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Below is the updated schematic plan that incorporates all the necessary parts. You can click “Apply changes” in Flux to update your project with these components and wiring instructions:
Updated Schematic Plan
-
ESP32 Module & I²C Expanders:
- ESP32 Module:
- U1: Use your existing ESP32-WROOM-32D.
- Verify that its power pins are connected to the 5V rail and its ground is tied to the common ground.
- MCP23017 Expanders:
- Add four additional SMD MCP23017-E/SP chips, so you have a total of five.
- Set their address pins (A0, A1, A2) to assign unique I²C addresses (e.g., 0x20–0x24).
- Place a 0.1 µF decoupling capacitor between VDD and GND for each expander.
- ESP32 Module:
-
USB Programming & microSD Interfaces:
- USB Interface:
- Include an SMD USB-to-UART bridge (such as CP2102 or CH340) with its necessary support circuitry.
- Route its TX/RX lines to the ESP32’s RX/TX pins.
- Connect the DTR/RTS lines of the bridge to the ESP32’s EN (reset) and IO0 (boot) pins so that auto-program mode is supported.
- Add a mini-USB or micro-USB connector on the PCB labeled “USB PROG”.
- MicroSD Interface:
- Confirm that the existing J2 (TF-015) microSD card connector is wired correctly to the ESP32’s SPI interface (MOSI, MISO, SCLK, and a dedicated chip select pin), with proper pull-ups and bypass capacitors as needed.
- USB Interface:
-
Power Input, Voltage Conversion, and Protection:
- 12V Input & Protection:
- Add a dedicated connector labeled “12V IN” to receive power from your benchtop 12V supply.
- Immediately after the 12V IN, include a high-quality resettable PTC fuse and a TVS diode (with an appropriate clamping voltage) to protect against over-current and voltage surges.
- Branch the 12V rail to a connector labeled “12V OUT” for fans or other 12V peripherals.
- Buck Converters:
- Add a quality buck converter to step 12V down to 5V. Route the 5V output to a dedicated connector labeled “5V OUT”.
- Add a second buck converter to step 12V down to 3.3V, with its output connected to a dedicated connector labeled “3.3V OUT”.
- 12V Input & Protection:
-
Sensor Board Interface:
- Headers for Sensors:
- Add SMD headers or quick-connect connectors to interface with 72 microswitch inputs.
- Route these sensor signals to the appropriate inputs on the MCP23017 expanders.
- Headers for Sensors:
-
User Interface: Remote Start & Toggle Switch:
- Remote Start:
- Add a dedicated header for a remote pushbutton. This header will allow you to connect an external, vibration-resistant start switch to a designated ESP32 GPIO.
- Toggle Switch:
- Integrate an SMD on/off toggle switch into the power circuitry (ideally on the 5V rail) so that the circuit can be safely turned off.
- Remote Start:
-
Thermal Management & Fan Control:
- Fan Connector:
- Add a connector labeled “FAN 12V OUT” that provides 12V to a cooling fan.
- Include a MOSFET switching circuit (with a flyback diode across the fan) controlled by the ESP32 (using one of its GPIOs) for automated fan control.
- Optional Temperature Sensor:
- Optionally, add an SMD temperature sensor (such as an SMD LM35 or a digital sensor) near the regulators to monitor temperature for dynamic fan control.
- Fan Connector:
Next Steps
-
Apply Changes:
Use the “Apply changes” function in Flux to update your project with these schematic modifications. -
Wire the Schematic:
Connect all the components following the wiring plan above. Ensure that each net is clearly labeled (power rails, I²C bus, SPI for microSD, sensor lines, LED data outputs, etc.) and that proper decoupling is in place. -
Run DRC:
Once wiring is complete, run the Design Rule Check in the REVIEW tab to verify that the schematic meets all design standards. Resolve any flagged issues. -
Proceed to PCB Layout:
After the schematic is complete and error-free, transition to the PCB layout stage where you place the footprints and route the board.
This updated plan adds all the required parts and their interconnections. Let me know if you need step-by-step guidance on wiring specific sections or any further assistance before finalizing your schematic.
