Portable DIY Electronics Workstation

This is a portable multi-purpose device designed for various electronics applications. It combines versatility, portability, and functionality, making it ideal for both beginners and professionals. With its compact design and multiple features, it serves as a reliable tool for different projects and experiments.

Raspberry pi 4B (DFrobot)

7" HDMI Display with Capacitive Touch (DFrobot)

DC-DC Buck Converter (DFrobot)

Raspberry Pi 4B GPIO Terminal Block HAT(DFrobot)

Spacer kit (DFrobot)

PCB (NEXTPCB.COM)

18650 Battery Holder -3Nos

3S 18650 10A BMS

5mm Led

9v Buzzer

1k Resistor

ON/OFF Switch -3 Nos

XL4015 Module

USB Socket-2 Nos

DC Volt Amp Meter

18650 Battery Indicator Module

Acrylic (laser cut)

12V Socket

USB A to Type C Cable

HDMI (F) to Micro HDMI Converter

Micro B Usb Cable

For this project, I designed a custom PCB using EasyEDA, a user-friendly online PCB design tool. EasyEDA allows for schematic capture, PCB layout, and even simulation.

Once the PCB design was finalized, I placed an order with NextPCB, a reliable PCB manufacturer that provides high-quality fabrication services. They offer quick turnaround times and precise manufacturing, ensuring that the PCB meets the required specifications.

Steps to Design and Order:

1. Open EasyEDA and create a new project.

2. Design the schematic for the circuit.

3. Convert the schematic to a PCB layout and arrange the components.

4. Route the PCB traces and set design rules.

5. Generate Gerber files, which are required for manufacturing.

6. Upload the Gerber files to NextPCB and place the order.

Once the custom PCB arrives, the next step is to solder the necessary components onto it. This project involves creating a continuity tester, so we will be soldering the following components:

Required Components:

• Buzzer (to indicate continuity)

• LED (for visual indication)

• 1K Resistor (current limiting for the LED)

Soldering Steps:

1. Prepare the PCB: Ensure the PCB is clean and free of dust.

2. Place the Components: Insert the buzzer, LED, and 1K resistor into their designated positions on the PCB.

3. Solder the Components:

• Heat the pad and component lead with a soldering iron.

• Apply a small amount of solder to create a strong connection.

4. Trim Excess Leads: Use wire cutters to trim any excess component legs.

5. Inspect Solder Joints: Ensure there are no cold solder joints or bridges between connections.

Once all components are soldered, the board is ready for testing. In the next step, we will verify the circuit functionality.

In this step, we integrate the XL4015 buck converter module and a digital DC voltage & amp meter to make the device multi-purpose. The XL4015 module allows voltage adjustment using a potentiometer, while the VA meter displays real-time voltage and current readings.

Components Used:

• XL4015 Step-Down (Buck) Converter Module (Adjustable voltage regulator)

• DC Voltage & Amp Meter Module (Digital display for voltage & current)

Steps to Connect:

1. Open the VA Meter Case:

• Carefully remove the plastic casing of the digital voltage & amp meter to expose the circuit board.

• This allows for direct PCB mounting inside the custom-built device.

2. Mount the XL4015 Module:

• Place the XL4015 module onto the PCB.

• Secure connections for input power (Vin) and output (Vout).

3. Fix the VA Meter PCB:

• Secure the exposed VA meter PCB onto the custom PCB.

• Ensure it is properly aligned for visibility and stability.

4. Wire the DC VA Meter Module:

• Connect the input power of the VA meter to the output of the XL4015.

• Attach the current sensor in series with the output load to measure amps.

5. Adjust the Output Voltage:

• Turn the potentiometer on the XL4015 to vary the voltage.

• Observe changes on the digital VA meter display in real time.

6. Verify Functionality:

• Ensure the voltage adjusts smoothly.

• Confirm the amp meter reads current properly.

By removing the VA meter case and mounting it directly onto the PCB, the design becomes more compact and integrated, making the device efficient and user-friendly.

we integrate two USB sockets to provide 5V output for powering external devices. One USB port is dedicated to a Raspberry Pi board, and the other powers a DFRobot 7-inch HDMI display.

To achieve this, we use a DFRobot 12V to 5V 8A power module, which efficiently steps down the 12V input to a stable 5V high-current output.

Components Used:

• 2 x USB sockets (for 5V output)

• DFRobot 12V to 5V 8A step-down module (for power conversion)

Wiring Steps:

1. Mount the USB Sockets:

• Secure the two USB sockets onto the PCB.

• Ensure proper alignment for easy external connections.

