Do not connect a flight battery until power-off inspection passes.
Use a current-limited bench supply for first power-up.
Verify the exact purchased ESP32-S3 SuperMini pin labels against J2/J3 before inserting it.
Verify GY-87 pin labels, especially whether 3V accepts regulated 3.3V input, before soldering it permanently to J4.
1. Power-Off Inspection
Manufacturing appearance requirement: confirm the fabricated PCB uses black solder mask. White silkscreen is recommended and should remain legible for J1 pin 1/order, the GY-87 forward note, test points, and module orientation labels.
Table
Check
Method
Pass criterion
Assembly polarity
Inspect D1, D2, D3, D4, U1
All match schematic/footprint orientation
Socket mapping
Compare SuperMini silkscreen to J2/J3 mapping
Every power and used GPIO label matches; no uncertainty remains
No near-short; resistance rises as capacitors charge
Resistance 5V-to-GND
DMM resistance
No near-short
Resistance 3V3-to-GND
DMM resistance
No near-short
Ground continuity
J1 pin 1 to TP3 and module grounds
<1Ω excluding probe resistance
NC verification
J1 pin 8
Electrically open and explicitly NC
Mounting holes
Measure centers
30.5 ± fabrication tolerance in X and Y
2. Regulator-Only First Power-Up
Leave SuperMini and GY-87 removed.
Set bench supply to 6.0V and current limit to 100mA.
Connect supply ground to J1 pin 1 and positive to J1 pin 2.
Power on briefly while monitoring current and temperature.
If current limit is reached, power off immediately and locate the short/polarity error.
Table
Measurement
Point
Pass criterion
Protected input
U1 VIN / C1
Positive and below raw input only by expected protection drop
5V rail
TP1 to TP3
4.85-5.15V, stable
3V3 rail
TP2
Not present until SuperMini is installed; no unexpected voltage
Thermal check
U1, D1, F1
No rapid heating at no load
Repeat at 8.4V input. The 5V rail must remain in the same pass range.
3. SuperMini Installation and Rail Validation
Power off.
Insert the SuperMini with USB, BOOT, RESET, and antenna unobstructed.
Set current limit to 300mA for initial boot; increase only if normal radio current peaks trip it.
Power at 6.0V input.
Load the safe starter firmware through the SuperMini onboard USB.
Table
Measurement
Point
Pass criterion
5V input
TP1
4.85-5.15V
SuperMini 3V3
TP2
3.20-3.40V
Boot behavior
USB serial
Firmware banner appears; motor state reports DISARMED
Motor pins at boot
J1 pins 3-6
LOW; no startup pulse observed on oscilloscope/logic analyzer
Antenna/buttons/USB
Physical access
USB plugs in and BOOT/RESET can be operated without interference
4. GY-87 Installation and I2C Test
Before soldering, verify J4 pin order and dry-fit the GY-87 in the verified orientation.
Solder the GY-87 module/header permanently into J4 while keeping the forward/axis marking visible.
Confirm the module forward/axis marking matches the PCB note or record the required software transform.
Power on and observe the I2C scan.
Pass criteria:
SDA and SCL idle high near 3.3V.
The scan detects the populated sensor devices without bus lockup.
Effective pull-up resistance is reasonable. If the module has onboard pull-ups, do not fit another pair.
Sensor readings respond to rotation and pressure changes with no stuck values.
Fail criteria:
Either line remains low.
Bus voltage exceeds 3.3V.
No devices appear after socket/power verification.
Sensor axes cannot be reconciled with the marked orientation.
5. VBAT ADC Calibration
Keep motors and ESC disconnected.
Apply several accurate input voltages across the operating range, for example 6.0V, 7.4V, and 8.4V.
Measure each input with a calibrated DMM.
Record raw ADC millivolts and firmware-calculated VBAT.
Fit a gain/offset correction in firmware if required.
Pass criterion: after calibration, reported VBAT is within ±2% or ±0.10V, whichever is larger, across 6.0-8.4V.
Protection check: TP4 should remain comfortably below 3.3V at 8.4V input; nominal design target is about 2.30V before ADC tolerance/calibration effects.
6. ESC Current Calibration
Do not assume an amperes-per-volt scale.
First test with the ESC powered but motors stopped and record TP5/raw ADC offset.
Use an external calibrated current meter and a safely restrained motor/load, without propellers, to collect multiple current/ADC points.
Fit scale and offset from measured data and save calibration per ESC.
Pass criteria:
TP5 never exceeds the safe ADC range during tested loads.
Current reading is monotonic.
Calibrated error is within the application target established from the measured ESC behavior.
7. Motor Output Tests Without Propellers
ESC Disconnected
Probe J1 pins 3-6.
Test each channel individually with low-rate PWM first.
Verify channel identity and inactive channels remain LOW.
Pass criteria:
M1=GPIO4, M2=GPIO5, M3=GPIO6, M4=GPIO7.
Logic HIGH is approximately 3.3V and LOW is near 0V.
No channel toggles at reset or firmware upload.
ESC Connected, Motors Without Propellers
Use a current-limited source where practical.
Confirm common ground before enabling any output.
Arm only through a temporary bench-only test build with explicit local confirmation.
Spin one motor at a time at minimum command.
Pass criteria:
Correct motor responds to each command.
All motors stop immediately on disarm.
Reset, Wi-Fi loss, BLE loss, malformed command, or control-process crash produces motor-off behavior.
8. Failsafe Tests
Perform with propellers removed:
Stop sending heartbeat/commands for longer than 500ms.
Disable Wi-Fi at the controller.
Disconnect the controlling client.
Send malformed and out-of-range commands.
Press RESET during an active bench command.
Power-cycle the controller while the ESC remains powered.
Pass criterion for every case: GPIO4-GPIO7 and J1 M1-M4 return LOW, the armed state clears, and recovery does not automatically re-arm.
9. Final Schematic-to-Board Checkpoint
Before component placement/routing approval:
Confirm J2/J3 mechanical row spacing against the purchased SuperMini.
Place J1 at a board edge with side-entry cable clearance, latch access, and a visible pin-1 mark; do not infer cable order from a mating-end photograph.
Define the SuperMini body, USB plug, BOOT/RESET access, and antenna keepout envelopes.
Place J4 away from U1/L1/BUCK_SW and align its axes to the forward note.
Place J1 at a board edge with visible pin-1/order marking.
Review the four mounting-hole keepouts.
Re-run ERC/DRC after placement and before routing.
Overall Pass Criteria
The board passes bring-up only when:
5V and 3V3 rails meet limits at 6.0V and 8.4V input.
No unexpected heating or current-limit behavior occurs.
I2C sensors enumerate and axes are documented.
VBAT is calibrated to the stated accuracy.
ESC current calibration is measured, not assumed.
Each motor channel maps correctly and is low at boot/reset.
Every communication-loss and reset test forces the system disarmed.