Bluetooth LED Controller Design
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Read U1 esp32-wroom-32e_esp32-wroom-32ue_datasheet_en.pdf for pin description recommended operating co.
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Read U3 lm2596.pdf for typical application fixed output 5V indu.
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2/4 Câbler les rails, ESP32, MCP23017 et 24 sorties MOSFET
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Câbler les rails, ESP32, MCP23017 et 24 sorties MOSFET
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Project Specification: Bluetooth 24-Letter LED Controller
Project Overview
- Status: Draft / needs user confirmation before schematic recreation.
- Goal: Recreate and improve a Bluetooth-controlled PCB for driving 24 separate 12 V LED letter outputs.
- Reference provided: Uploaded schematic image titled “CARTE CONTROLEUR 24 LETTRES LED – BLUETOOTH”.
Intended Use
- Controller board for illuminated signage or decorative LED letters.
- Each output appears intended to switch one 12 V LED letter/load.
- Bluetooth control is provided by an ESP32 module.
What the Device Should Do
- Accept a 12 V DC input.
- Generate 5 V and 3.3 V logic rails.
- Use an ESP32-WROOM-32 module for Bluetooth control.
- Drive 24 low-side switched LED outputs labeled Letter 1 through Letter 24.
- Provide a mode pushbutton connected to the ESP32.
Main Features
- 24 switched 12 V LED outputs.
- ESP32 Bluetooth logic/control.
- MCP23017 I/O expander for 16 additional outputs over I2C.
- Direct ESP32 GPIO outputs for remaining LED channels.
- 12 V input protection/fusing shown in the reference.
System Architecture
Diagram
Hardware Subsystems
Power Input and Protection
- Reference shows a 12 V input connector, fuse, and diode/protection element.
- The image appears to show a 15 A fuse, but this must be confirmed.
5 V Regulator
- Reference shows LM2596S-5.0 switching regulator.
- Visible support parts include an inductor, Schottky diode, and input/output capacitors.
- Exact values are partly readable but should be verified against the regulator datasheet before implementation.
3.3 V Logic Regulator
- Reference shows AMS1117-3.3 from 5 V to 3.3 V.
- Input/output capacitors are shown; exact values should be verified against the regulator datasheet.
Controller
- Reference shows ESP32-WROOM-32.
- Bluetooth control assumed; WiFi may be available but not required unless user requests it.
I/O Expansion
- Reference shows MCP23017-E/SP I/O expander.
- Connected over I2C to the ESP32.
- Pull-up resistors on SDA/SCL are shown, likely 10 kOhm, but value confirmation is needed.
LED Output Drivers
- Reference shows 24 low-side drivers, apparently AOD408 MOSFETs or similar logic-level N-channel MOSFETs.
- Each gate has a series resistor, likely 100 ohm, and each output connects to a terminal labeled Letter 1 to Letter 24.
- Loads appear powered from +12 V and switched to ground by MOSFETs.
User Input
- One mode pushbutton shown connected to an ESP32 GPIO, with a pull-down or pull-up arrangement.
- Exact ESP32 GPIO must be confirmed from the image or selected during schematic recreation.
Interfaces and Connections
- 12 V DC power input connector.
- 24 LED letter output connectors.
- ESP32 Bluetooth interface.
- I2C bus between ESP32 and MCP23017.
- Mode pushbutton.
Power and Runtime Expectations
- Input: 12 V DC.
- Logic rails: 5 V and 3.3 V.
- Output load current: reference notes appear to say approximately 20 A total max and 3 A per output max, but this must be confirmed before selecting power-path parts and trace widths.
Power Tree and Power Budget
Table
| Rail / Path | Source | Loads | Current Assumption | Status |
|---|---|---|---|---|
| +12 V | External DC input | 24 LED letters | TBD; image suggests high current | Needs confirmation |
| +5 V | LM2596S-5.0 buck | AMS1117-3.3 input and possibly auxiliaries | TBD | Needs datasheet sizing |
| +3.3 V | AMS1117-3.3 | ESP32, MCP23017, pull-ups | TBD | Needs datasheet sizing |
Manufacturing and Assembly Expectations
- Reference mixes through-hole style components/connectors with module-style ESP32.
- User appears beginner-level; through-hole connectors and serviceable parts may be preferred unless compact assembly is required.
- High-current output routing will require careful copper width, pours, and connector ratings.
Firmware-Relevant Hardware Requirements
- ESP32 firmware should map 24 logical letter channels to GPIO/MCP23017 pins.
- I2C initialization required for MCP23017.
- Button input required for mode selection.
- Bluetooth control protocol not specified yet.
Physical Design Expectations
- Not specified yet.
- ESP32 antenna area must be kept clear if using ESP32-WROOM-32.
- High-current 12 V output connectors should be placed along board edges for wiring access.
Important Design Decisions
- Use low-side N-channel MOSFET switching for 12 V LED loads.
- Use MCP23017 to expand ESP32 GPIO count.
- Use a buck converter for 12 V to 5 V, then an LDO for 3.3 V logic.
Assumptions and Items Needing Confirmation
- Confirm that you want me to recreate this schematic in Flux from the image.
- Confirm exact power requirement: total LED current and current per output.
- Confirm whether the MOSFET part is AOD408 or a different part number.
- Confirm the output connector type/current rating and preferred pitch.
- Confirm whether the original reference should be followed exactly or improved for reliability/manufacturing.
- Confirm board size, shape, and whether the design should be hand-solderable.
- Confirm Bluetooth-only control or Bluetooth plus WiFi.
Change Notes
- Initial draft created from uploaded reference image.
- Project renamed from the random draft name to Bluetooth 24-Letter LED Controller.
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