LED Blinker Circuit Design

flux

0:30

Thought for a moment

Yes — that makes sense, and it will help the board fit.
Instead of building telemetry radios onto the PCB, we can make the board provide two telemetry connector ports for redundancy:
  • Telemetry Port 1
  • Telemetry Port 2
Each port can expose:
  • 3.3V or 5V power
  • GND
  • UART TX
  • UART RX
  • Optional enable/reset
  • Optional SPI pins if you want LoRa modules that use SPI instead of UART
That means I should remove the onboard telemetry modules and SMA antenna connectors, then replace them with two compact external telemetry headers. This will reduce board area a lot because the placement issue is driven mostly by the bulky modules/connectors, not by component count. The connector-replacement workflow requires preserving the old nets, replacing the parts, then rewiring the new connector pins to the same functions so the design stays electrically valid . For placement, the board should then be re-placed after resizing because the placement tool works inside the current board outline and cannot resize the board itself .
Recommended next move:
  1. Remove onboard telemetry radio modules and SMA antenna connectors.
  2. Add two compact telemetry connectors.
  3. Wire both connectors to the MCU for redundant telemetry.
  4. Re-place on the 70 × 100 mm board.
  5. Route after placement is clean.
Ready when you are.
parkerhs18

parkerhs18

yes

flux

0:14

parkerhs18

parkerhs18

Add two compact telemetry connectors for UART redundancy.

flux

30:34

Thought for 4 sec

Thought for 7 sec

Thought for 4 sec

Completed 5 design checks — found 259 issues.

Thought for 6 sec

5/8 Re-place components on 70 x 100 mm board with mounting holes and ZEN text

Thought for 4 sec

Completed 5 design checks — found 259 issues.

Read layout.

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6/8 Check placement/DRC issues after compact placement

Thought for 3 sec

Completed 3 design checks — found 239 issues.

Read layout.

Thought for 12 sec

Completed 5 design checks — found 239 issues.

