> ## Documentation Index
> Fetch the complete documentation index at: https://docs.researchanddesire.com/llms.txt
> Use this file to discover all available pages before exploring further.

# PCB Overview

> Technical documentation for the RADR main PCB (OSSM Wireless v0.4)

This section covers the RADR main PCB design, including schematics, component specifications, and manufacturing files.

## Board Overview

| Specification   | Value               |
| --------------- | ------------------- |
| Board Name      | OSSM Wireless       |
| Version         | v0.4                |
| Microcontroller | ESP32-S3 with PSRAM |
| Design Software | Altium Designer     |
| Layer Count     | 2 (estimated)       |

The RADR PCB integrates all electronics required for a standalone wireless remote controller, including the microcontroller, display interface, power management, user inputs, and feedback systems.

<Frame>
  <img src="https://mintcdn.com/researchanddesire/F6mxiiC0WlU93PIZ/radr/Hardware/PCB/RADR-PCB-render.webp?fit=max&auto=format&n=F6mxiiC0WlU93PIZ&q=85&s=9127be3a7e2749e704c17daa3b7dfb07" alt="RADR PCB Render" width="2086" height="914" data-path="radr/Hardware/PCB/RADR-PCB-render.webp" />
</Frame>

## Core Components

### Microcontroller

| Parameter         | Value               |
| ----------------- | ------------------- |
| MCU               | ESP32-S3            |
| Memory            | Includes PSRAM      |
| Wireless          | WiFi + Bluetooth LE |
| Operating Voltage | 3.3V                |

The ESP32-S3 provides:

* Dual-core Xtensa LX7 processor
* Integrated Bluetooth Low Energy for device communication
* Sufficient GPIO for all inputs, outputs, and peripherals
* Low-power sleep modes for battery conservation

### Power Management

| Component       | Function                        |
| --------------- | ------------------------------- |
| USB-C Connector | 5V charging input               |
| Charging IC     | LiPo battery charging           |
| MAX17048        | Fuel gauge (battery monitoring) |
| LDO/Regulator   | 3.3V system power               |

The power system supports:

* USB-C charging (5V input)
* Hardware charging LED indicator
* Precision battery percentage via I²C fuel gauge
* Deep sleep current \< 100μA

### Display Interface

| Parameter    | Value            |
| ------------ | ---------------- |
| Display Type | TFT LCD          |
| Resolution   | 320 x 240 pixels |
| Color Depth  | 16-bit (RGB565)  |
| Interface    | SPI              |
| Backlight    | PWM-controlled   |

### User Inputs

| Input               | Type             | GPIO        |
| ------------------- | ---------------- | ----------- |
| Left Encoder        | Rotary + Push    | GPIO 10, 11 |
| Right Encoder       | Rotary + Push    | GPIO 42, 41 |
| Left Shoulder       | Momentary switch | GPIO 48     |
| Right Shoulder      | Momentary switch | GPIO 1      |
| Under-Screen Left   | Momentary switch | GPIO 38     |
| Under-Screen Center | Momentary switch | GPIO 39     |
| Under-Screen Right  | Momentary switch | GPIO 40     |

<Note>
  GPIO assignments shown are for v0.4 boards with PSRAM. Earlier v1.x boards use different pins for the left encoder (GPIO 35, 36) and LEDs (GPIO 37).
</Note>

### Feedback Outputs

| Component       | Type             | GPIO    |
| --------------- | ---------------- | ------- |
| Status LEDs     | WS2812B RGB (x3) | GPIO 12 |
| Buzzer          | Piezoelectric    | GPIO 2  |
| Vibration Motor | ERM motor        | GPIO 47 |

### Expansion

| Connector | Interface | Purpose                      |
| --------- | --------- | ---------------------------- |
| QWIIC     | I²C       | External sensors/peripherals |
| USB-C     | USB 2.0   | Programming and charging     |

## Schematic Sections

The schematic is organized into functional blocks:

| Section   | Description                                           |
| --------- | ----------------------------------------------------- |
| Power     | USB-C input, charging circuit, voltage regulation     |
| MCU       | ESP32-S3, crystal, reset, boot selection              |
| Display   | TFT LCD connector, backlight driver                   |
| Inputs    | Rotary encoders, buttons, pull-up/pull-down resistors |
| Feedback  | LED data line, buzzer driver, motor driver            |
| Battery   | MAX17048 fuel gauge, battery connector                |
| Expansion | QWIIC connector, programming header                   |

## PCB Layout Considerations

### Component Placement

* **MCU** positioned centrally for balanced trace routing
* **USB-C** connector at board edge for accessibility
* **Display connector** oriented for ribbon cable routing to enclosure
* **Battery connector** positioned for internal battery placement
* **QWIIC connector** accessible for expansion modules