2. Connect the Power Module:

• Input: Connect 12V power supply (Vin) to the DFRobot 12V to 5V converter.

• Output: Connect the 5V output to both USB sockets.

3. USB Power Distribution:

• USB 1 → Raspberry Pi Board (provides stable 5V power).

• USB 2 → DFRobot 7-inch HDMI Display (ensures proper display power).

4. Verify Power Output:

• Measure the 5V output from each USB socket using a multimeter.

• Ensure proper voltage and current delivery.

This setup ensures stable and high-current 5V output, making the device suitable for powering both the Raspberry Pi and an external HDMI display efficiently.

we integrate three 18650 battery holders (SMD type) onto the PCB to provide a backup power source. Each holder is designed for a 3.7V 18650 lithium-ion battery

Components Used:

• 3 x SMD 18650 battery holders

• 3 x 3.7V 18650 lithium-ion batteries

Steps to Install:

1. Mount the Battery Holders:

• Solder the SMD 18650 holders onto the designated PCB pads.

• Ensure proper alignment and secure solder joints.

2. Insert the 18650 Batteries:

• Place three 18650 batteries into the holders.

• Ensure correct polarity (positive and negative terminals).

To monitor the battery status, we integrate a 3S battery level indicator module directly onto the PCB. This ensures real-time monitoring of the 18650 battery pack’s charge level, helping prevent over-discharge and ensuring efficient power management.

Components Used:

• 1 x 3S Battery Level Indicator Module (LED bar display)

• 18650 3S Battery Pack (3 x 3.7V cells in series)

Steps to Install:

1. Mount the Battery Level Indicator:

• Solder the 3S battery indicator module onto the PCB.

• Ensure proper alignment and strong solder joints.

2. Connect to Battery Pack:

• Wire the positive (+) and negative (-) terminals of the 3S battery pack to the indicator module.

• Connect the balance leads to the respective battery taps (B1, B2, B3).

3. Test the Indicator Functionality:

• Turn on the device and observe the LED indicators.

• Verify that the LEDs display the correct battery charge level.

4. Ensure Safe Operation:

• Make sure the indicator does not drain the battery excessively when idle.

• Optionally, add a switch to enable or disable the indicator manually.

By adding a battery level indicator, the device provides a clear visual representation of battery status, making it easier to manage power usage.

To enhance the device’s functionality, we add a 12V battery charging socket and four banana sockets to the PCB. The charging socket allows for external 12V power input, while the banana sockets provide easy access to variable power output and continuity testing.

Components Used:

• 1 x 12V Battery Charging Socket (for external power input)

• 4 x Banana Sockets (for power output and continuity testing)

Installation Steps:

1. Mount the 12V Charging Socket:

• Secure the 12V charging socket onto the PCB.

• Solder the terminals firmly for a reliable connection.

• Ensure proper polarity to avoid reverse connections.

2. Install the Banana Sockets:

• Solder four banana sockets onto the PCB.

• Arrange them in two pairs:

• Pair 1: Variable power supply output (adjustable voltage from XL4015).

• Pair 2: Continuity test probes.

3. Wire the Connections:

• Charging Socket: Connect it to the battery management circuit for safe charging.

• Variable Power Output Pair: Connect to the XL4015 module output for adjustable voltage.

• Continuity Test Pair: Connect to the buzzer, LED, and resistor setup for testing continuity.

4. Test Functionality:

• Plug in a 12V charger and confirm the battery charges correctly.

• Use a multimeter to check the voltage output from the banana sockets.

• Verify the continuity tester works by shorting its terminals.

By integrating a charging socket and banana connectors, the device becomes a complete power and testing station, allowing easy access to adjustable power output and continuity checking.

1. Check Component Placement:

• Ensure all components (buzzer, LED, resistors, XL4015 module, USB sockets, battery holders, and banana sockets) are inserted correctly on the PCB.

• Double-check polarity-sensitive components like LEDs, capacitors, and modules.

2. Soldering the Connections:

• Flip the PCB and heat each pad with the soldering iron.

• Apply a small amount of solder wire to secure each leg.

• Ensure the solder forms a smooth, shiny joint without excessive buildup.

3. Trim Excess Component Legs:

• Use wire cutters to trim extra component legs close to the board.

• Avoid cutting too close, as it may weaken the connection.

4. Inspect and Fix Any Issues:

• Check for cold solder joints (dull or cracked solder).

• Look for short circuits caused by solder bridges between pads.

• Use a multimeter to test continuity and verify correct connections.

5. Final Cleaning:

• Use isopropyl alcohol and a brush to clean the PCB surface.

• This removes flux residue and prevents possible short circuits.