Apply changes and wire the schematic
314 days
Ready.
F1
U11
U2
U3
SW1
J2
C1
Capacitance
0.1uF
Q1
C2
Capacitance
0.1uF
LED1
U6
C3
Capacitance
0.1uF
U5
J1
C4
Capacitance
0.1uF
U4
Reviews
Electrical Rule Checks
Duplicate Designators
Reports components with identical designators.
No-Connect Violation
Reports no-connect pins that are connected.
Missing Power
Reports power input pins that are not connected to a power source.
Single Pin Nets
Reports nets that have only one pin connected.
Missing Designator • 1
Component | |
|---|---|
Design Rule Checks
Overlapping Copper
Reports copper elements that are shorting.
Invalid Layer
Reports nodes that are assigned to a layer that doesn't exist in the layout stackup.
Component Overrides
Reports components that have been modified using the "!important" flag.
Airwires
Reports missing routed traces between pads in a net.
Layers with Multiple Fills
Reports layers that have multiple copper fills of different nets. Make sure the Connected Layers rule value of nets with fills is valid.
Floating Copper
Detect any via, trace or copper fill island that is not connected to any net.
Protected Intrusions
Reports intrusions from objects of other nets into polygons or fills that have the Protected layout rule applied.
Missing Footprints
Reports components that need a footprint but don't have one.
System Checks
Auto-Layout
BetaReports issues with Auto-Layout if Flux cannot route something or must ignore a configuration.
- Wirelessly connects nets on schematic. Used to organize schematics and separate functional blocks. To wirelessly connect net portals, give them same designator. #portaljharwinbarrozo43.0M
- Wirelessly connects power nets on schematic. Identical to the net portal, but with a power symbol. Used to organize schematics and separate functional blocks. To wirelessly connect power net portals, give them the same designator. #portal #powerjharwinbarrozo11.4M
- A generic fixed resistor for rapid developing circuit topology. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard resistor values: 1.0Ω 10Ω 100Ω 1.0kΩ 10kΩ 100kΩ 1.0MΩ 1.1Ω 11Ω 110Ω 1.1kΩ 11kΩ 110kΩ 1.1MΩ 1.2Ω 12Ω 120Ω 1.2kΩ 12kΩ 120kΩ 1.2MΩ 1.3Ω 13Ω 130Ω 1.3kΩ 13kΩ 130kΩ 1.3MΩ 1.5Ω 15Ω 150Ω 1.5kΩ 15kΩ 150kΩ 1.5MΩ 1.6Ω 16Ω 160Ω 1.6kΩ 16kΩ 160kΩ 1.6MΩ 1.8Ω 18Ω 180Ω 1.8KΩ 18kΩ 180kΩ 1.8MΩ 2.0Ω 20Ω 200Ω 2.0kΩ 20kΩ 200kΩ 2.0MΩ 2.2Ω 22Ω 220Ω 2.2kΩ 22kΩ 220kΩ 2.2MΩ 2.4Ω 24Ω 240Ω 2.4kΩ 24kΩ 240kΩ 2.4MΩ 2.7Ω 27Ω 270Ω 2.7kΩ 27kΩ 270kΩ 2.7MΩ 3.0Ω 30Ω 300Ω 3.0KΩ 30KΩ 300KΩ 3.0MΩ 3.3Ω 33Ω 330Ω 3.3kΩ 33kΩ 330kΩ 3.3MΩ 3.6Ω 36Ω 360Ω 3.6kΩ 36kΩ 360kΩ 3.6MΩ 3.9Ω 39Ω 390Ω 3.9kΩ 39kΩ 390kΩ 3.9MΩ 4.3Ω 43Ω 430Ω 4.3kΩ 43KΩ 430KΩ 4.3MΩ 4.7Ω 47Ω 470Ω 4.7kΩ 47kΩ 470kΩ 4.7MΩ 5.1Ω 51Ω 510Ω 5.1kΩ 51kΩ 510kΩ 5.1MΩ 5.6Ω 56Ω 560Ω 5.6kΩ 56kΩ 560kΩ 5.6MΩ 6.2Ω 62Ω 620Ω 6.2kΩ 62KΩ 620KΩ 6.2MΩ 6.8Ω 68Ω 680Ω 6.8kΩ 68kΩ 680kΩ 6.8MΩ 7.5Ω 75Ω 750Ω 7.5kΩ 75kΩ 750kΩ 7.5MΩ 8.2Ω 82Ω 820Ω 8.2kΩ 82kΩ 820kΩ 8.2MΩ 9.1Ω 91Ω 910Ω 9.1kΩ 91kΩ 910kΩ 9.1MΩ #generics #CommonPartsLibraryjharwinbarrozo1.5M
