 26 AWG shielded | Prevents buzz pickup |
| Antenna feed | Coaxial | Keep short; do not substitute stranded wire |
Connector Types
| Connector | Use | Notes |
|---|---|---|
| DuPont headers | Bench prototypes | Fine for breadboard, poor for field |
| JST-XH | Battery and modules | Locking, common on hobby cells |
| Pin headers + screw terminals | Power | Easy rework |
| SMA | Antenna | Use the E22’s onboard SMA |
| 3.5 mm TRRS jack | Audio | Panel-mount with nut |
Tip
For a field unit, solder everything directly and use a JST connector only at the battery. Every extra connector is a possible cold joint or corrosion point.
Routing Rules
- Keep the antenna feed away from the battery and the audio path.
- Run power and signal wires on opposite sides where possible.
- Twist the GPS UART pair (RX/TX) together to reject noise.
- Keep SPI leads under ~10 cm to avoid bus timing issues.
- Add a drop of hot glue or cable tie at every strain point.
Audio Shielding
The DAC output is low level. If the audio wire runs past the radio, shield it:
- Use a two-core shielded cable.
- Connect the shield at the jack ground end only.
- Keep the 100 ohm series resistor and 10 uF cap near the ESP32.