By carefully soldering the component legs on the PCB backside, we ensure a durable and reliable circuit, ready for final assembly and testing.

To manage and protect the 18650 battery pack, we integrate a 3S 10A Battery Management System (BMS) module on the backside of the PCB. This ensures safe charging, overcurrent protection, and balanced discharge of the 3-cell battery pack.

Components Used:

• 1 x 3S 10A BMS Module (for battery protection)

Steps to Install and Solder:

1. Position the BMS on the PCB Backside:

• Locate the designated area on the backside of the PCB for the BMS module.

• Ensure proper orientation for battery and power connections.

2. Solder the BMS Module to the PCB:

• Align the B+ (Battery Positive), B- (Battery Negative), and B1/B2 (balance connections) to the PCB pads.

• Solder the BMS terminals securely to the PCB, ensuring a solid connection.

3. Connect the Battery Pack:

• B+ → Connect to the positive terminal of the 3S battery pack.

• B- → Connect to the negative terminal of the battery pack.

• B1 & B2 → Connect to the balance points between battery cells.

4. Connect Power Output:

• P+ (Output Positive) & P- (Output Negative) → Connect to the power distribution circuit (such as the XL4015 module or USB sockets).

• This ensures that all power output is regulated and protected by the BMS.

5. Test the BMS Functionality:

• Check voltage levels across the battery pack using a multimeter.

• Ensure balanced charging across all three cells.

• Verify overcharge and overcurrent protection by testing load conditions.

By mounting the BMS on the PCB backside, we keep the main PCB surface clear, while ensuring safe and efficient battery management.

After completing all soldering and component mounting, it’s essential to clean the PCB to remove any flux residue, dust, or solder splashes. This improves circuit reliability, prevents short circuits, and gives the board a professional finish.

Steps to Clean the PCB:

1. Choose the Right Cleaning Liquid:

• Use isopropyl alcohol (IPA) (90% or higher) or a dedicated PCB cleaner.

• Avoid using water, as it can damage components.

2. Apply the Cleaning Liquid:

• Use a small brush, cotton swab, or lint-free cloth.

• Dip it in IPA and gently scrub the PCB, focusing on soldered joints.

3. Remove Excess Flux and Dirt:

• Clean around soldered areas, especially on the backside of the PCB where excess flux may be present.

• Use a soft brush to remove any solidified flux residues.

4. Dry the PCB Properly:

• Allow the PCB to air dry for a few minutes.

• You can use a compressed air blower or a soft cloth to speed up drying.

5. Final Inspection:

• Check for any leftover residue, solder bridges, or loose connections.

• Use a magnifying glass if needed to inspect fine solder joints.

By cleaning the PCB neatly, the board looks professional, reduces risk of shorts, and ensures long-term reliability.

To securely mount the Raspberry Pi 4B onto the top side of the PCB, we use spacers (standoffs). These spacers provide stability, ensure proper ventilation, and prevent short circuits between the Pi and PCB.

Components Used:

• 4 x M2.5 or M3 Spacers (Standoffs) (Metal or Nylon)

• 4 x Screws & Nuts (Matching the spacers)

Installation Steps:

1. Mark the Mounting Holes:

• Align the Raspberry Pi 4B mounting holes with the designated holes on the PCB.

2. Install the Spacers:

• Screw the spacers into the PCB from the top side.

• Ensure they are tightly secured to prevent wobbling.

3. Mount the Raspberry Pi 4B:

• Place the Raspberry Pi 4B onto the spacers.

• Secure it using the screws and nuts.

4. Check for Clearance & Connections:

• Ensure the GPIO pins, USB, HDMI, and power ports are accessible.

• Make sure the bottom of the Raspberry Pi does not touch the PCB to prevent short circuits.

By using spacers, the Raspberry Pi 4B is securely mounted, allowing proper airflow and ensuring safe operation without shorting components.

To simplify GPIO connections and enhance accessibility, we install the DFRobot Raspberry Pi 4B GPIO Terminal Block HAT. This HAT allows easy wire connections to the Raspberry Pi’s GPIO pins without soldering.

Components Used:

• 1 x DFRobot Raspberry Pi 4B GPIO Terminal Block HAT

• 4 x Spacers (Same as Raspberry Pi mounting)

• 4 x Screws & Nuts

Installation Steps:

1. Mount the HAT on Raspberry Pi:

• Align the 40-pin GPIO connector of the HAT with the Raspberry Pi’s GPIO header.

• Press it down firmly to ensure a secure connection.

2. Secure the HAT with Spacers:

• Use the same spacers as the Raspberry Pi mounting to support the HAT.

