6 layers26.9 × 26.9 mm
OpenFC
OpenDrone-hw/OpenFC-Lite-Mini
Open-source Betaflight flight controller. RP2354A, 20x20 mm, 6-layer, 3-6S, CERN-OHL-S-2.0.
131 parts147CERN-OHL-S-2.0
8 layers35 × 35 mm
OpenAIO
OpenDrone-hw/OpenAIO19Open-source AIO for 2-6S toothpick quads: flight controller, 4-in-1 AM32 ESC and ExpressLRS receiver, 25.5x25.5 mm.
- Size
- 35 × 35 mm
- Copper layers
- 8
- Thickness
- 1 mm
- Parts
- 343
- Nets
- 302
- Pads
- 1,697
- Tracks, vias
- 2,574, 2,475
- Pours
- 60
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 4 Aug 2026
- Updated
- 16 Oct 2026
Overview
OpenAIO is an open-source printed circuit board by OpenDrone-hw, from the OpenDrone-hw/OpenAIO repository on GitHub, published under the CERN-OHL-S-2.0 licence. It is an 8-layer board of 35 × 35 mm with 343 parts on 302 nets, routed with 2,574 tracks and 2,475 vias.
It is built around the AT32F421G8U7, ESP32-C3 and RP2354A, with the SX1281IMLTRT, 2450FM07D0034T and NSG2065Q among its other parts. Its parts include 115 resistors, 107 capacitors, 36 connectors, 26 transistors and 24 ICs. It belongs with the robots and motor control boards and the ESP32, RP2350 and RISC-V boards of this library.
Main components
12
AT32F421G8U7
QFN-28-EP(4x4)-40℃~+105℃ 120MHz 16KB 2.4V~3.6V 23 32 Bit 64KB ARM Cortex-M4 Built-in+External FLASH QFN-28-EP(4x4) Microcontrollers (MCU/MPU/SOC) ROHSARTERYMicrocontrollers (MCU/MPU/SOC)
ESP32-C3
QFN-32-EP(5x5)12bit 160MHz 22 3V~3.6V Others QFN-32-EP(5x5) Microcontrollers (MCU/MPU/SOC) ROHSEspressif SystemsMicrocontrollers (MCU/MPU/SOC)
RP2354A
QFN-60(7x7)150MHz 32 Bit ARM Cortex-M33 Built-in+External Power-on reset (POR)、Undervoltage detection (BOR/LVD/LVR/LVI)、Watchdog reset、Built-in general-purpose timer、Integrated LDO、Calendar function、True random number generator (TRNG)、Hardware ECC check、Independent watchdog (IWDG) QFN-60(7x7) Microcontrollers (MCU/MPU/SOC) ROHSRaspberry PiMicrocontrollers (MCU/MPU/SOC)
SX1281IMLTRT
QFN-24-EP(4x4)-132dBm -40℃~+85℃ 1.8V~3.7V 12.5dBm 2.4GHz 2.4GHz~2.5GHz 24mA 2Mbps 8.2mA LoRa SPI、UART Supports RSSI function transceiver QFN-24-EP(4x4) RF Transceiver ICs ROHSSEMTECHRF Transceiver ICs
2450FM07D0034T
SMD-4P,1x0.5mm-40℃~+85℃ 0.75dB 2.4GHz~2.5GHz 50Ω 8dB、9.5dB、25dB、30dB、30dB、35dB SMD-4P,1x0.5mm RF Filters ROHSJohanson DielectricsRF Filters
NSG2065Q
QFN-24-EP(4x4)Gate DriversWXNSIC
BMP580
LGA-10(2x2)-40℃~+85℃ 0.5pa/K 1.73V~3.6V 30Kpa~1.25bar 5.5uA 6pa 75pa I2C、SPI、I3C LGA-10(2x2) Pressure Sensors ROHSBosch SensortecPressure Sensors
COS8051SOT
SOT23-5-2.25V~2.25V -40℃~+125℃ 1 100MHz 100mA 125dB 150V/us 1pA 2.5V~5.5V 2.5pA 2.6mA 2uV/℃ 5mV 8nV/√Hz@1kHz Built-in compensation Rail-to-Rail Input, Rail-to-Rail Output SOT23-5 Operational Amplifier ROHSCOSINEOperational Amplifier
