Hardware Specifications¶

Microcontroller¶

Parameter	Value
MCU	ESP32-S3-WROOM-2
CPU	Dual-core Xtensa LX7, 240 MHz
Flash	32 MB (OPI 80 MHz)
PSRAM	8 MB (OPI)
WiFi	802.11 b/g/n, 2.4 GHz
USB	Native USB (CDC)

Sensors¶

Sensor	Part Number	Interface	Key Specs
IMU	IMU330	SPI (CS: GPIO 4)	6-axis accel/gyro, 416 Hz sample rate
Pitot Pressure	HSCMRRN001PDSA3	SPI (CS: GPIO 15 V4P)	Differential, 14-bit, ±1 PSI, 50 Hz read
AOA Pressure	HSCMRRN001PDSA3	SPI (CS: GPIO 6 V4P)	Differential, 14-bit, ±1 PSI, 50 Hz read
Static Pressure	HSCMRNN1.6BASA3	SPI (CS: GPIO 7)	Absolute, 14-bit, 0–23.2 PSI (1.6 bar), 50 Hz read

The IMU reads at a fixed 416 Hz; the three pressure sensors read at 50 Hz on a separate task. The SPI bus runs per-chip-select clocks — 8 MHz for the IMU, 800 kHz for the Honeywell pressure sensors (the part's datasheet maximum). | External ADC | MCP3202 | SPI (CS: GPIO 5, V4P only) | 12-bit, 2-channel (flap + volume) |

Power¶

Parameter	Value
Input Voltage	12–28V DC
Regulator	L7805ABD2T-TR (5V output)
Current Draw	TBD (low — ESP32 + sensors)

Audio¶

Parameter	Value
Interface	I2S DAC
Sample Rate	16 kHz
Bit Depth	16-bit signed
Channels	Stereo (left + right)
Output Level	Line level

Storage¶

Parameter	Value
Media	microSD card (FAT32)
Interface	SPI
Logging Rate	50 Hz default (configurable: 1, 2, 10, 25, 50, 200, or 416 Hz)
Typical File Size	~50–100 MB per hour

Pin Assignments (V4P Hardware)¶

Sensor SPI Bus¶

Pin	GPIO	Function
MOSI	17	SPI Master Out
MISO	18	SPI Master In
SCLK	16	SPI Clock
CS_IMU	4	IMU330 chip select
CS_STATIC	7	Static pressure CS
CS_AOA	6	AOA pressure CS
CS_PITOT	15	Pitot pressure CS
CS_ADC	5	MCP3202 ADC CS

SD Card SPI Bus (V4P)¶

Pin	GPIO	Function
SCLK	41	SPI Clock
MISO	42	SPI Master In
MOSI	40	SPI Master Out
CS	39	Chip Select

Audio I2S (V4P)¶

Pin	GPIO	Function
BCK	20	Bit Clock
DOUT	19	Data Out
LRCK	8	Left/Right Clock

Serial Interfaces¶

Interface	TX GPIO	RX GPIO	Baud	Notes
USB Console	—	—	921600	Native USB CDC
EFIS	— (NC)	11	115200 / 921600	RS-232 via ADM3202 (V4P RX path); rate depends on EFIS type (115200 Dynon/Garmin/MGL, 921600 VN-300)
Boom	8 (NC)	9	115200	TTL level (V4P RX)
Display	10	11 (shared)	varies	RS-232

Control Pins¶

Function	GPIO	Notes
Switch/Button	12	Internal pull-up, active low
Status LED	13	Heartbeat indicator
OAT Sensor	3 (V4P) / 14 (V4B)	DS18B20 OneWire

V4B Hardware Differences¶

Parameter	V4P	V4B
CS_AOA	GPIO 6	GPIO 15
CS_PITOT	GPIO 15	GPIO 6
SD_SCLK	GPIO 41	GPIO 42
SD_MISO	GPIO 42	GPIO 41
I2S_BCK	GPIO 20	GPIO 45
I2S_DOUT	GPIO 19	GPIO 48
I2S_LRCK	GPIO 8	GPIO 47
EFIS RX	GPIO 11 (J1 pin 25 → ADM3202 R1)	GPIO 9 (DB-15 pin 2 → J1 pin 24 → SW1, RS-232 or TTL bypass)
External ADC	MCP3202 on SPI	Direct analog (GPIO 1, 2)