KKmoon DIY Calculator Counter Kit with Acrylic Case LCD Display Multi-Purpose Electronic Calculator Counter Electronics Computing (1)

Whilst the quality of the components, the PCB and the case are first class the software that has been written shows some "schoolboy errors" and a lack of attention to detail.When you first power on the device yo get a 0,0 on the display. Select Mode to enter the resistance colour code calculator.Here you will see the initial C is missing from the display of the word Color. Press the up/down key to cycle through the options and the "C" appears. It looks like the initial screen clear routine is wrong.Also when using the Decimal to Hex calculator both sides of the indicator show HEX instead of 0DEC <=>OHEX. Similarly on the HEX to Decimal calculator it shows 0HEX <=>0HEX rather than 0HEX<=>0DECWhen you cut the key top legends cut slightly inside the line as they are very slightly oversize if you cut on the line.Construction of the board is easy the only difficult is bending the pins of the LCD header to match the profile of the sloped display. use teh side frame as a guide to do this.

I enjoyed making this kit but was disapointed to find that one of the two battery clips was missing from the otherwise nicely made kit. I agree that the case is a bit of a fiddle but not impossible to put together if you take your time. I found that one of the captive nuts next to the display backlight shorted out and caused the display to be quite dim. The solution was to use a piece of tape to insulate the LED leads where they wrap around the PCB. The calculator performs as described and will make a nice addition to the electronics club I help run at lunchtimes at the local grammar school. Easy to assemble the components onto the PCB and it makes a good kit to practice soldering on as most of the components are switches which are pretty resilient to poor techniques etc. FYI I'm a 60 year old electronics engineer who still loves making geeky gadgets for fun and educational use. Happy to recommend the kit and hope that yours has all the parts.

I am always chuffed when I get this out to do some sums. I had a blast putting it together, though be warned - the key legends are actually printed on the instructions and you need to cut them out with scissors, so don't crumple the instruction sheet! I had no problems soldering the components, though the case construction gave me some pause for thought - but I worked it all out eventually. Be careful with the display connector pins; the display has to be angled at around 30 degrees or so, so don't solder it parallel to the main board! You'll need a pair of CR2032 button cells, so be sure to buy these before starting the build.

This is the first kit like this I've built. In fact, it's the first time I've eve done any soldering. Was I too ambitious? No. It's actually pretty straightforward and I've watched the calculator being built a couple of times on YouTube so I knew what to expect. Once you've sorted out which resistor is which (I checked with my multimeter), the rest is fairly easy, especially if you download the pictorial instructions as the bit of paper you get isn't much use to a beginner.anyway, it took me a few hours, but it worked perfectly first time, so I'm pretty happy with the kit, and it looks good. The transparent bottom of the case lets you admire your soldering skills for years to come.So as a fun build kit, it's really good. As a calculator it leaves something to be desired. It can only handle 7 digits for instance. And only uses four decimal places. It's also a bit buggy. It does have th gadded features of telling you resistor values and converting numbers to HEX, but I doubt having assembled this calculator that you would ever really use it. Also, you'd have to do major dismantling to change the batteries and I don't want to take those captive miniature bolts out ever again!But that doesn't bother me too much since the fun of putting it together was the important thing.

Bought this just for a bit of fun to test out a new TS100 soldering iron I had bought.I have been into hobby electronics for over 20 years and have done a lot of soldering during that time so just got this kit because it was a lot of soldering to do that I could do in my sleep to give the TS100 a test drive.The kit was easy and fun to put together and everything was going well until I went to power the calculator on... the LCD backlight came on but nothing else worked. I triple checked all my joints with the aid of multimeter and they were all fine... I then tested the IC chip and it returned a fault on my reader / writer ... so thats where the fun ended.A shame as the calculator itself would have looked pretty cool and a lot of the features would have actually come in very handy for resistors etc.. oh well is having to be returned as faulty.I have built other KKmoon kits in the past and they have all been ok so maybe I just got a bad one..

It’s late on a Saturday evening and the Beast from the East is banging on my door, demanding to be let in. In desperation for something to make me forget the cold and miserable weather outside, I opened the package from Amazon containing my new DIY calculator and so unleashed 2 - 3 hours of joy ( yes, I lead a fairly sad life).The calculator was quickly and easily assembled - apart from a few fiddly bits of the casing - and when it was finished it looked lovely and worked well.The kit is an excellent project for anyone - a schoolchild with basic soldering skills and adult supervision could build it.Only issues are that you have to pretty much dismantle the entire case in order to change the batteries, it only calculates to 3 decimal places and that the calculator would have been more useful if the designers had programmed in a few more functions - perhaps additional science functions and a percentage key.Highly recommended.