TF-021B-H265
SMD-25℃~+75℃ 2.5mm Connector and Ejector MicroSD Card (TF Card) Push-Pull SMD SD Card / Memory Card Connector ROHSSOFNGSD Card / Memory Card Connector
BMI270
LGA-14(2.5x3)-40℃~+85℃ 1.71V~3.6V 16bit 2KB 3.5uA Accelerometer Gyroscope SPI、I2C X,Y,Z X,Y,Z ±16g ±2000dps LGA-14(2.5x3) Accelerometers ROHSBosch SensortecAccelerometers
SM06B-SRSS-TB(LF)(SN)
SMD,P=1mm,卧贴-25℃~+85℃ 1 1A 1mm 1x6P 2.9mm 4.32mm 50V 6 6P 8mm Auxiliary Solder Pin Copper alloy PA SH Surface Mount, Right Angle Tin UL94V-0 White SMD,P=1mm,Surface Mount，Right Angle Wire To Board Connector ROHSJSTWire To Board Connector
TLV76733DRVR
WSON-6(2x2)-40℃~+125℃@(Tj) 1 1.4V@(1A) 16V 1A 3.3V 46dB@(1MHz) 50uA 60uVrms Fixed Over Current Protection、Over Temperature Protection、Soft Start Positive WSON-6(2x2) Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSTexas InstrumentsVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
README
README.mdOpenAIO
An all-in-one for 85 mm whoops, 2.5 inch cinewhoops and 3 inch freestyle: RP2354A flight controller, four AM32 ESC channels and an ExpressLRS 2.4 GHz receiver on one 8-layer HDI board with 25.5 x 25.5 mm mounting. Its circuits follow OpenFC-Lite-Mini, OpenESC-20x20 and OpenRX-Lite.
Why
Flight controller, ESC and receiver are usually three boards joined by connectors and wiring. On a small quad the stack costs weight and height, and the connectors are where builds fail. OpenAIO puts all three on one board and keeps the firmware stock. The market research linked under Prior art covers competing AIOs.
Specifications
From the design files. Not manufactured yet.
| Mounting | 25.5 x 25.5 mm, four 3.0 mm holes |
| Board | 35.4 x 35.4 mm, 8 layers HDI 1+6+1, 0.997 mm, 1 oz copper on all layers, ENIG |
| Input | 3S to 6S LiPo, 9.0 to 25.2 V; 2S is not supported (gate driver VCC, see research/INPUT_RANGE.md) |
| Input protection | None: no reverse polarity protection, no TVS. Fit a low-ESR electrolytic of at least 35 V on the battery leads |
| Current rating | Not established; no measurement exists |
| Flight controller | RP2354A, BMI270 IMU, BMP580 barometer, USB-C |
| OSD and blackbox | Analog PIO framebuffer OSD, microSD card |
| ESC | 4x AM32, AT32F421G8U7 + NSG2065Q + 6x DOY180N03T (30 V) per channel, one shared current sensor |
| Receiver | ExpressLRS 2.4 GHz, ESP32-C3 + SX1281, u.FL antenna |
| Outputs | +10V (always on with a battery) on SH-6 and pads, +5V and +4v5 pads, WS2812 strip pads, buzzer pads |
| Firmware | Betaflight, AM32, ExpressLRS, stock upstream |
Technical write-up, part list and layout constraints: AGENTS.md. Pinout and firmware: firmware/.
Constraints
- 25.5 x 25.5 mm mounting, the whoop and toothpick standard.