• Fix the HAT using screws and nuts for stability.

3. Verify GPIO Pin Accessibility:

• Check that all GPIO terminal block connections are properly labeled.

• Ensure there are no loose connections that could cause short circuits.

4. Test GPIO Functionality:

• Connect a test wire to a GPIO pin and control it using a simple Python script.

• Verify that input and output signals work correctly.

By adding the DFRobot GPIO Terminal Block HAT, we make GPIO wiring easier, improving reliability and accessibility for further development.

To protect the PCB and Raspberry Pi setup, we use a custom laser-cut acrylic case. The acrylic case ensures dust protection, structural stability, and a professional finish, while allowing proper airflow.

Components Used:

• 1 x Custom Laser-Cut Acrylic Case (Top & Bottom Panels + Side Walls)

• 4 x Spacers (For PCB & Raspberry Pi Mounting)

• 8 x Screws & Nuts (For securing the acrylic layers)

Installation Steps:

1. Prepare the Laser-Cut Acrylic Pieces:

• Ensure the acrylic sheet is properly cut with holes for:

• PCB mounting

• Raspberry Pi & HAT

• USB, HDMI, and GPIO access

• Cooling vents (if needed)

2. Mount the PCB onto the Acrylic Base:

• Align the PCB with the mounting holes in the bottom acrylic sheet.

• Secure it using spacers, screws, and nuts.

• Ensure no electrical contact between the PCB and the acrylic to prevent short circuits.

3. Install the Raspberry Pi and HAT:

• Fit the Raspberry Pi with the GPIO Terminal Block HAT inside the case.

• Use spacers to maintain proper distance from the acrylic walls.

4. Attach the Top Acrylic Cover:

• Align the top acrylic sheet with the case.

• Secure it using screws at each corner.

5. Check Port Accessibility & Ventilation:

• Ensure all ports (USB, HDMI, Power, GPIO) remain accessible.

• If needed, add air vents or a small cooling fan for heat dissipation.

6. Final Inspection:

• Confirm all components are securely mounted.

• Verify the case is sturdy and there are no loose connections.

By using a laser-cut acrylic case, the device is protected, neatly enclosed, and easy to transport, while still allowing full access to components.

Now that the Raspberry Pi 4B and all components are mounted, it’s time to provide power using a Type-A to Type-C cable. This step ensures proper power delivery to the Raspberry Pi for stable operation.

Components Used:

• 1 x Type-A to Type-C Cable

• 5V Power Source (USB output from PCB, DFRobot 12V to 5V 8A module)

Steps to Connect the Power Supply:

1. Identify the Power Source:

• The 12V input is converted to 5V using the DFRobot 12V to 5V 8A module.

• The USB port on the PCB provides a stable 5V output for the Raspberry Pi.

2. Plug in the Type-A to Type-C Cable:

• Connect the Type-A end of the cable to the USB power output on the PCB.

• Connect the Type-C end to the Raspberry Pi 4B power input port.

3. Power On the System:

• Switch on the main power supply.

• Check the Raspberry Pi’s power LED—it should light up, indicating power is received.

4. Verify Proper Voltage and Current:

• Use a multimeter to check that the USB output is supplying 5V correctly.

• Ensure the power does not drop under load when the Raspberry Pi is running.

5. Check Raspberry Pi Booting:

• If a display is connected, verify that the Raspberry Pi boots properly.

• If the Raspberry Pi does not turn on, check cable connections, power output, and voltage levels.

By using a Type-A to Type-C cable, we ensure stable power delivery to the Raspberry Pi, allowing smooth operation without power fluctuations.

Now, we connect the DFRobot 7-inch HDMI display to the Raspberry Pi 4B for visual output. The display requires 5V power and an HDMI connection for video output.

Components Used:

• 1 x DFRobot 7-inch HDMI Display

• 1 x HDMI to Micro-HDMI Cable (for video connection)

• 1 x 5V Power Connection (from PCB USB socket)

Steps to Connect the Display:

1. Power the Display:

• The display needs 5V power, which is supplied from the USB socket on the PCB.

• Plug a USB Type-A to Type-C or Micro-USB cable into the 5V output on the PCB.

• Connect the other end to the display’s power input port.

2. Connect HDMI Cable:

• Use a Micro-HDMI to HDMI cable.

• Insert the Micro-HDMI end into the Raspberry Pi’s HDMI port (HDMI 0, the primary port).

• Insert the HDMI end into the DFRobot display’s HDMI input.

Mounting the DFRobot HDMI Display Inside the Acrylic Case

To securely install the DFRobot 7-inch HDMI display inside the custom acrylic case, we will use spacers and screws. This ensures a stable and professional look while keeping all components safely enclosed.

