A variable DC power supply is really useful to keep on your desk for charging your phone, plugging in a raspberry pi or any other low voltage electronic devices. By using voltage regulators you can set just the amounts to output, whether you need 3.3, 5, 12 or any other amount. This is a really fun project that you can customize to your needs, varying the amount of plugs, set the voltage, choose the size etc... I used MDF for the build, however you could make a box out of anything really to house the electronics.

Step 1: The Design

So I started with making a sketch of the design. For this build I need to use two voltage regulators, I picked mine up online. I also need a switch, and then I'm going to add a series of outlets that you can plug male pigtails into. Here I'm just confirming the current draw of an LED I want to wire so that I can determine the size of the resistor I need.

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So this is kind of the design that I'm thinking. The rectangles in the middle is to show the screens on the voltage regulators, then we have outlets underneath, a switch and a light to signify the unit is on.

Step 2: The Materials

So I'm starting with cutting up the materials for the box itself, and I'm using 1/4 inch MDF.

The final dimensions of the box will measure 8 x 8 x 2 1/2 inches so just cutting up the pieces for that.

Let's dry fit it to make sure everything fits!

Step 3: The Front of the Box

Now let's start working on the front of the box. So first I'm getting the dimension of the plug, setting up a compass. So drawing a circle, then seeing how far I want the outlets apart, and 3/4 of an inch in between each center seems like a good distance. All in all I want eight outlets, so drawing those all out.

Sketching out the space for the switch and the position of the voltage regulators. Also measuring out where the screens are, and where the holes need to go for those on the board, as well as where the little button that changes the output on the screen is located. And there it is, all marked out.

Step 4: Drilling

So I'm starting with drilling out the holes for the outlets using the drill press and a 7/16 inch bit. I'm also drilling holes in the center for where the screens will display to remove some material. And then cleaning up those rectangles with some chisel work.

Also drilling holes for areas that I need to access on the voltage regulators, a hole where you can insert a screwdriver to change the output, and a spot with a button to push to change the display on the screen.

Then doing a little sanding, a little cleaning up with a chisel, and I'm ready to assemble the box together. So measuring out 1/8 of an inch around the top wher I'm going to drill holes to screw it in. Doing some countersinking here.

Step 5: Putting the Box Together

Now to put the box together, I'm starting with yellow glue around the edges, then I'm adding small amounts of hot glue on one piece at a time, because it stiffens up so quickly, and this basically acts as a clamp while the yellow glue dries. It works really well. And then simply screwing the top in place.

Step 6: Finishing the Box

I decided to paint this box white for some contrast, and I'm just using cheap basic white paint here. To paint the inside of those little holes I'm using a small brush. Then once the paint dried I put on two coats of waterbased polyurethane which is nice because it doesn't add a yellow tone and it dries quickly, and of course it adds some additional protection.

Step 7: The Electronics

So real quick, let's go over the electronics here. So I have 20 volt ac dc power supply, first there is a switch, and we have an LED light which I need a resistor for, then this is hooked up to a voltage regulator and that connects to several output plugs.

So soldering a 2600 ohm resistor on the LED light here, and fitting everything in the box. I drilled a hole on the backside too, to connect a plug in to power the whole unit. Then soldering everything together. A lot of people don't like soldering, but it's really easy and fun, plus as you make more projects you get more practice. Just putting the wires into the voltage regulators, putting in the plugs and doing a little more soldering. Hooking this is and making sure it works.

Step 8: Hooking Up the Electronics

So on the voltage regulators there is this potentiometer on top that you can control and change the output. I'm also going to use this small mechanical screw here and enter it through one of the holes I drilled. Then on the regulator there is this little button to change whether to show the voltage output or input on the screen and now when I put the unit up here the screw is right on the button so I can push it to change the screen.

Next I'm hot gluing some wooden dowels in the corners here, and this so I can glue those to the box to secure the board. Then I'm hot gluing the plugs in, the switch, as well as the dowels on the boards.

Step 9: Wires

Now I put together a couple of cords with pigtails on both sides to plug into the unit to power different things, however to protect the wires, I figured why not secure some mason line, which happens to be bright pink with some hot glue. And I'm just adding a little glue, spinning the cord around and so on.

Step 10: Testing It Out

So the device works really well. To alter the voltage output all I do is to insert a small screwdriver into the top hole and turn it to get just the amount I need. And if I want to see what the input is, then I just click the button with the mechanical screw I put in. Now it's ready to use - set it to whatever voltage you need, plug in your phone, your raspberry pi, charge up your bluetooth speaker and so on....

Step 11: Conclusion - Watch the Video!

For a much better point of view, make sure to check out the video including all the steps to build this cool power strip.

