Best project calculator 2020.
1 – DIY Calculator Counter Kit with Acrylic Case LCD Display Multi-Purpose Electronic Calculator Counter Electronics Computing
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Overall this is a descent kit. I didn’t have any issues with the directions (a URL on a printed piece of paper) or soldering the components on the board.My biggest issues with this:- The screen uses a rigid pin header, with instructions to bend the pins to just the right angle to make it fit perfectly in the socket and mount to the rest of the case. If you don’t get it right (which I wasn’t able to do), you’ll have major difficulty attaching the screen assembly to the rest of the case. This wouldn’t be so bad if not for my next issue.- To replace the batteries you need basically disassemble the whole case. This wouldn’t be so bad if the screen assembly was easier to attach/detach.- It only does 7 digits. No clue why. I expected it would be able to do at least 8 digits per operand, especially with what appears to be a 16×2 character display.Overall, for the price, it’s a good learning experience for folks who are learning how to solder through-hole components. As a complete product, the case assembly leaves something to be desired (with the battery replacement and screen attachment issues). As a calculator, only having 7 digits is just bad. .
I buy my brother some sort of electronics kit for Christmas every year, and decided that this year he would get this KKmoon DIY Calculator Counter Kit with Acrylic Case LCD Display. Because the price was so low (less than $15) I decided to order two of them and build one for myself.As a calculator, this is really just a four function (+, -, x, /) plus square root. It is floating point, and uses Algebraic Entry (AOS or ‘infix’) just as most non-engineering calculators do. The display is a two-line, back-lit blue LCD; the first line shows the math formula you entered, and the second line shows the answer after you have pressed the = key. *****Caveat this calculator can only be used for very basic math, because it supports only a maximum of 6 or 7 digit numbers .if you enter larger numbers (more digits), or the result of a calculation has too many digits, the calculator will give an error display. If you are just doing basic/simple math and don’t need to represent large numerical values, or values with lots of decimal positions, you will probably be OK. ******A single ON/CA key doubles as a ‘power on’ button and the ‘clear all’ button for the calculator. There is no ‘power off’ button, since the calculator turns itself off automatically if a button has not been pressed for a while.A ‘backspace’ key is provided; each press backs up and erases one more digit, allowing you to make corrections.The calculator runs from two CR2032 lithium ‘button’ cells, 3V each for a 6V total. These batteries (cells) are NOT included with the kit, so you will need to buy those separately as well. The calculator’s case must be partially dismantled to replace the batteries, but they should last for many hours before needing replacement. ******Note that three different pieces of documentation direct you to use three different kinds of battery. One of the recommended types must be a typo, as it is ‘unobtainium’. Another recommended type is clearly incorrect, since it calls out a much smaller part that will not fit the battery connectors. ONLY the third type, as specified on the main printed circuit board silkscreen lettering is correct .make sure you buy the CR2032 type and ignore everything else in the documentation.****The kit comes with a single sheet of paper, printed on one side only, which tries to be the assembly guide, the parts/circuit board layout, the electrical schematic, and instructions for use. It is barely up to the task, and a less experienced kit builder might have some issues understanding how it all goes together. All text is clearly printed, but in muddled Chinglish. There are really NO printed instructions regarding assembly of the case itself. However, in tiny print on these instructions is a URL to a webpage that includes a series of detailed photos that will lead the kit builder step by step through circuit board and case assembly; I recommend studying this webpage before starting to assemble the kit.The calculator runs based on a single microcontroller IC, which comes pre-programmed. It mounts to the main printed circuit board using a socket, which is good.The printed circuit board has provision for connecting an external power supply, instead of using the batteries, however the parts for this are not included with the kit, not is the case drilled to accommodate a power supply connector. For extended calculator use, I would suggest buying a ‘wall wart’ style power supply with a regulated 6V output at at least 300mA, and wiring it into the case and to the provided external power supply pads on the printed circuit board. You could optionally buy a compatible/suitable barrel connector to match the power supply and mount it to the rear of the case; your would need to drill a hole to fit the connector.Besides the basic math functions of this calculator, it has several other useful features:- It has a mode where it will calculate the requires resistor value for use as a current limiter for an LED; you enter the difference in voltage between your power supply and the LED’s forward voltage, then enter the LED’s nominal current, and the calculator tells you the required resistor value.