Ultimate DIY Laboratory PSU From a Gaming PC PSU

For the longest time, I’ve been relying on a mix of 12V and 24V chargers to power my various DIY projects. While they got the job done, I often found myself wishing for a more versatile and robust power solution. It was during a routine cleanup that I stumbled upon a couple of old gaming power supplies (PSUs) and realized their untapped potential. These gaming PSUs, known for their power and reliability, sparked an idea: why not transform them into an ultimate laboratory-grade variable power supply unit (PSU)?

In this tutorial, I will guide you through the process of converting a standard gaming PC power supply into a fully adjustable power source. This DIY power supply unit is not only cost-effective but also incredibly customizable, making it perfect for any project that requires different voltage levels. Whether you’re a seasoned DIY enthusiast or just getting started, this guide will help you create a powerful tool for your workshop that meets all your power needs. Let’s dive in and build this ultimate laboratory variable PSU together!

Reused Material:

Gaming PC PSU

3D Printed Material:

Corners:

12V USB C Chargers + Oled Screen Holder

Frame Front:

Frame Back:

Bought Material:

1800W boost converter: https://www.aliexpress.com/item/1005005724779122.html?spm=a2g0o.order_list.order_list_main.311.159d1802PUMKJN

10A 100V metering units (x3): https://www.aliexpress.com/item/1005005631543388.html?spm=a2g0o.order_list.order_list_main.300.159d1802PUMKJN

50A 100V metering units (x2): https://www.aliexpress.com/item/1005005954159137.html?spm=a2g0o.order_list.order_list_main.306.159d1802PUMKJN

Banana connectors male female (x20): https://www.aliexpress.com/item/1005005988853903.html?spm=a2g0o.order_list.order_list_main.291.159d1802PUMKJN

Fuse Holders (x12): https://www.aliexpress.com/item/4000318730279.html?spm=a2g0o.order_list.order_list_main.296.159d1802PUMKJN

Fuses: https://www.aliexpress.com/item/1005004114014014.html?spm=a2g0o.order_list.order_list_main.286.159d1802PUMKJN

Crocodile Connectors: https://www.aliexpress.com/item/1005005195480100.html?spm=a2g0o.order_list.order_list_main.224.159d1802PUMKJN

Plywood 1200 x 600 mm

Carbon fiber Vinyl wrap

M3 Screws

M3 Nuts

Tools Used:

Electric Drill

Dremel 3000

Wood saw

Soldering iron

Heat Gun

3D printer

A Complete Guide On Why And How I Built It!

Choose the Power Supply:

• Selection Criteria: Select a gaming PC power supply capable of handling up to 500W. These power supplies are robust and designed to provide steady currents up to 50A, offering outputs of 3.3V, 5V, and 12V, which are perfect for a variety of DIY projects.

Modify the Wires:

• Keep Original Wires: It's generally better to keep the original wires of the power supply intact, as they are already properly insulated and labeled for their specific outputs. Soldering these wires can be tedious and time-consuming, so maintaining the original wiring simplifies the process.
• Connecting the Green Wire: To turn on the PSU without a PC, you need to connect the green wire (PS_ON) to any black ground wire. This trick enables the PSU to power up as soon as it is plugged into an outlet.
• Steps to Connect:

1. Identify the green wire (PS_ON) and a black ground wire in the main connector.
2. Use a paperclip or a small piece of wire to bridge the connection between the green wire and the ground wire.
3. Ensure the connection is secure to avoid any loose contacts.

• Cable Management: Organize and label the wires to avoid confusion later. You might want to use cable ties or Velcro straps to keep them neat.

Test the PSU:

• Initial Power-On Test: Once the green wire is connected to the ground, plug the power supply into an outlet.
• Verification: Ensure the PSU powers up correctly. You should hear the fan spinning and see any indicator lights turning on.
• Voltage Check: Use a multimeter to check the voltage outputs (3.3V, 5V, and 12V) to ensure they are within the expected range. This step confirms that the power supply is functioning properly before you proceed with further modifications.

