And even though its perfboard construction, with all the hot glue snot, does not look very appealing. I would nowadays still say that such a project is pretty handy to have around., Because by simply putting it in series to your power source and load, you can see exactly what voltage and current it demands and thus what power and energy it requires over time.. This gets especially interesting if you want to determine, for example, how much powerenergy your custom project needs, how much energy it takes to fill up your brand new powerbank or if you want to see what you solar panel, is capable of.. The only problem with my power meter is that overtime. I noticed that there is actually a bug in the code that deforms the calculated energy. And nowadays there also exist commercial solutions that can do a bit less, but still enough for most people.. So building my exact project does not make that much sense anymore, but luckily a viewer of mine created a remake of the project which comes with tons of improvements.. So in this video I will try to build his project test it out and ultimately score it on a scale from 1 to 10. To let you know if you should consider building it as well. Lets get started. This video is sponsored by JLCPCB who produced the PCBs for this project which, like always, were flawless regarding their quality., And now they can even do upto 20 layer design for still an unbeatable price.

. If you are interested, then upload your Gerber files today to order your professional PCBs. Now first off. Let me tell you that all the files for this project are available on Hackaday, and that is where I also downloaded not only the code but also the EasyEDA files., To use them. I obviously had to sign into EasyEDA and then opened them as a schematic and as a PCB design., And just like that, with very little effort, we got our finished schematic and PCB which at this point we could customize if we want to.. But since I was not interested in that, I instead firstly had a closer look at the schematic to see what changed. The heart of the system is, this time, an ESP32 C3 which looks like this and is a big step up from the Arduino Pro Mini. I used before. Basically put it is fast, comes with more storage and way more features, including WiFi, Bluetooth and even an integrated Real Time. Clock.. Another cool feature comes to mind when comparing it to ESP8266 or ESP32 development boards that I used before.. Those boards always come with a small USB to Serial Converter so that your computer and microcontroller can talk to one another, which also means it is mandatory for programming the microcontroller.. This new ESP32 C3, apparently, though, does not need such a converter and instead can directly connect to a USB C Ports. Data pins, like shown here very handy and saves us money.

. The only thing I didnt like about this microcontroller was its package with the pins only accessible from the bottom, but more about that later. And in case you were wondering what these 5.1kohm resistors are doing at the CC1 and CC2 pins of the USB C port. Then. Firstly, let me show you what happens when not using them., As you can see, when using a normal USB A to USB C cable, then we get our desired 5V power from which can also draw quite a bit of current., But when using a USB C to Usb C cable, then we get absolutely no voltage at the USB port.. So the two small resistors are required for the power supply to know that it is supposed to output 5V and, as you can see, they seem to do their job perfectly fine.. But moving on to the second big change, which is this INA3221 IC, which is a Triple Channel Measuring IC. In comparison to my old design that utilized the INA219, this new one can basically measure 3 current paths, while my old one could only do one. And when Saying current path, I of course mean measuring a voltage drop across a defined current shunt, which then allows us to calculate the flowing current, the power and also the energy.. And if you are thinking to yourself, What is the point of measuring more than one power source and load, then let me tell you that there are certainly situations for that, which is why I build my old design twice over the years.

. Ok now to end the schematic part, let me just say that all required decoupling and filter capacitors were in place. I love that he included a USB A and USB C port for one input channel. We got a Micro SD Card port for logging like before. We got a bigger TFT LCD, which I really like, and even a full blown LiPo battery support with charging IC protection, ICs and voltage divider for monitoring and, of course, also a voltage regulator to get fitting 3.3V to power everything.. So yeah after closer inspection. I spotted no problems on neither the schematic nor the PCB side of things, which is why next I ordered my PCBs through JLCPCB, along with a stencil for later spreading the solder paste for a fantastic price.. And while doing that, I also shopped on LCSC to get all of the required components and after a week of waiting, everything arrived at my place and it was time for the assembly. To do that. I simply positioned the stencil on top of a PCB and spread the solder paste all over and through its fine holes.. Then all I had to do was placing all of the SMD components onto the correct spots on the PCB and to help you with that. I would recommend checking out the BOM file for the PCB and you can also search for specific components on it. By the way I am assembling two PCBs here just in case one doesnt want to work, and in hindsight that was definitely the right move.

, Because as Soon, as all the SMD components were in place, it was time to reflow the PCBs, and that is where problems for me started, because the PCBs were too big for my hot plate., But after heating, up both sides of the PCBs and doing some additional reflow work With my hot air gun and soldering iron, it was time for the easy part, and that was inserting all THT components and soldering them in place.. So after 3 hours of work, the end result didnt, look half bad, but before programming the boards. I firstly had to update my ESP32 boards library so that it does include the ESP32 C3 and I also had to install all the libraries, the code of Ovidiu utilizes.. But after that, I was happy to find out that the code for the first board uploaded without a problem.. On the other hand, though, the second board was not recognized by the computer, and that is where the package of the ESP32 C3 comes into play, because you cannot see whether the soldering process worked out fine.. So I did a bit more of reflow soldering and eventually even replaced the microcontroller, but no matter what I did, this board didnt feel like working with me.. That is why I was very happy that I made two boards, because the second one functioned without a problem. So let me begin telling you the positive aspects of this project. Navigating through the User Interface is pretty intuitive, even though not all button presses get always recognized.

. The measurement functions. All worked perfectly fine came with good accuracy, and the USB Ports for measuring did also work. And, needless to say, the energy calculating bug does not exist in this project.. I also really like that the battery voltage is visible at all times and, of course, the battery charging and protection does all work, just fine as well.. Last but not least, the SD card logging functioned without any problems, and I liked the way he made his code because it is really easy to browse through and understand. Unlike some of the code I published before., The only thing missing for me at this point was an efficiency mode that basically uses one channel for the input, power and another for the output power, and thus we can calculate the efficiency of, for example, a buck converter.. I tried implementing this feature by myself, but I kind of ran out of time and thus only got it halfway implemented. So I would love to see this happen in the future., And the only real negative aspect of this board is that, despite looking like, it could work with only a USB input. You should always power it with a battery.. I mean it does work with only USB power, but then you will have to endure this noise, all the time.. The reason for that is the TP4056 battery charging IC, which, without a battery on its output, still creates the 4.2V to power everything. But it also creates a hear able oscillation while doing so.

, And the last thing for me, which is a tiny bit negative, is that some ICs and, like I already said, the ESP32 – is kind of hard to properly solder. So I would not recommend this project to an absolute beginner., But other than that. Overall, I really enjoyed the project and that is why I am giving it an 8 out of 10 and I am looking forward to using it in other videos.. If you are interested in building one yourself, then here are all the main information and of course you can find more in the video description. With that begin said, I hope you enjoyed this video and if you did then dont forget to like share subscribe and hit The notification bell.

https://www.youtube.com/watch?v=suOimZ4gmQg