Components Used:

• 1 x DFRobot 7-inch HDMI Display

• 4 x Spacers (Nylon or Metal, for proper clearance)

• 4 x Screws & Nuts (For securing the display)

• 1 x USB Cable (For power connection to the PCB’s 5V socket)

Steps to Mount the Display and Connect Power:

1. Position the Display in the Acrylic Case:

• Align the DFRobot HDMI display inside the front panel cutout of the acrylic case.

• Ensure the screen fits properly without pressure on the edges.

2. Secure the Display with Spacers & Screws:

• Use spacers to create a small gap between the display and acrylic panel, preventing pressure damage.

• Insert screws through the acrylic and spacers, securing them with nuts at the back.

3. Connect the HDMI Cable to Raspberry Pi:

• Plug the Micro-HDMI end into the Raspberry Pi’s HDMI 0 port.

• Connect the HDMI end to the display’s HDMI input.

4. Power the Display via USB Socket:

• Use a USB cable to connect the display’s power port to the 5V USB socket on the PCB.

• Ensure the cable is neatly routed to avoid interference with other components.

5. Final Assembly & Testing:

• Secure the back panel of the acrylic case with screws.

• Power on the system and verify that the display turns on and shows output.

By mounting the display inside the acrylic case, we achieve a clean and professional design, keeping all components protected and well-organized.

Now, we install the operating system (OS) on a microSD card and insert it into the Raspberry Pi 4B. You can use Raspberry Pi OS or any other OS of your choice.

Components Used:

• 1 x MicroSD Card (16GB or higher, Class 10 recommended)

• 1 x Card Reader (For flashing the OS)

• 1 x Transparent Acrylic Top Cover (With Proper Holes for Access)

Steps to Install the OS & Insert the Memory Card:

1. Download Raspberry Pi OS (or Any OS):

• Go to the official Raspberry Pi website.

• Download Raspberry Pi OS (Lite/Desktop) or use an alternative OS like Ubuntu, RetroPie, or Kali Linux.

2. Flash the OS to the MicroSD Card:

• Use Raspberry Pi Imager or balenaEtcher to write the OS to the microSD card.

• Insert the microSD card into a card reader and connect it to your PC.

• Open Raspberry Pi Imager, select the OS, choose the microSD card, and click Write.

• Wait for the process to complete, then safely remove the card.

3. Insert the MicroSD Card into the Raspberry Pi:

• Locate the microSD card slot on the Raspberry Pi 4B (underside).

• Insert the microSD card gently until it clicks into place.

4. Secure the Transparent Acrylic Top Cover:

• Align the acrylic sheet with the mounting holes.

• Use screws to secure it, ensuring proper ventilation holes are in place.

• The transparent cover allows visibility while protecting the components.

5. Power On and Test the OS:

• Connect power and turn on the Raspberry Pi.

• If connected to a display, the OS should boot up properly.

• Complete the initial setup (WiFi, SSH, updates) as needed.

By installing the OS and adding a transparent acrylic top, we ensure the device is functional, protected, and visually appealing.

Now that all components are assembled and powered, your all-in-one portable device is ready for use! This device can be used for coding, programming, variable power output, and continuity testing.

Final Testing Steps:

1. Turn on the Power Switches:

• Ensure the main power switch is ON.

• Check that the Raspberry Pi boots up and the display is working.

2. Verify the Variable Power Supply:

• Adjust the XL4015 module’s potentiometer to change the voltage.

• Confirm that the digital VA meter displays the correct voltage and current readings.

• Use a multimeter to cross-check the output.

3. Test the Continuity Tester:

• Connect a wire or resistor to the continuity test terminals.

• If the circuit is closed, the buzzer and LED should activate.

4. Check the USB Power Outputs:

• Plug in a Raspberry Pi board or another device into the 5V USB sockets.

• Verify that the connected device receives stable power.

5. Confirm the Battery System:

• Check the 18650 battery charge level indicator.

• Ensure that the BMS (Battery Management System) is functioning properly for safe charging and discharging.

Usage Scenarios:

✅ Coding & Programming:

• Use the Raspberry Pi for software development, IoT projects, and learning.

✅ Variable Power Supply:

• Adjust the XL4015 module to provide custom voltage outputs for different projects.

✅ Continuity Testing:

• Quickly check wires, circuits, and components for electrical continuity.

✅ Portable Design:

• Powered by 18650 batteries, making it perfect for on-the-go electronics work.

For a complete step-by-step build guide and demonstration, check out my YouTube videos! 📌

👉 [CLICK HERE]