Select the Boost Module:

• Choosing the Right Module: For higher voltage requirements beyond what the PC power supply can provide, select a robust boost module. An 1800W boost module is ideal for this project due to its capability to handle at least 40A of current, providing a significant power boost for demanding applications.
• Considerations: Ensure the module you select is compatible with your power supply’s outputs and can handle the desired voltage and current levels. Look for modules with good heat dissipation features and reliable performance ratings.

Modify Potentiometers:

• Understanding the Need: Boost modules often come with potentiometers soldered directly onto the board for voltage adjustment. For greater flexibility and ease of use, it's beneficial to install connectors that allow you to swap out potentiometers as needed.
• Steps to Install Connectors:

1. Desolder Original Potentiometer: Carefully desolder the potentiometer from the boost module using a soldering iron. Take care not to damage the PCB.
2. Install Connectors: Solder female connectors onto the points where the potentiometer was originally attached. Ensure the connectors are securely in place and the connections are strong.
3. Prepare Potentiometers: Solder male connectors to the ends of the potentiometers you plan to use. This allows you to easily plug and unplug different potentiometers based on your voltage adjustment needs.

• Flexibility: This modification provides the ability to replace or adjust potentiometers without having to desolder and resolder each time, adding versatility to your power supply unit.

Test the Module:

• Initial Setup: Connect the modified boost module to the PC power supply. Ensure that all connections are secure and there are no loose wires.
• Connect Potentiometers: Plug in the potentiometers into the female connectors installed on the boost module. Make sure they are firmly connected.
• Power On and Test:

1. Power On: Turn on the power supply and the boost module.
2. Voltage Adjustment: Adjust the potentiometers to vary the output voltage. Use a multimeter to measure the voltage output and verify that it changes smoothly and reaches the desired levels.
3. Check for Stability: Ensure that the boost module operates stably at different voltage levels without overheating or showing signs of instability.

• Safety Check: Monitor the module for any warning indicators, such as overheating or excessive current draw. If any issues arise, immediately turn off the power and troubleshoot the connections.

Download Templates:

• Accessing Templates: Obtain the detailed PDF templates provided in the project description. These templates are designed to guide you in cutting and drilling the plywood accurately.
• Print Templates: Print the templates at 100% scale to ensure the dimensions are precise. Verify that the printed templates match the intended measurements before proceeding.
• Prepare Work Area: Set up a clean and spacious work area where you can lay out the templates and work on the plywood comfortably.

Cut Plywood:

• Select Plywood: Choose high-quality plywood that is easy to handle and cut. Plywood with a smooth surface and sufficient thickness will provide better durability and finish.
• Transfer Template: Tape the printed templates onto the plywood sheets. Ensure the templates are securely attached and properly aligned.
• Drill Holes:

1. Mark Drill Points: Use a pencil or marker to mark the drill points on the plywood according to the templates.
2. Drill Pilot Holes: Start by drilling pilot holes at the marked points. These smaller holes will guide the larger drill bits and prevent the wood from splintering.
3. Expand Holes: Use the appropriate drill bit sizes to expand the pilot holes to their final dimensions. Take your time to ensure the holes are clean and accurately positioned.

• Cut Slots and Shapes:

1. Outline Shapes: Use a ruler and a straightedge to draw the outlines of the slots and shapes to be cut, based on the template markings.
2. Cutting Method: Employ a jigsaw or a hand saw to carefully cut out the slots and shapes. For more intricate cuts, consider using a coping saw or a rotary tool.
3. Smoothing Edges: After cutting, use sandpaper to smooth the edges and remove any roughness or splinters. This will give the plywood a polished look and make it safer to handle.

