Pathfinder

This is a USB-C powered 2-layer flight controller built around the STM32F722. It's 2S LiPo/Li-ion battery, a 6-axis IMU, a barometer, microSD logging, and two servo outputs. Lots of the sensors I used on this haven't been seen on much other flight controllers including the one I used the guide from. Feel free to use this for hobbyist and competition rocketry!

List of Materials

• MCU: STM32F722RET6
• IMU: ICM-20948 (SPI) — barometer: BME280 (I2C)
• Charger: BQ25887
• Power: TPS63070 buck-boost, LMR51430 buck
• microSD: 4-bit SD card slot
• J1/J3: servo/PWM headers
• J2: 2S battery screw terminal
• SW1 reset, SW2 boot, D1 status LED indicator
• 25MHz HSE + 32.768kHz LSE crystals
• Board: 50x55mm, 2-layer, KiCad
• the hardware folder has the KiCad files. Run lcsc.py first to get parts KiCAD didn't have. This came from the hack club guide.

I decided to implement most of these parts myself to differentiate this project with the guide I followed. This, in turn, made it a little more difficult but I'm extremely excited to get it done!

Power architecture

2S Battery ----> TPS63070 ----> VSYS ----> LMR51430 ----> 3.3V rail

USB-C VBUS ----> BQ25887 Charger

Bill of Materials

Designator(s)	Qty.	Value / Part	LCSC Part #	Purchase Link	Approx. Cost
C1, C18–C21, C26–C30, C39	11	100 nF, 0402	C1525	LCSC	$1.00
C9–C11	3	22 µF, 0805	C129302	LCSC	$2.00
C3, C4, C6, C8, C12–C14	7	10 µF, 0402	C7472949	LCSC	$3.00
C15	1	2.2 µF, 0402	C77002	LCSC	$0.50
C16, C17	2	22 µF, 0805	C129302	LCSC	$1.50
C2	1	47 µF, 0805	C76636	LCSC	$1.50
C22, C24	2	100 µF, 1210	C90143	LCSC	$3.00
C25	1	2.2 µF, 0402	C77002	LCSC	$0.50
C5, C31–C34	5	1 µF, 0402	C52923	LCSC	$1.50
C35, C36	2	6.8 pF, 0402	C6376026	LCSC	$0.50
C37, C38	2	22 pF, 0402	C1555	LCSC	$0.50
C7	1	47 µF, 0805	C76636	LCSC	$1.50
CARD1	1	DM3C-SF microSD socket	C3177034	LCSC	$3.00
D1	1	Green LED, 0402	C130723	LCSC	$0.50
J1, J3	2	PH2.54 2×3-pin headers	C42431837	LCSC	$2.00
J2	1	XY308 three-pin terminal block	C557686	LCSC	$2.00
L1	1	1 µH power inductor	C285919	LCSC	$2.00
L2	1	1.5 µH power inductor	C5289323	LCSC	$3.00
L3	1	5.6 µH inductor	C5809216	LCSC	$2.00
L4	1	FCM1608KF-601T03 ferrite bead	C141723	LCSC	$1.00
R1, R2	2	5.1 kΩ, 0402	C25905	LCSC	$1.00
R10	1	5.1 kΩ, 0402	C25905	LCSC	$0.50
R11	1	390 Ω, 0402	C25109	LCSC	$0.50
R12	1	22 Ω, 1 W balancing resistor	C3921908	LCSC	$2.00
R4–R6, R8, R13–R15, R18–R24	14	10 kΩ, 0402	C25744	LCSC	$3.00
R16	1	22 kΩ, 0402	C25768	LCSC	$0.50
R17	1	100 kΩ, 0402	C25741	LCSC	$0.50
R3	1	2.2 kΩ, 0402	C25879	LCSC	$0.50
R7	1	300 Ω, 0402	C25102	LCSC	$0.50
R9	1	30.1 kΩ precision resistor	C5842805	LCSC	$1.00
SW1, SW2	2	TS-1088-AR02016 buttons	C720477	LCSC	$2.00
U1	1	TPS63070RNMR buck-boost converter	C109322	LCSC	$5.00
U3	1	ICM-20948 motion sensor	C726001	LCSC	$18.00
U4	1	BME280 environmental sensor	C92489	LCSC	$8.00
U5	1	BQ25887RGET battery charger	C2862617	LCSC	$9.00
U6	1	LMR51430XDDCR buck converter	C5185863	LCSC	$3.00
U7	1	STM32F722RET6 microcontroller	C118207	LCSC	$18.00
USB1	1	16-pin USB Type-C connector	C2765186	LCSC	$3.00
X1	1	X322525MOB4SI crystal	C9006	LCSC	$2.00
X2	1	Q13FC1350000400 crystal	C32346	LCSC	$2.00
				Estimated component subtotal	$112.50
				Shipping, taxes and price-change buffer	$11.50
				Estimated total budget	$124.00

Prices are intentionally conservative estimates and may differ from the final LCSC cart because of stock changes, minimum-order quantities, taxes and shipping.

How To Make It Yourself

1. Run lcsc.py so the libraries resolve.
2. Open the .kicad_pro file in KiCad.
3. Export gerbers/drill/pick-and-place and send to JLCPCB for a quote.
4. Generate a BOM and assemble with a stencil, paste, and reflow.
5. Power up: 2S LIPO pack on the battery pad, J2.
6. Flash: hold SW2, reset with SW1, flash over USB1.

Note for shippers: The gerber is SimpleFlightController.zip in the production folder with the bom.csv