- A generic fixed capacitor ideal for rapid circuit topology development. You can choose between polarized and non-polarized types, its symbol and the footprint will automatically adapt based on your selection. Supported options include standard SMD sizes for ceramic capacitors (e.g., 0402, 0603, 0805), SMD sizes for aluminum electrolytic capacitors, and through-hole footprints for polarized capacitors. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard capacitor values: 1.0pF 10pF 100pF 1000pF 0.01uF 0.1uF 1.0uF 10uF 100uF 1000uF 10,000uF 1.1pF 11pF 110pF 1100pF 1.2pF 12pF 120pF 1200pF 1.3pF 13pF 130pF 1300pF 1.5pF 15pF 150pF 1500pF 0.015uF 0.15uF 1.5uF 15uF 150uF 1500uF 1.6pF 16pF 160pF 1600pF 1.8pF 18pF 180pF 1800pF 2.0pF 20pF 200pF 2000pF 2.2pF 22pF 20pF 2200pF 0.022uF 0.22uF 2.2uF 22uF 220uF 2200uF 2.4pF 24pF 240pF 2400pF 2.7pF 27pF 270pF 2700pF 3.0pF 30pF 300pF 3000pF 3.3pF 33pF 330pF 3300pF 0.033uF 0.33uF 3.3uF 33uF 330uF 3300uF 3.6pF 36pF 360pF 3600pF 3.9pF 39pF 390pF 3900pF 4.3pF 43pF 430pF 4300pF 4.7pF 47pF 470pF 4700pF 0.047uF 0.47uF 4.7uF 47uF 470uF 4700uF 5.1pF 51pF 510pF 5100pF 5.6pF 56pF 560pF 5600pF 6.2pF 62pF 620pF 6200pF 6.8pF 68pF 680pF 6800pF 0.068uF 0.68uF 6.8uF 68uF 680uF 6800uF 7.5pF 75pF 750pF 7500pF 8.2pF 82pF 820pF 8200pF 9.1pF 91pF 910pF 9100pF #generics #CommonPartsLibraryjharwinbarrozo1.5M
- A generic fixed inductor for rapid developing circuit topology. *You can now change the footprint and 3D model at the top level anytime you want. This is the power of #genericsjharwinbarrozo15.2k
- An electrical connector acting as reusable interface to a conductor and creating a point where external circuits can be connected.Terminal
- 47 kOhms ±5% 0.125W, 1/8W Chip Resistor 0805 (2012 Metric) Automotive AEC-Q200 Thick Film #forLedBlinkjharwinbarrozo1.2M
- 10uF Capacitor Aluminum Polymer 20% 16V SMD 5x5.3mm #forLedBlink #commonpartslibrary #capacitor #aluminumpolymer #radialcanjharwinbarrozo1.2M
- Yellow 595nm LED Indication - Discrete 1.7V 1206 (3216 Metric) #forLedBlinkjharwinbarrozo1.1M
Inspect
HRG 1
Controls
Properties
Availability & Pricing
| Distributor | Qty 1 | |
|---|---|---|
| Arrow | $270.76–$274.12 | |
| Digi-Key | $305.25–$305.94 | |
| LCSC | $318.89–$319.40 | |
| Mouser | $309.51 | |
| Verical | $274.07–$279.43 | |
Assets
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