Wrap in Vinyl:

• Choose Vinyl: Select carbon fiber vinyl for a sleek and professional appearance. Ensure the vinyl is of high quality and has strong adhesive backing.
• Prepare Plywood Surface: Clean the surface of the plywood to remove any dust or debris. A smooth, clean surface will help the vinyl adhere better.
• Cut Vinyl Sheets:

1. Measure and Cut: Measure the dimensions of the plywood pieces and cut the vinyl sheets slightly larger than these dimensions. This will allow for easy handling and wrapping.
2. Peel and Stick: Peel off a portion of the vinyl backing and start applying it to the plywood, beginning from one edge.
3. Smooth Application: Use a squeegee or a flat tool to smooth out the vinyl as you go, pressing out any air bubbles and ensuring even adhesion.
4. Wrap Edges: Wrap the excess vinyl around the edges of the plywood and press it firmly to secure.

• Cut Out Openings:

1. Mark Openings: Use a sharp utility knife to carefully cut out the openings for the holes and slots in the plywood. Follow the edges of the cutouts to ensure precision.
2. Smooth Edges: Smooth the edges of the vinyl around the cutouts to ensure a clean and professional finish.

• Final Inspection: Inspect the wrapped plywood for any imperfections or air bubbles. Smooth out any remaining bubbles and ensure the vinyl is securely adhered to the entire surface.

Position Metering Units:

• Insert Metering Units: Place the metering units into the pre-cut holes in the control panel. Depending on your requirements, you can have one variable unit and four 12V units, or like my setup, one variable unit, two 12V units, one 5V unit, and one 3.3V unit.
• Secure the Units: Ensure each metering unit fits snugly into its respective slot. If necessary, adjust the slots slightly for a perfect fit.

Install Connectors and Switches:

• Place Banana Connectors: Insert banana connectors into the pre-drilled holes. These connectors will serve as the output terminals for your power supply.
• Secure Banana Connectors: Tighten the nuts and washers provided with the connectors to secure them firmly in place.
• Position Switches: Place the switches beside each metering unit into the designated holes. These switches will control the power flow to each unit.
• Secure Switches: Use the provided nuts to secure the switches to the control panel, ensuring they are firmly attached.

Add Fuses:

• Install Fuse Holders: Insert the fuse holders into the holes cut previously on the control panel.
• Secure with Glue: Apply a small amount of strong adhesive or epoxy glue around the base of each fuse holder to secure it in place. Ensure the holders are firmly attached and allow the glue to dry completely.
• Insert Fuses: Once the glue has dried, insert the appropriate fuses into the holders. This will provide protection for each power output, enhancing the safety of your power supply unit.

Insert Nuts into Corners:

• Heat the Holes: Using a heat gun or a soldering iron, carefully heat the holes in the 3D printed corners. The plastic should become soft enough to allow the insertion of the nuts without excessive force.
• Press in Nuts:

1. Position Nut: Place the nut over the softened hole.
2. Insert Nut: Gently press the nut into the hole while the plastic is still pliable. Ensure the nut is aligned correctly and inserted flush with the surface.
3. Cool and Set: Allow the plastic to cool and harden around the nut, securing it in place. This process prevents the nut from spinning when you insert the screw later.

Assemble Frame:

• Position Corners:

1. Align Corners: Arrange the 3D printed corners at the intersections of the plywood panels to form the frame. Ensure the holes for screws and nuts are properly aligned.
2. Attach Panels: Insert screws through the holes in the plywood panels and into the nuts embedded in the corners. Use a screwdriver to tighten the screws, securing the panels to the corners.

• Construct Frame: Continue this process for all corners, assembling the frame piece by piece until all sides are securely attached. Ensure the frame is square and stable.

Position Components:

• Secure the PSU:

1. Position PSU: Place the power supply unit (PSU) inside the frame in the designated spot. Ensure it fits securely and aligns with any pre-drilled holes for mounting.
2. Mount PSU: Use screws to secure the PSU to the frame. Tighten the screws to ensure the PSU is firmly attached and does not move.

