MiOYOOW Soldering Practice Kit, 6 Digits DIY Calculator Kit USB/Battery Powered Desk Calculator Soldering Project Kits for College High School Learning Electronics and Home Office Use

This went together very easily for me. Took a few relaxing hours, the kit had everything needed, and the assembly was straightforward. Finished product is a usable basic math calculator. For the price, I'd rate it as great value.The PCB is clearly labeled for all parts. It's so intuitive, I think you'd have to sort of deliberately try to put it together wrong. In fact, the case assembly was more difficult than the electronics assembly. Neither was very difficult.The kit includes the PCB, 17 keys (base, label, two-part clamshell pad), battery holder, micro-USB power jack, single capacitor, single IC with socket, and two 3-digit LED displays. If I counted right, that's 126 solder connections, all but two are through-hole. The component that uses two surface mount points also has two through-hole points. Then there are four board standoffs with nuts, four board mounting screws, and four case assembly screws with nuts. The case itself is four sides (each unique shape), and a top and bottom. The kit also comes with a CR2032 coin type battery, but the one in mine was dead. And a pre-printed, color, slip of paper that you can cut up to use as key labels.To assemble, I used a soldering iron and solder, wire cutters (only for the capacitor), and a tiny Phillips screwdriver with needle-nose pliers for case assembly. Oh, and scissors to cut the key-label papers to size.Once assembled, the unit appears to be quite durable. The keys press with definitive tactile clicks. I have not run through testing of the resistor color band function, but it does basic math functions correctly (+, -, *, /). The display is 6-digits provided by two 3-digit LEDs placed side by side. The displays are bright and easy to see. The chip does have a lo/hi error function that displays briefly on over/underflow, and then it shows the truncated result. One quibble on the case - and it's minor - the assembly screws stick out the back by a millimeter, so the completed unit won't be friendly to scratch-able surfaces.As a kit? Great! As a good desktop calculator? Well... there's always pride of assembly, right? And it's quite distinctive looking.

This was an easy to assemble project that was also entertaining. A beginner can likely do it with no instructions. ( ask me how I know, lol ) the best part, it works! And works very well.

Purchased as a gift for grand. He loves hands on projects.

Edit (04/29/25): I have bought three total units as of this edit and I have discovered a second function on the calculator which I will explain. You will notice that it comes with a color code for each button / number. The color code is actually for the resistance value "bands" (the colored lines on a resistor) for resistors and the extra function is for calculating said resistance values. In order to use said function you must press the "Mode" button and the display will read "r" showing you have entered into the resistance calculator function. New picture includes the color chart and a resistor for reference. You read the resistor as follows: Brown, Black, Red, and Gold. I have included a second image (not included with kit) with a breakdown of resistor color codes to help with understanding the second function.I will explain later in my review about the missing fifth star....This project was very quick and simple. The entire thing took about 30 minutes to solder and put into its case. Perfect size to fit in anyone's hand whether its a man, woman, or child and I say this because once I built it and tested it I gave it as a gift to a family member and they along with their child held it and used it.Honestly the most time consuming part was attaching the white button tops and the clear tops. Also the button mechanism itself (the part that is attached to the board and being pushed down) is very stiff / sturdy. These buttons take about as much pressure as a computer keyboard button in order to work.Now the reason for 4 instead of 5 stars.The calculator is battery powered or USB powered and it did come supplied with said battery, however a USB cord was not supplied (a "Micro USB" cord is needed). Also the buttons did not come with any labels to attach to them and or pre printed on them. Though I should point out that each button has been labeled on the board itself (small print) and the layout for each button (ex. location of numbers like 1 or 2 and equation symbols like = or X) is standard to a normal calculator layout.Overall I would rate this as 4.5 out of 5 only because a USB cord (again a "Micro USB") was not supplied and button labeling could be better.

Ad states that there is a paper instruction folder included in package. Parts layout paper was in packagewith scan for instruction manual. A scan of the paper only gave another copy of the on-line ad. Instructions are necessary for putting together the plastic case and spacers.I am a very experienced electronic kit builder, so I would have no problem with the circuit board. But I doneed more info to put together the case and spacer. This item will be returned!

Entry Level Project.Approximately 1 hr to complete.Nice easy project for a student or anyone getting into electronics and soldering. Calculator is handy in identifying the ohms value for resistors. Still recommend spot checking with a multimeter to make sure they are correct but definitely a fun, easy, and handy calculator to have for DIY soldering projects. Comes with a nice case too.Also, does regular math for +, -, /, and * with a 6-digit display screen.

So the actual parts and materials here are pretty good quality, but as others have said, the directions are abysmal. They provide a broken QR code (supposedly for advanced instructions,) and one bare-bones schematic. One soldered and assembled, the screen powered on, then off again and now it does not function at all. I’d love to be able to troubleshoot it by checking the directions, but now I’m left with a paperweight that taught me nothing.

This has been my favorite kit so far, really fun to build, plenty of soldering to do. A good couple hours and it’s useful too!