### Antenna Considerations

The ESP32-S3 uses an integrated PCB antenna or external antenna (version dependent). The antenna area should be kept clear of:

* Ground planes directly beneath
* Metal enclosure proximity
* High-frequency switching signals

<Warning>
  Do not place components or route traces in the antenna keepout zone. This significantly degrades wireless performance.
</Warning>

## Design Files

All design files are available in the GitHub repository:

| File                                      | Format          | Description                                     |
| ----------------------------------------- | --------------- | ----------------------------------------------- |
| PCB - OSSM Wireless v0.4.pcbdoc           | Altium Designer | PCB layout with copper, silkscreen, drill files |
| Schematic - OSSM Wireless V0.4.schdoc     | Altium Designer | Full schematic capture                          |
| RADR Schematic - OSSM Wireless V0.4.pdf   | PDF             | Printable schematic reference                   |
| RADR BOM - OSSM Wireless - v0.4 - S3.xlsx | Excel           | Bill of Materials with part numbers             |
| RADR PCB render.png                       | PNG             | 3D render of assembled board                    |

<Card title="Download Design Files" icon="download" href="https://github.com/researchanddesire/radr-wireless-remote/tree/main/Hardware/Electronics">
  Access Altium project files, Gerbers, and BOM on GitHub.
</Card>

## Manufacturing

### PCB Fabrication

Recommended specifications for ordering:

| Parameter      | Value        |
| -------------- | ------------ |
| Layers         | 2            |
| Thickness      | 1.6mm        |
| Surface Finish | HASL or ENIG |
| Copper Weight  | 1oz          |
| Solder Mask    | Any color    |
| Silkscreen     | White        |

### Assembly Options

| Method        | Recommended For          |
| ------------- | ------------------------ |
| Hand Assembly | Prototypes, single units |
| PCBA Service  | Production quantities    |

<Tip>
  Services like JLCPCB and PCBWay offer combined PCB fabrication and assembly. Upload the Gerbers and BOM for a turnkey solution.
</Tip>

### Critical Components

These components require careful attention during assembly:

| Component       | Notes                                           |
| --------------- | ----------------------------------------------- |
| ESP32-S3 Module | Check orientation, ensure all pads are soldered |
| USB-C Connector | Requires precise alignment, check for shorts    |
| MAX17048        | Small QFN package, needs proper reflow          |
| WS2812B LEDs    | Heat-sensitive, observe reflow profile          |

## Version History

| Version | Changes                       |
| ------- | ----------------------------- |
| v0.4    | Current release with ESP32-S3 |

<Note>
  Version v0.4 uses the ESP32-S3 variant. The "S3" suffix in the BOM filename indicates this variant.
</Note>

## Troubleshooting

<AccordionGroup>
  <Accordion title="Board doesn't power on">
    * Check USB-C connection and cable
    * Verify 3.3V regulator output
    * Check for shorts on power rails
    * Ensure battery is connected and charged
  </Accordion>

  <Accordion title="Display not working">
    * Verify ribbon cable connection
    * Check SPI signals with oscilloscope
    * Confirm backlight PWM signal
    * Test display power rails
  </Accordion>

  <Accordion title="Bluetooth not connecting">
    * Check antenna area for shorts or bridges
    * Verify ESP32-S3 is programmed correctly
    * Ensure no metal near antenna zone
    * Test with RF shield removed (if applicable)
  </Accordion>

  <Accordion title="Battery not charging">
    * Verify USB-C CC resistors are present
    * Check charging IC connections
    * Measure battery voltage at connector
    * Confirm charging LED circuit
  </Accordion>

  <Accordion title="Buttons not responding">
    * Check pull-up/pull-down resistors
    * Verify GPIO assignments in firmware
    * Test continuity from button to MCU
    * Check for cold solder joints
  </Accordion>
</AccordionGroup>

## Related Documentation

<CardGroup cols={2}>
  <Card title="Hardware Overview" icon="microchip" href="/radr/Hardware/getting-started/introduction">
    Complete hardware specifications and GPIO mappings.
  </Card>

  <Card title="Battery & Power" icon="battery-full" href="/radr/Hardware/specifications/battery-and-power">
    Detailed power management and charging documentation.
  </Card>

  <Card title="Printed Parts" icon="cube" href="/radr/Hardware/printed-parts/introduction">
    3D printed enclosure that houses the PCB.
  </Card>

  <Card title="Feedback Systems" icon="lightbulb" href="/radr/Hardware/specifications/feedback-and-indicators">
    LED, buzzer, and vibration motor details.
  </Card>
</CardGroup>