- Runs stock firmware: Betaflight on the FC, AM32 per ESC channel, ExpressLRS on the receiver. No forks.
- Parts come from the shared library first; assembly from LCSC parts, extended parts kept to a minimum.
- 8-layer HDI 1+6+1 with filled microvias; fabrication limits are in research/NEXTPCB.md.
Prior art
- OpenFC-Lite-Mini: the RP2354A flight controller
- OpenESC-20x20: the AM32 4-in-1 power stage
- OpenRX Lite: the ELRS receiver
- Market research: competing toothpick and whoop AIOs, June 2026
- Part alternatives: ESC-stage part alternatives, gate driver and FET options, March 2026
- Current sensing: shunt against copper sensing, market and literature
Notes: input range, pin constraints, board data and copper model.
Design questions
- Thermal. Four power stages next to an MCU and a radio on 25.5 mm square, with no airflow guarantee. What is the continuous current budget on 1 oz copper? The copper loss model in research/ROUTING.md is the only number so far.
- RF isolation. A 2.4 GHz receiver next to four switching power stages: ground plane and antenna placement are untested.
- Open board issues. The LED strip stage inverts, the ESC MCUs run from USB without gate drive power, and SBUS on SH-6 shares a net with the ELRS TX: firmware/ISSUES.md.
In the line
What pairs with what, and what is available: opendrone.be.
Contributing
KiCad files cannot be merged, so say what you intend to change before you do, on Discord. How everything works: CONTRIBUTING.md.
A repository holds design files only. Sourcing (suppliers, prices, quotes, RFQs, contacts) is handled by Incutec and never lives in OpenDrone repositories.
License
Hardware licensed under CERN-OHL-S-2.0, see LICENSE.
Parts
343| Qty | Value | Footprint | References |
|---|---|---|---|
| 40 | 10k | lib:R_0201_0603Metric | R2, R25, R34, R37, R38, R45, R102, R104, R105, R107, R108, R110, R111, R112, R113, R114 +24 |
| 36 | 5V | lib:small_pad | J15, J16, J17, J18, J20, J21, J23, J24, J25, J26, J27, J28, J29, J30, J31, J32 +20 |
| 24 | 100nF | lib:C_0201_0603Metric | C37, C38, C39, C43, C44, C45, C46, C50, C51, C52, C53, C57, C58, C59, C60, C104 +8 |
| 24 | 15R | lib:R_0201_0603Metric | R35, R36, R41, R42, R43, R44, R54, R55, R60, R61, R62, R63, R73, R74, R100, R101 +8 |
| 24 | DOY180N03T | lib:Diodes_PowerDI3333-8 | Q10, Q11, Q12, Q13, Q14, Q15, Q16, Q17, Q18, Q19, Q20, Q21, Q22, Q23, Q24, Q25 +8 |
| 22 | 100n | lib:C_0201_0603Metric | C1, C2, C11, C12, C13, C14, C20, C21, C26, C29, C30, C32, C34, C35, C107, C108 +6 |
