mini-makes: benchtop power supply

As a maker in the making, I have seen many videos of people testing their maker projects. What has always interested me are the videos featuring electrical circuits, such as LED projects. People were able to test their LEDs and programs very easily. I knew I wanted that ability as well. What I didn’t know I needed when my maker journey began was a benchtop power supply. A benchtop power supply provides you with power that can be adjusted to meet the needs of your project. So, instead of having to go out and purchasing a dedicated power supply with particular specifications to test your project, you can simply dial in those specifications into the benchtop power supply and off you go.

Initially, I looked into manufactured units from various companies. As usual, I looked at what was offered on Amazon and compared the various units based on their reviews. I came to realize that a reliable benchtop power supply was going to cost a decent amount of money. I didn’t need anything high end, but I wanted something reliable. I had my sights set on a KORAD unit that was highly reviewed and reasonably priced at about $130. But then I came across a video talking about this:

DPS3005 by RuiDeng

This is a DC to DC Power Supply module from a Chinese company called RuiDeng. The unit is specifically the DPS3005 with USB and BT communication, which provides output of up to 30 volts and 5 amps. It provides step-down conversion of constant voltage and current and features a detailed LCD screen. Best of all, this unit with the communication features (microUSB and Bluetooth) cost a mere $35 shipped. Of course, shipping it from China meant that it would take 5-6 weeks to get here and sure enough, it took the entire 6 weeks. What came in the box was the module itself and the two cards for microUSB and bluetooth communications. Only one of the two can be used at a time because there is only one connector on the module.

module and two communication boards (microUSB on the left, bluetooth on the right)
back of the module

the design

My plan was to reuse an old laptop power adapter and cannibalize the barrel connector from the laptop itself. I would install a switch for an extra layer of safety and use two banana posts as my positive and negative outputs. This would all go in a 3D printed case that I will quickly design in Fusion 360 and print with some silver PLA. So, off I went and before long, I had a model drawn up.

The first picture shows the front view. A large opening for the module to be inserted. It is sized so that the module will snap in place using its built in clips on either side. The two holes are for the banana posts and the case features a vented lid that will be secured with M2 screws at the corners. The second picture shows the back view, which highlights openings for the switch, the microUSB port, and the barrel connector for the laptop power supply to connect. I also added more vents to the back to improve airflow through the unit.

ready to assemble

With my model complete, I sent it to the printer and after about 7 hours of print time, the case was complete and had no issues. In retrospect, I probably could have increased the panel thickness to improve the structure of the case, but it wasn’t too bad. The next step was to wire everything up and give it a test run. I decided to install the bluetooth card as well, even though the microUSB card would be the one I would primarily use. It’s better than having to look for it when I wanted to use it. This way, I can simply open the lid and swap the connection.

I used red and black wires to keep things color coded and used black heat shrink to insulate the end connections. After everything was wired, I thought that maybe I had made the case a bit too large. However, the additional space will provide more airflow and add to the safety factor. I used 22 gauge wire for the connections and according to the American Wire Gauge Chart, it can handle up to 7 amps when used as chassis wiring, which is what I am doing here. This power supply module’s maximum output is 5 amps, so I should never come close to the wire’s maximum rating.

i got the power

All that was left was to plug it in and see the end result. I can’t tell you how satisfying it to go through the process of making this benchtop power supply. I will get a lot of use out of it as I have many projects in mind that will require circuit testing. This is a steal for just $35 or less. I’ve tested the output and voltage and current seem to be within a small margin of error. I’m very satisfied with this product and highly recommend it to anyone needing a budget friendly benchtop power supply. All you need is an old laptop power adapter and you’re pretty much 90% of the way there.

I have used this here and there and it works great. I have yet to take advantage of the memory features but considering I mainly do projects with 5V components, I don’t really have a need for it at the moment. For now, I look forward to using this to help me build more interesting projects in the future. Questions and comments are always welcome!

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