• Install Boost Module:

1. Position Boost Module: Place the boost module inside the frame. Ensure it is positioned to allow easy access to the input and output connections, as well as any adjustment points like potentiometers.
2. Secure Module: Use screws or brackets to attach the boost module to the frame. Make sure it is securely fastened to prevent any movement during operation.

• Organize Wiring:

1. Route Wires: Plan and route the wires from the PSU and boost module to their respective connection points. Use cable ties or clips to organize and secure the wires, keeping them neat and preventing tangling.
2. Label Wires (Optional): Label each wire according to its voltage level and connection point. This will help during the wiring and troubleshooting process, ensuring correct and safe connections.

Solder Connections:

• Prepare Tools: Gather a soldering iron, solder, flux, wire strippers, and heat shrink tubing.
• Identify Points: Use your wiring diagram to identify connections on the control panel.
• Strip and Flux Wires: Strip the wire ends, apply flux to them and the connection points.
• Solder Wires:

1. Heat and Apply Solder: Heat the connection point with the soldering iron, then apply solder until it flows onto the wire and pad.
2. Cool and Inspect: Let the solder cool, forming a solid connection. Ensure joints are smooth and shiny.

• Protect Joints: Cover solder joints with heat shrink tubing and shrink it with a heat gun.

Route Wires:

• Plan Routes: Organize wires by voltage levels to avoid interference.
• Use Cable Ties: Secure wires along planned routes with cable ties or clips.
• Pass Through Holes: Thread wires through pre-drilled holes in the frame.
• Label Wires: Label or color-code wires for easy identification.

Connect Wires:

• Identify Terminals: Use the wiring diagram to find connection points on the PSU and boost module.
• Prepare and Attach:

1. Strip and Tin Wires: Strip and tin the wire ends.
2. Connect to PSU: Attach wires to the appropriate PSU terminals and tighten screws.
3. Connect to Boost Module: Attach wires to the boost module’s input and output terminals.

• Verify Connections: Double-check that all wires are securely connected and match the wiring diagram.

Install ESP8266:

• Select Mounting Location: Choose a suitable spot on the frame to mount the ESP8266 module where it won't interfere with other components.
• Secure Module: Use screws, adhesive, or zip ties to attach the ESP8266 module firmly to the frame. Ensure it is positioned for easy access to power and data connections.
• Connect Power: Solder or attach power wires from the PSU to the ESP8266 module, ensuring correct voltage and polarity.
• 
  

Attach Sensors:

• Select Sensor Types: Use temperature and humidity sensors, such as the DHT22 or DS18B20, that are compatible with the ESP8266.
• Position Sensors: Place the sensors near critical points like the main PSU and boost module to monitor temperature and humidity where it’s most needed.
• Secure Sensors: Attach the sensors using screws, adhesive, or zip ties. Ensure they are positioned securely and their wires are routed neatly.
• Connect to ESP8266:

1. Wiring: Connect the sensor data pins to the appropriate GPIO pins on the ESP8266. Follow the sensor’s wiring guide for correct connections.
2. Power: Connect the power and ground wires of the sensors to the corresponding pins on the ESP8266.

Display Readings:

• Connect OLED Screen:

1. Wiring: Connect the OLED screen to the ESP8266 using I2C (SDA and SCL pins) or SPI, depending on your OLED screen type.
2. Power: Connect the OLED screen’s power and ground wires to the ESP8266.

• Upload Code:

1. Prepare Code: Write or download a suitable code to read sensor data and display it on the OLED screen. You can find many examples online for ESP8266 sensor data display.
2. Upload Code: Use the Arduino IDE or another compatible platform to upload the code to the ESP8266. Ensure the code is configured to read the specific sensors you are using.

• Test Functionality:

1. Power On: Turn on the power supply and check that the ESP8266 and sensors power up correctly.
2. Monitor Readings: Verify that the OLED screen displays the correct temperature and humidity readings. Ensure the data updates in real-time.