| 15 | 1k | lib:R_0201_0603Metric | R5, R6, R46, R49, R52, R65, R68, R71, R84, R87, R90, R103, R106, R109, R115 |
| 14 | C | lib:C_0805_2012Metric | C90, C91, C92, C93, C94, C95, C96, C97, C98, C99, C100, C101, C102, C103 |
| 12 | 100nF | lib:C_0402_WIDE | C40, C41, C42, C47, C48, C49, C54, C55, C56, C61, C62, C63 |
| 8 | TestPoint | lib:TestPoint_Pad_D1.0mm | TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8 |
| 6 | 1uF | lib:C_0201_0603Metric | C77, C81, C83, C84, C85, C86 |
| 5 | 4.7uF | lib:C_0402_1005Metric | C3, C15, C16, C17, C25 |
| 4 | 100k | lib:R_0201_0603Metric | R1, R13, R17, R19 |
| 4 | 10R | lib:R_0201_0603Metric | R40, R59, R78, R97 |
| 4 | 220R | lib:R_0201_0603Metric | R39, R58, R77, R96 |
| 4 | 5.1k | lib:R_0201_0603Metric | R3, R4, R11, R12 |
| 4 | 75R | lib:R_0201_0603Metric | R15, R16, R26, R33 |
| 4 | AT32F421G8U7 | lib:QFN-28_L4.0-W4.0-P0.40-TL-EP2.4 | U13, U15, U17, U19 |
| 4 | LED_1_Green | lib:LED_0402_1005Metric | D4, D5, D6, D7 |
| 4 | NSG2065Q | lib:QFN-24_L4.0-W4.0-P0.50-TL-EP2.8 | U14, U16, U18, U20 |
| 3 | 10nF | lib:C_0201_0603Metric | C67, C73, C80 |
| 3 | 10uF | lib:C_0402_1005Metric | C75, C82, C88 |
| 3 | 30R | lib:R_0201_0603Metric | R8, R9, R10 |
| 3 | 510R | lib:R_0201_0603Metric | R24, R31, R32 |
| 2 | 1.2pF | lib:C_0201_0603Metric | C87, C89 |
| 2 | 15pF | lib:C_0201_0603Metric | C72, C74 |
| 2 | 2.4k | lib:R_0201_0603Metric | R14, R22 |
| 2 | 20p | lib:C_0201_0603Metric | C4, C10 |
| 2 | 22uF | lib:C_0603_1608Metric | C23, C24 |
| 2 | 22uF | lib:C_0402_1005Metric | C27, C28 |
| 2 | 4.7uF 50v | lib:C_0805_2012Metric | C18, C19 |
| 2 | 6.49k | lib:R_0201_0603Metric | R18, R23 |
| 2 | AP1606 | lib:DFN-3L_L1.0-W0.6-P0.65-BR | Q1, Q2 |
| 2 | C | lib:C_1206_3216Metric | C105, C106 |
| 2 | DSK24 | lib:SOD-123_L2.8-W1.8-LS3.7-RD | D2, D3 |
| 2 | LMR51430YFDDCR | lib:SOT-23-6_L2.9-W1.6-P0.95-LS2.9-BL | U3, U4 |
| 2 | XRTC303020D4R7MBCA | lib:IND-SMD_L3.0-W3.0_AFE303020S | L2, L3 |
| 1 | 0.2mR | lib:R_2512_6332Metric | Rsense2 |
| 1 | 1.4k | lib:R_0201_0603Metric | R29 |
| 1 | 12k | lib:R_0201_0603Metric | R28 |
| 1 | 13.7k | lib:R_0201_0603Metric | R20 |
| 1 | 15uH | lib:L_0805_2012Metric | L4 |
| 1 | 1nF | lib:C_0201_0603Metric | C69 |
| 1 | 1uF | lib:C_0402_1005Metric | C33 |
| 1 | 2.0nH | lib:L_0201_0603Metric | L6 |
| 1 | 2.5nH | lib:L_0201_0603Metric | L7 |
| 1 | 2450AT18A100E | lib:ANT-SMD_L3.2-W1.6 | AE2 |
| 1 | 2450FM07D0034T | lib:FILTER-SMD_4P-L1.0-W0.5-L | FL1 |
| 1 | 24nH | lib:L_0201_0603Metric | L5 |
| 1 | 3.9k | lib:R_0201_0603Metric | R27 |