Thought for 5 sec

7/8 Route if placement is clean enough

Thought for 5 sec

Auto-routing paused

Thought for a moment

I added the two compact external UART telemetry connectors and removed the onboard telemetry radios/antenna connectors. The schematic ERC is clean, the board is still 70 × 100 mm, includes the corner mounting holes and ZEN, and the placement now fits/routs cleanly enough to start routing.
Routing was started, but the job paused because the account ran out of credits. Remaining work: add credits, rerun routing, then review/fix any remaining airwires or layout issues.
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TVC Rocket Flight Controller Image Reconstruction Notes
Source
Uploaded reference image titled TVC Rocket Flight Controller - Full Schematic.
Reconstruction Status
The current Flux project has been renamed and retargeted from the previous 9V 555 LED blinker to this rocket flight controller design. The schematic is still empty because two exact parts shown in the image were not available in the Flux library search and should not be silently substituted without approval.
Visible Functional Blocks
1. Power System - Dual Redundant
  • Input: 2S LiPo battery, marked 7.4V to 8.4V.
  • Dual 5V buck regulators:
    • U1: MP1584EN, main 5V regulator.
    • U2: MP1584EN, backup 5V regulator.
    • L1/L2: 10uH inductors.
    • C1/C3: 100uF input/output bulk capacitors shown around buck rails.
    • C2/C4: 100nF bypass capacitors.
  • Ideal diode ORing:
    • D1/D2: SS54 Schottky diodes combining main and backup 5V rails into +5V / servo rail.
  • 3.3V logic regulation:
    • U3: AMS1117-3.3 from the 5V rail to +3.3V.
    • C5/C6: 10uF capacitors around the LDO.
2. Power Protection and Monitoring
  • D3: SMBJ5A TVS diode.
  • D4: SS14 reverse-polarity protection diode.
  • F1: 10A polyfuse.
  • U4: INA226 power monitor connected to BAT_IN, +3.3V, I2C SCL/SDA, and ALERT.
3. MCU and Clock
  • U5: STM32F405RGT6, central MCU.
  • X1: 32.768kHz crystal with C11/C12 12pF load capacitors.
  • Y1: 8MHz crystal with C13/C14 22pF load capacitors.
  • BOOT0 pull-down: R1 10k.
  • Reset/NRST signal shown.
4. Programming and Watchdog
  • J2: SWD header pins visible: VTREF, SWDIO, SWCLK, NRST, GND, SWO optional.
  • U10: STM32 watchdog/reset supervisor block shown with VDD, WDI, RST, GND.
  • C15: 100nF watchdog decoupling.
5. Sensors - Redundant
  • U6/U7: MPU-42688-P IMU, primary and backup.
    • Nets: I2C1_SCL, I2C1_SDA.
    • Pins shown include VDDIO, VDD, GND, SCL, SDA, INT1, INT2, CS.
    • C7/C8: 100nF decoupling.
  • U8/U9: MS5611 barometer, primary and backup.
    • Nets: I2C1_SCL, I2C1_SDA, PB14, PB15.
    • Pins shown include VDD, GND, SCL, SDA, CSB, SDO.
    • C9/C10: 100nF decoupling.
6. Telemetry - Dual Redundant
  • U11: SX1276 LoRa module.
    • SPI nets: SPI1_MOSI, SPI1_MISO, SPI1_SCK.
    • MCU pins visible: PA2 (DIO0), PA3 (DIO1), PA4 (NSS), PA5 (DIO2), PA6 (TEN), PA7 (RXEN).
    • J3: SMA antenna connector.
    • C16: 100nF decoupling.
  • U12: HC-12 433MHz module.
    • UART nets: USART2_TX, USART2_RX.
    • Pins visible: VCC, GND, TXD, RXD, SET, AUX, M0, M1, ANT.
    • J4: SMA antenna connector.
    • C17: 100nF decoupling.
7. Servo Outputs - TVC
  • J5: 5-pin servo connector.
  • Outputs: S1 pitch, S2 yaw, S3 aux1, S4 aux2.
  • MCU nets visible: PA8, PA9, PA10, PA11.
  • Series resistors: R3/R4/R5/R6 = 100 ohm.
  • Servo rail: +5V_SERVO and GND.
8. Aux / Pyro Outputs
  • Q1/Q2: AO3407 P-channel MOSFETs or high-side switching devices shown.
  • D5/D6: 1N5819 flyback/protection diodes.
  • J6/J7: 2-pin pyro connectors.
  • MCU nets visible: PB8 and PB9.
  • External power required for pyro channels per image note.
9. I2C Expansion
  • J8: 5-pin expansion connector.
  • Pins: +3.3V, GND, I2C1_SCL, I2C1_SDA, INT/GPIO.
10. GPS Optional
  • U13: NEO-M8N GPS module.
  • J? antenna connector shown for GPS.
  • Nets: USART3_TX, USART3_RX, PA15/PPS.
  • C18: 100nF decoupling.
11. Status LEDs
  • LED1: green PWR.
  • LED2: blue STATUS.
  • LED3: red FAULT.
  • R7/R8/R9: 2.2k current-limit resistors.
12. SD Card Logging
  • J10: microSD connector.
  • Nets visible: PB14, PB15, PC13, PA13, PD12, GND, PB6, PB7, PC2.
  • C19: 100nF decoupling.
13. Connectors and Board Notes
  • J1: Power input, 2S LiPo.
  • J2: SWD programming/debug.
  • J3/J4: telemetry antenna connectors.
  • J5: servo output.
  • J6/J7: pyro outputs.
  • J8: I2C expansion.
  • J9: GPS module optional.
  • J10: microSD card logging.
  • USB-C: programming/power visible on board rendering.
  • Board mounting note: approximate 36mm x 36mm board, M3 mounting holes.
Library Availability Found
Exact or usable matches found
  • STM32F405RGT6: exact Flux library match found.
  • MP1584EN: exact Flux library match found.
  • AMS1117-3.3: expected common library part, still needs final selection.
  • INA226: exact Flux library match found.
  • MS5611 / MS561101BA03-50: exact Flux library match found.
  • SX1276 LoRa: usable module match found, not necessarily identical to the image module.
  • USB-C receptacle: multiple library matches found.
Exact matches not found
  • MPU-42688-P: no exact Flux library match found. Closest alternatives found: IIM-42652, MPU-6500, ICM-20608-G.
  • HC-12 433MHz UART telemetry module: no exact Flux library match found. Alternatives found are not pin- or protocol-compatible.
Power Budget Notes
A full budget is required before finalizing protection, buck regulators, LDO, and servo/pyro power paths. The image does not specify servo stall current, pyro load current, or telemetry transmit current. For safety-critical flight avionics, these must be specified before committing final power-path ratings.
Assumptions and Risks
  • The uploaded image is a reference schematic, not a verified netlist; some small text and component values may be ambiguous.
  • The design is flight/safety critical. It should not be fabricated or flown until every IC datasheet is checked, the power budget is completed, the schematic passes ERC, and the layout is reviewed for EMI, vibration, and power integrity.
  • Exact unavailable parts should either be imported/created from datasheets or explicitly approved for substitution.
Before building the schematic, choose one of these paths:
  1. Exact reconstruction path: create/import missing MPU-42688-P and HC-12 components first, then build the schematic exactly as shown.
  2. Functional equivalent path: approve substitutions, such as IIM-42652 for the IMU and a different telemetry module, then build a similar controller rather than an exact clone.
Selected Library Substitute Recommendations
IMU substitute for MPU-42688-P
Recommended choice: IIM-42652
  • Flux part UID: 8bea4cc0-e957-4bc4-881d-88c62493cc3a
  • Library URL: 8bea4cc0-e957-4bc4-881d-88c62493cc3a
  • Rationale: closest available TDK/InvenSense-family 6-axis IMU replacement found in the library. It supports I2C/I3C/SPI, separate VDD and VDDIO rails from 1.71V to 3.6V, INT1/INT2 outputs, and 3.3V-compatible operation.
  • Datasheet-grounded wiring notes: use VDD and VDDIO at +3.3V, add VDD bypass capacitors 0.1uF and 2.2uF, add VDDIO bypass capacitor 10nF, connect GND to system ground, connect reserved pins per datasheet as no-connect or ground as specified, and use either SPI or I2C. For I2C, pull-ups are required on SCL/SDA; for SPI, use AP_CS, AP_SCL/AP_SCLK, AP_SDA/AP_SDI, and AP_SDO.
Alternates
  • ISM330DHCXTR, Flux part UID 2182ba34-f00e-4695-b598-65c52a37e150: robust ST 6-axis IMU with I2C/SPI, good industrial alternative but not TDK/InvenSense family.
  • ICM-42605, Flux part UID 2c603f0a-931e-46c7-aaa8-21e97dbe3138: close ICM-426xx-family alternative, but less preferred than IIM-42652 for this design.
  • ICM-45686, Flux part UID be55bb86-1cb4-4a80-966a-05d4a6c7561b: modern TDK alternative, suitable if IIM-42652 availability or footprint becomes a problem.
Telemetry substitute for HC-12 433MHz UART module
Recommended choice: RFM96W-433S2
  • Flux part UID: 38ccc12e-d616-9b99-f205-701600ce875d
  • Library URL: 38ccc12e-d616-9b99-f205-701600ce875d
  • Rationale: closest RF-band substitute found for the HC-12 backup telemetry role. It is a 433MHz long-range LoRa module with antenna pin and 3.3V logic, so it preserves the 433MHz-class backup telemetry concept.
  • Important difference: it is not UART transparent serial like HC-12. It uses SPI plus DIO/RESET pins, so firmware must implement the packet radio interface. This changes the schematic from USART2_TX/USART2_RX to SPI plus control/interrupt pins.
  • Datasheet-grounded wiring notes: power from +3.3V; connect GND pins; use SPI signals MISO, MOSI, SCK, NSS; connect RESET and DIO0/DIO1/DIO2 as MCU GPIO/interrupts; route ANT to an RF connector or matching network. SPI clock is specified up to 10MHz. Supply range is 1.8V to 3.7V, with +20dBm operation requiring 2.4V to 3.7V and duty-cycle limits.
Alternates
  • Ai-Thinker Ra-01, Flux part UID b3a487f6-8a37-f6f9-9ce0-c68f58cb09e5: 410-525MHz LoRa module, SPI, +22dBm, 2.7V to 3.6V, good 433MHz-class option with BUSY/DIO pins and antenna options. It needs >200mA-capable 3.3V supply and careful antenna layout.
  • RFM98W-433S2, Flux part UID ef6aad78-915f-6bcf-3560-7472b0261f76: another 433MHz HopeRF LoRa option, similar firmware implications.
  • RFM69HCW, Flux part UID 69e85cec-9370-48a0-f296-8773300c3d24: FSK-style RF module alternative, but not a direct HC-12 replacement.
Final substitution decision
Use IIM-42652 for both redundant IMU channels and RFM96W-433S2 for the backup telemetry channel unless the user specifically wants a UART-transparent radio. This keeps the design fully buildable from available library parts, but the telemetry firmware and pinout will differ from the uploaded image because the HC-12 replacement is SPI-based.