Identify Shunt Requirements:

• Determine Need: Two of your metering units require a separate shunt to accurately measure higher currents.
• Choose Shunt: Select a heavy-duty shunt appropriate for your current measurement needs, typically rated for up to 50A.

Select Mounting Location:

• Find Free Space: Identify a free space inside the housing where the shunt can be securely mounted without interfering with other components.
• Ensure Accessibility: Ensure the shunt is easily accessible for wiring and any future maintenance.

Mount the Shunt:

• Position Shunt: Place the shunt in the selected location.
• Mark Holes: Mark the mounting holes on the housing where the shunt will be secured.
• Drill Holes: Drill holes at the marked positions if necessary.
• Secure Shunt: Use screws or bolts to attach the shunt firmly to the housing.

Connect the Shunt:

• Refer to Diagram: Use the provided wiring diagram to understand the correct connections for the shunt.
• Prepare Wires:

1. Strip Ends: Strip the ends of the wires that will be connected to the shunt.
2. Tin Wires: Apply a small amount of solder to the stripped ends to improve the connection.

• Connect to Shunt:

1. Positive Connection: Attach the wire from the positive terminal of the metering unit to one side of the shunt.
2. Negative Connection: Attach the wire from the negative terminal of the metering unit to the other side of the shunt.
3. Secure Connections: Tighten the screws or bolts on the shunt to secure the wires firmly in place.

• Insulate Connections: Use heat shrink tubing or electrical tape to insulate the connections and prevent short circuits.

Verify Connections:

• Check Wiring: Double-check that all connections are secure and match the wiring diagram.
• Test Continuity: Use a multimeter to test the continuity of the connections, ensuring there are no breaks or short circuits.
• Label Wires: Label the wires connected to the shunt for easy identification and future reference.

Attach Side Panels:

• Prepare Panels: Ensure all side panels are cut to the correct dimensions and have integrated fans where necessary for cooling.
• Position Panels:

1. Align Panels: Align the plywood side panels with the edges of the frame, ensuring all holes for screws and fans match up.
2. Secure Fans: If your side panels include fans, make sure the fans are properly secured in their slots with screws, and wires are routed appropriately.

• Screw Panels In Place:

1. Insert Screws: Use screws to attach the panels to the frame. Start by placing screws in the corners, then add additional screws along the edges to ensure the panels are firmly attached.
2. Tighten Screws: Use a screwdriver to tighten each screw, securing the panels firmly to the frame.

Finish with Vinyl:

• Cut Vinyl Sheets: Measure and cut carbon fiber vinyl sheets to fit the remaining uncovered plywood parts.
• Apply Vinyl:

1. Peel and Stick: Peel off a small section of the vinyl backing and begin applying it to the plywood surface.
2. Smooth Out: Use a squeegee or a flat tool to smooth the vinyl as you go, pressing out any air bubbles and ensuring a smooth finish.

• Wrap Edges: Wrap the excess vinyl around the edges of the plywood and press firmly to secure.
• Trim Excess: Use a sharp utility knife to carefully trim any excess vinyl, ensuring clean edges around openings and corners.

Add Decorative Frames:

• Prepare Frames: Ensure your 3D printed frames for the front and back are clean and ready to install.
• Position Frames:

1. Align Frames: Align the frames with the edges of the control panel and the back of the unit.
2. Cover Imperfections: Ensure the frames cover any gaps or rough edges for a clean and professional look.

• Secure Frames:

1. Apply Adhesive: Apply a small amount of strong adhesive or epoxy glue to the back of the frames.
2. Press Frames: Press the frames into place and hold them for a few minutes to ensure the adhesive sets.
3. Allow to Dry: Let the adhesive dry completely before moving on to ensure the frames are securely attached.