| 1 | 470nF | lib:C_0201_0603Metric | C68 |
| 1 | 470p | lib:C_0201_0603Metric | C31 |
| 1 | 680R | lib:R_0201_0603Metric | R30 |
| 1 | 7.5k | lib:R_0201_0603Metric | R21 |
| 1 | AIO_outline | lib:AIO_outline | U24 |
| 1 | AOTA-B201610S3R3-101-T | lib:IND-SMD_L2.0-W1.6_AOTA-B201610S3R3-101-T | L1 |
| 1 | BMI270 | lib:LGA-14_L3.0-W2.5-P0.50-BR | U8 |
| 1 | BMP580 | lib:LGA-10_L2.0-W2.0-P0.50-TL_BMP580 | U26 |
| 1 | BOOT | lib:SolderPad_1.2x2.0mm | TP9 |
| 1 | CJ17-400001010B20 | lib:CRYSTAL-SMD_4P-L1.6-W1.2-BL | X2 |
| 1 | COS8051SOT | lib:SOT-23-5_L3.0-W1.7-P0.95-LS2.8-BR | U10 |
| 1 | ELRS OFF | lib:SolderJumper-2_P0.65mm_Tiny_Open | JP2 |
| 1 | ESP32-C3 | lib:QFN-32-1EP_5x5mm_P0.5mm_EP3.7x3.7mm | U22 |
| 1 | INA186A3IDCKR | lib:SOT-363_SC-70-6 | U25 |
| 1 | LED_1_Blue | lib:LED_0402_1005Metric | D1 |
| 1 | LP5912-1.8DRVR | lib:WSON-6-1EP_2x2mm_P0.65mm_EP1x1.6mm_ThermalVias | U6 |
| 1 | OW7EL89CENUNFAYLC-52M | lib:OSC-SMD_4P-L2.0-W1.6-BL_TXC_7Z | OSC1 |
| 1 | RP2354A | lib:QFN-60_L7.0-W7.0-P0.40-TL-EP3.4 | U2 |
| 1 | SDM02U30LP3-7B | lib:X3-DFN0603-2_L0.6-W0.3-RD | D8 |
| 1 | SM06B-SRSS-TB(LF)(SN) | lib:CONN-SMD_SM06B-SRSS-TB-LF-SN | U12 |
| 1 | SN74LVC1G3157DTBR | lib:X2SON-6_L1.0-W0.8-BL | U9 |
| 1 | SX1281IMLTRT | lib:QFN-24_L4.0-W4.0-P0.50-TL-EP2.6 | U21 |
| 1 | TF-021B-H265 | lib:TF-SMD_TF-021B-H265 | Card1 |
| 1 | TLV7031DPWR | lib:X2SON-4_L0.8-W0.8-P0.48-TL-A | U11 |
| 1 | TLV76733DRVR | lib:WSON-6-1EP_2x2mm_P0.65mm_EP1x1.6mm | U7 |
| 1 | TS2306A 240GF MSM 9_C2976675 | lib:SW-SMD_4P-L3.0-W2.0-P0.85-LS3.5 | U1 |
| 1 | TYPE-C 16P QTWT | lib:USB-TYPE-C-SMD_TYPE-C-16P-QTWT | USB1 |
| 1 | U.FL-R-SMT-1(80) | lib:RF-SMD_FRF05002-JSS103M | JP1 |
| 1 | XL-1010RGBC-WS2812B | lib:LED-SMD_4P-L1.0-W1.0-TL_XL-1010RGBC-WS2812B | D9 |
| 1 | XTM25012000JT00351001 | lib:CRYSTAL-SMD_4P-L2.5-W2.0-BL-A | X1 |
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Questions
How big is the OpenAIO PCB?
It measures 35 × 35 mm and has 8 copper layers, 1 mm thick.
What parts does the OpenAIO use?
343 parts, built around the AT32F421G8U7, ESP32-C3, RP2354A and SX1281IMLTRT. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the OpenAIO KiCad files?
From the OpenDrone-hw/OpenAIO repository on GitHub, at the commit this page was made from: the board is hardware/OpenAIO.kicad_pcb and its schematic hardware/OpenAIO.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the OpenAIO design in my own project?
Its repository publishes it under the CERN-OHL-S-2.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).