<p>What about amps ma?</p>
<p>Apologies for the second post, I couldnt find an edit button<br><br>I forgot to say those modules go from 10V/10A to 100V/100A and unlike the ones shown are designed to be panel mounted<br><br>I would also have used proper USB sockets for several of the outputs too being honest as that is invariably going to be a main use for such a project and it even says that in the description, so opting to use odd connecters at one end means having to make a plethora of leads unnecessarily where the standard ones supplied with a project would work fine with the right socket to plug it into<br><br>Additional odd sockets could still be added too leaving other uses still possible, or just as easily cut up an existing lead with a standard plug at the device end then put whatever you want on the other end or even opt for an inline plug and socket allowing one lead to have many varied adapters that can be used easily similar to some test leads which might also be useful for applying temporary power to a circuit<br><br><br>The idea is good, but it felt like it had then been rushed rather than taking some time to apply a more practical and universal approach to the output sockets mainly<br><br>But thats only my opinion obviously</p>
It looks like she used 2.1mm DC plugs. Those are pretty standard, at least in the USA. Id have probably put a usb plug or two on it as well but you have to regulate those to 5v. You break lots of rules putting an adjustable voltage on a usb port (its begging for dead equipment).<br><br>I personally have tons of leads and pigtails with 2.1mm DC style connectors on them so her setup makes sense to me.<br><br>The problem with any diy bench supply is almost none of them have current limiting. The current limited adjustable supply I have is probably the best piece of bench equipment ive bought. Not as flashy as the oscilloscope but gets FAR more use. The lives of countless LEDs and components have been saved thanks to that unit.
<p>I have worked with wood for decades and that tip of using a hot glue gun as a &quot;clamp&quot; while the wood glue dries, is the best thing I have heard in decades and I am sure will save me a ton of headaches in the future.</p><p>For me, THAT was the best tip of the whole project and for me in particular because I often make a scale model of the projects I am making and this will speed up thing immensely. Now rather than waiting half an hour for each piece to dry I can just get on with the project. I can see me cutting out days of waiting with this tip.</p><p> Thanks for this :)</p>
<p>i want to be able to charge 12 to 24 volt batteries with it also</p>
<p>What about airflow? You want to use it just for few minutes? Better use heat shrink in case black tape boil inside box. Good idea after all.</p>
<p>Lo haces parecer muy simple. gracias por tu buen trabajo y sin duda una gran herramienta </p>
<p>Rather than replacing the trimmers with pots I would have just added addittional regulators like the 78 series to drop the existing voltages down<br><br>I dont really see the advantage of having variable voltages on something with a specific use, it would make more sense to knock up a simple regulated power supply for each voltage rail then perhaps using a 12v adapter of the highest voltage needed as the main power supply<br><br>This removes the need completely for regulating that particular rail entirely requiring only the lower ones to have their own DC-DC circuit<br><br>The same pre built module can still do the voltage, or there are some out there which show both the voltage and current from another source which could be used for each supply<br><br>Heres the first one that popped up on ebay<br></p><p><a href="http://www.ebay.co.uk/itm/Brand-New-Dual-LED-Digital-Voltage-Current-Display-Voltmeter-Ammeter-Panel-Gauge-/321520574652?var=&hash=item4adc1ea0bc:m:mXGj4IUSm7gR215admPyzkg" rel="nofollow">http://www.ebay.co.uk/itm/Brand-New-Dual-LED-Digital-Voltage-Current-Display-Voltmeter-Ammeter-Panel-Gauge-/321520574652?var=&amp;hash=item4adc1ea0bc:m:mXGj4IUSm7gR215admPyzkg</a></p><p>Thats the kind of thing I was planning to use myself for a similar project later in the year and which I think is far more versatile<br></p>
<p>I need some help. What I'm looking for is a DC regulator that regulates both the voltage and amperage? Something I could build....not sure where to start, but like the idea you created as a starting point. </p>
<p>So something that provides constant current and a maximum voltage, and will never exceed either the maximum current or voltage?</p><p>I think you're looking for something like <a href="http://www.ebay.co.uk/itm/5A-Constant-Current-Voltage-Voltmeter-LED-Driver-Battery-Charging-Ammeter-Module-/171396563942" rel="nofollow">this?</a></p>
<p>Its really great.Nice project to charge daily usage DC instruments and batteries.</p>
<p>I would suggest replacing the trim pots on the regulators with some panel mount pots. Trim pots will wear out pretty quickly when constantly adjusted. Keep the wires as short as possible though, since the pot is in the feedback loop of the switch mode regulator.</p>
<p>Good I-ble, </p><p>I have a couple suggestions. </p><p>1. These boards are designed to be mounted with standoffs which are available from most hobby places. A long screw goes through the standoff or you can use threaded ones or clips. either way, it makes the boards removable for troubleshooting or replacement and would most likely be stronger than just glueing. </p><p><a href="http://tinyurl.com/hfc3fzl" rel="nofollow">http://tinyurl.com/hfc3fzl</a></p><p><a href="http://tinyurl.com/jdz5pto" rel="nofollow">http://tinyurl.com/jdz5pto</a></p><p>2. Consider making the faceplate from an polycarbonate or aluminum sheet, it will last longer and be easier to mount items to as well as looking better.</p><p>Home depot has 6 x18&quot; sheets for around $4.00 - that's roughly enough for 6 faceplates. [28 ga.] or 24 X 36 in thinwall opaque for about 8.50 which would make roughly 48 faceplates at 3&quot; x 6&quot; each.</p><p>3. Use heat-shrink tubing to protect your wires. you can double them up for strain relief at the connector.</p><p>And yes, I will be looking into making this. </p>
<p>Your linx (besides the first one) are all the same, showing the pigtail connectors.</p>
Nice work.

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Bio: Hi I'm Linn and on my Youtube Channel I have lots of great videos about building, construction and fun projects. You can also check ... More »
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