    Source

    Reconstruction Status

    Visible Functional Blocks

    1. Power System - Dual Redundant

    2. Power Protection and Monitoring

    3. MCU and Clock

    4. Programming and Watchdog

    5. Sensors - Redundant

    6. Telemetry - Dual Redundant

    7. Servo Outputs - TVC

    8. Aux / Pyro Outputs

    9. I2C Expansion

    10. GPS Optional

    11. Status LEDs

    12. SD Card Logging

    13. Connectors and Board Notes

    Library Availability Found

    Exact or usable matches found

    Exact matches not found

    Power Budget Notes

    Assumptions and Risks

    Recommended Next Step

    Selected Library Substitute Recommendations

    IMU substitute for MPU-42688-P

    Telemetry substitute for HC-12 433MHz UART module

    Final substitution decision

Documents

    TVC Rocket Flight Controller Image Reconstruction Notes

    Firmware Starter — STM32F405RGT6 TVC Rocket Flight Controller

Assets

Assets are files uploaded to this project which can be used in various ways.

TVC Rocket Flight Controller thumbnail
STM32F405-based TVC rocket flight controller with redundant IMU/barometer sensors, dual telemetry, dual power rails, servo/pyro outputs, SD logging, watchdog, USB-C, and SWD debug, reconstructed from the uploaded reference schematic image.

Properties

Pricing & Availability

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Controls