Install Rubber Legs:

• Select Leg Position: Determine the best positions for the rubber legs to ensure stability. Typically, legs are placed at the four corners of the bottom panel.
• Mark Holes: Mark the positions for the screw holes where the legs will be attached.
• Drill Holes: Drill small pilot holes at the marked positions to guide the screws.
• Attach Legs:

1. Position Legs: Place each rubber leg over its corresponding hole.
2. Insert Screws: Insert screws through the rubber legs and into the pilot holes.
3. Tighten Screws: Use a screwdriver to tighten the screws, securing the rubber legs firmly in place.

Prepare for Testing:

• Gather Testing Tools: Collect an incandescent bulb with a suitable socket, a USB cable, and an iPad for testing the USB charger.
• Set Up Testing Area: Ensure you have a safe and clear workspace to test the unit, with all necessary safety precautions in place.

Test Each Output with a Load:

• Connect Bulb to 12V Output:

1. Attach Wires: Connect the wires from the bulb socket to the 12V output terminals on the control panel.
2. Power On: Turn on the power supply and switch on the 12V output.
3. Observe Bulb: Ensure the incandescent bulb lights up and check for stable operation. The bulb’s high power consumption will provide a good test of the unit's capability to handle significant loads.
4. Measure Voltage: Use a multimeter to measure the voltage across the bulb to ensure it matches the expected 12V output.

• Repeat for Other Outputs:

1. 5V and 3.3V Outputs: Repeat the process for the 5V and 3.3V outputs, ensuring each output provides the correct voltage and the bulb lights up consistently.
2. Variable Output: Adjust the potentiometer to change the voltage and observe the bulb’s brightness variation, verifying the smooth adjustment and correct voltage levels.

Test the USB Charger:

• Connect iPad:

1. Plug in USB Cable: Insert the USB cable into the USB charger port on the power supply unit.
2. Connect iPad: Connect the other end of the USB cable to the iPad.
3. Observe Charging: Ensure the iPad begins charging, indicated by the charging icon on the screen.
4. Check Stability: Monitor the charging process for a few minutes to ensure it remains stable and the iPad charges without interruption.

• Measure USB Output:

1. Use Multimeter: Measure the voltage and current from the USB port using a multimeter to ensure it matches the specifications (typically 5V for standard USB charging).
2. Verify Readings: Confirm that the USB charger provides a steady and accurate output suitable for charging devices.

And here is the result!

Different Uses:

• Electronics Projects: Use the power supply to provide precise and adjustable power for your electronics projects, such as Arduino and Raspberry Pi setups, prototyping circuits, or powering breadboards.
• Testing Components: Test various electronic components, such as LEDs, motors, and sensors, by supplying different voltage levels and monitoring their behavior.
• Charging Devices: Use the USB charger to power and charge mobile devices like smartphones, tablets, and other USB-powered gadgets, ensuring they have a reliable and stable power source.
• Powering Tools: Provide power to small DC tools and devices, such as soldering irons, fans, and DC pumps, making your workspace more versatile.
• Educational Purposes: Use the power supply as a teaching tool for understanding electrical principles, experimenting with circuits, and demonstrating the effects of different voltages and currents.

Share Your Creation:

• Document and Share: Take photos and document the building process to share with others on DIY platforms, social media, or maker communities. Inspire others to build their own power supply units and showcase your innovative design.
• Provide Feedback: Share your experiences, insights, and any challenges you faced during the build. Offer tips and advice to help others who may want to embark on similar projects.

Maintain and Upgrade:

• Regular Maintenance: Periodically check the power supply unit for any signs of wear, loose connections, or dust accumulation. Perform regular maintenance to ensure it remains in optimal condition.
• Future Upgrades: Consider potential upgrades, such as adding more outputs, integrating additional features like overcurrent protection, or connecting to a computer for monitoring and control.

Now, I am curious:

What did you think of the DIY variable power supply project? Do you have any suggestions for improvements or additional features?

Have you ever built your own power supply unit? If so, what challenges did you face, and how did you overcome them?

How would you utilize a power supply like this in your projects? Are there any specific applications you have in mind?

What voltage levels do you frequently use in your projects, and how would this power supply meet those needs?