Effective Build Strategy
Edit on GitHubPlan the build like a staged project so every module is tested before it is buried under the next one.
Effective Build Strategy
An Aegis-Beacon build is a sequence of small, independently testable stages. The difference between a build that works on the first try and one that needs hours of debugging is usually the order you do things in, not your soldering skill.
The one rule that saves the most time
Never cover an untested module with another module.
Every stage must end with a measurable check. If a fault is found later, you will have to undo work to reach it. If it is found at the stage boundary, the fix is a single wire or one reflow.
Stage plan
| Stage | What you build | Test gate before moving on |
|---|---|---|
| 1. Power | TP4056, cell holder, divider, ESP32 5V rail | 3.3 V on the rail; half of BAT+ on GPIO 36 |
| 2. Display | OLED on software SPI | Boot screen with a sensible battery icon |
| 3. Radio | E22 module on VSPI | Boots into BEACON, transmits, current rises during TX |
| 4. Controls | Buttons and LEDs | Each button toggles its function; LEDs light |
| 5. Audio | DAC path and jack | Tone in headphones, no clicks at silence |
| 6. GPS | NEO-6M on UART2 | Fix acquired outdoors, coordinates in the payload |
| 7. Enclosure | Case, cutouts, final fit | Everything fits without stress on cables |
Each gate is a real measurement, not a visual check. Write the measured values in the build log; they are your baseline when something drifts later.
Batch the boring work
Time is lost switching tools. Do all the repetitive operations in one sitting:
- Pre-cut and pre-tin every wire to length before starting the board.
- Solder both LEDs and their resistors in one pass.
- Crimp or pre-solder the battery holder and switch terminals together.
- Test the cell and charger on the bench before it goes anywhere near the board.
Protect your work
- Use a bench mat and wrist strap: one ESD zap can kill the ESP32 or the GPS receiver.
- Keep the antenna off the board while soldering the radio: an open SMA is fine, a whip touching the bench shorts nothing, but a disconnected 50 ohm trace acts as an antenna during TX. Fit the antenna only after the radio stage passes.
- Work cell-out until the power stage passes: a fresh 18650 can source several amps into a short.
When you are stuck
Stop and measure. The three most common stuck points and their fastest checks:
- Radio hangs on the first call: measure continuity from BUSY to GPIO 21. BUSY is the most-missed wire.
- OLED blank: check that the 7-pin display is SPI, not the 4-pin I2C variant, then verify RES and CS are high after boot.
- Battery reads 0 % or 100 % forever: the divider is disconnected. Measure the voltage directly at GPIO 36.
See Assembly Sequence for the full wiring order and Bench Checklist for the complete test list.