90 lines
5.4 KiB
Markdown
90 lines
5.4 KiB
Markdown
# DFPlayer Motherboard for Atopile
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A compact, SMD-based motherboard for the popular [DFPlayer Mini](https://www.dfrobot.com/wiki/index.php/DFPlayer_Mini_SKU:DFR0299) MP3 module, designed using the atopile hardware description language.
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This board serves as a carrier for the DFPlayer, providing stable power, protection, and convenient interfaces for input and output. It is designed to be easily integrated into larger audio projects.
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<p>
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<img src="media/pcb_layout.png" height="400" style="display:inline-block; margin-right:10px;" />
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<img src="media/3d_model.png" height="400" style="display:inline-block;" />
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</p>
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## Features
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* **Power Supply:** On-board diode is used to drop the input voltage to a DFPlayer-safe ~4.3V. Tantalum capacitors are included for power supply filtering, ensuring smooth operation.
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* **All SMD Components:** Designed for a low-profile, surface-mount assembly, making it suitable for compact enclosures.
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* **Simple Interfaces:** Utilizes standard (JST and 3.5mm Jack) connectors for power, data input, speaker output, and stereo line-level output.
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* **Compact Design:** A small footprint carrier board for the 2x8 pin DFPlayer Mini module.
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## Interfaces
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### Input
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* **Connector:** 4-pin JST PH 2.0mm
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* **Signals:**
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* `+5V`: Power input
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* `GND`: Ground
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* `TX`: Serial Transmit (connects to DFPlayer RX) protected by the 1kΩ resistor
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* `RX`: Serial Receive (connects to DFPlayer TX)
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* **Description:** This interface provides both power and UART serial communication to the DFPlayer module. It is important to note that the DFPlayer's RX pin is not 5V tolerant, so a 1kΩ series resistor is included on the board for protection.
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### Outputs
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#### 1. Speaker (Mono)
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* **Connector:** 2-pin JST PH 2.0mm
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* **Signals:**
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* `SPK+`
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* `SPK-`
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* **Description:** A direct, amplified mono output for a small speaker (up to 3W). This connects directly to the `SPK1` and `SPK2` pins of the DFPlayer.
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#### 2. Stereo Line Out
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* **Connector:** 3.5mm Stereo Audio Jack (SMD)
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* **Signals:**
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* `L`: Left Audio Channel
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* `R`: Right Audio Channel
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* `GND`: Ground
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* **Description:** A line-level stereo output suitable for headphones, external amplifiers, or other audio equipment. This connects to the `DAC_R`, `DAC_L`, and `GND` pins of the DFPlayer.
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## Power Supply Circuit
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The motherboard is designed to be powered by a standard +5V source. To ensure the DFPlayer module receives a safe operating voltage (typically 3.2V to 5.0V, with 4.2V being ideal), the following components are included:
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* **Voltage Drop Diode:** A standard silicon diode (e.g., a 1N4001 SMD equivalent) is placed in series with the power input. This provides a forward voltage drop of approximately 0.7V, effectively reducing the 5V input to a safer ~4.3V for the DFPlayer.
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* **Filtering Capacitor:** Tantalum capacitors (e.g., 100µF, 6,3V) is placed across the DFPlayer's power pins (`VCC` and `GND`). This smooths the power supply and filters out noise, which is crucial for clean audio playback.
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## Mechanical Design
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* **Mounting Holes:** The board includes four mounting holes, one in each corner.
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* **Hole Diameter:** 2,2mm, providing clearance for standard M2 screws.
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* **Compatibility:** Designed for use with M2 nylon or brass standoffs for easy mounting.
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## Bill of Materials
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| Component | Qty | Type | LCSC Part # |
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| ------------------------------------ | --- | -------------------------------------------- | -------------------------- |
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| Female 8-Pin Header | 2 | PinSocket 1x08 2.54mm Vertical | C48641756 |
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| Diode | 1 | A7 | C18199093 |
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| Capacitor | 5 | Tantalum 100uF 6.3V | C178529 |
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| UART Connector | 1 | JST PH 1x04 2.00mm Vertical | C160354 |
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| Speaker Connector | 1 | JST PH 1x02 2.00mm Vertical | C265003 |
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| Audio Jack | 1 | Jack 3,5mm Horizontal | C22459515 |
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| Resistor | 1 | 1kΩ, 0805 | C17513 |
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## Assembly
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This project is intended to be built with surface-mount components. A soldering iron with a fine tip, solder paste, and a hot air rework station are the recommended tools for a clean assembly.
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## How to Use
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1. **Prepare an SD Card:** Format a microSD card (up to 32GB) to FAT16 or FAT32. Copy your MP3 or WAV files onto the card.
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2. **Insert SD Card:** Place the microSD card into the DFPlayer module's slot.
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3. **Connect DFPlayer:** Carefully plug the DFPlayer Mini module into the female socket headers on the motherboard. Ensure the orientation is correct.
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4. **Connect Interfaces:**
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* Plug in your +5V power source and UART controller (like an Arduino or FTDI adapter) to the 4-pin JST connector.
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* Connect a speaker (e.g., 8Ω, 1W) to the 2-pin JST connector.
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* (Optional) Connect headphones or an amplifier to the 3.5mm audio jack.
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5. **Power On:** Apply power to the board and begin sending serial commands to control the DFPlayer.
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