- I has a mode where it will convert between decimal and hexadecimal numbering, in either direction of conversion. The keys normally used for are marked +, -, x, /, = and decimal point are also marked with the letters A ~ F for use in entering hexadecimal numbers.- It allows you to enter the colors of the rings on resistors (4 or 5 ring) and it will tell you the resistance and the tolerance in %. The numeric keys are marked with the resistor color band colors, and a few other keys are marked with the tolerance colors (e.g. silver, gold).With the above extra features, this calculator could be a good choice for a student who is learning electronics, or a home electronics hobbyist. If it also had a few more modes, perhaps for calculating Ohms law relationships and capacitive and inductive reactance, it would be a real winner in this regard, but unfortunately it stops with just the above mentioned features.The calculator consists of two printed circuit boards. One is un-assembled, and you must solder a handful of resistors, a single capacitor, an IC socket and a pin header, and the 20 tactile pushbutton switches. The pads are fairly large, and this circuit board has a nice solder mask and silk screen, so soldering is fairly entry-level and easy. The other circuit board is pre-assembled, and has the LCD display, its back light, and the LCD controller ICs. The only thing you need to do with the second circuit board is to solder on the pin header connector that mates with the main circuit board.The case is five laser-cut clear plexiglas sections (base & four sides) and two more laser-cut black plexiglas sections (LCD bezel and keyboard bezel). The various sections interlock with tabs and slots, and a small number of included screws/bolts, nuts and spacers are used to mount the circuit boards and secure the case sections together. The kit includes four clear rubbery adhesive-backed feet which you stick on the bottom of the case near the corners.Unlike many inexpensive kits that have keyboards or keypads, this kit has proper keys to press .you are NOT just pressing on the tops of the tactile switches themselves. For every one of the 20 pushbutton switches, the kit includes a set of key top and clear key cap. A sheets of color printed plastic/paper has all the key legend inlays, and you cut them out with a scissors. Place each cut out insert between a key top and key cap and squeeze them until they snap together. Then press the assembly onto the appropriate tactile switch. Repeat for the other 19 switches. The result is that the key action is good and the keys are very legible for easy use. The only issue I had with this is that the cut lines marked on the paper are slightly oversized, so you really need to cut slightly inside the cut lines, not ON t
he cut lines.Overall, this seems to be a well designed kit with good quality parts, a decently attractive look and feel, and practical utility. .
One of my guilty pleasures as a hardware engineer is buying and assembling these diy kits to perfection, modifying them to the most practical state, generally spending way too much time on them. Let’s talk about this little guy.First off, this is not for a beginner. I’d wager that 50% of these end up in a drawer or garbage can out of sheer difficulty and fragility. This was a very time consuming project just keeping things standard (their standards) and probably added an extra two hours getting it to my standards(well, well above what most individuals seek).First of all, the internal button cell power source design is a joke. I did away with that, and have an external power source using a common barrel size jack on the back. It’s important to realize that these units employ a single 5v LDO and they’re designed to work with a low voltage power source (low as in very close to the reg range unlike a linear supply IC), so if you do use an external supply like I did, keep it as close to 5.5-6v as possible. Much more and you’ll smoke the LDO IC with thermal dissipation, moreover a lack thereof. You can actually give it up to 20-something volts and it’ll handle it just fine technically speaking (part is 7550-1 if you want to look at datasheet). Don’t change the filter capacitor size or the LDO regulator will freak out. The unit does not require much current to run, but I am not going to willingly power something with lithium salt/Cobalt/disposable button cells ever unless it’s a keychain basically.Second, using 2mm hardware is a nightmare. Some extras are included, which is good since I pulled the threads out of two nuts like it was Sunday school.Third, use the online instruction picture guide. It doesn’t say to, but you should bend the pins on the base of the screen by about 40° maybe a touch less. It makes assembly much easier. I also did away with the processor IC socket for space.These little project kits are ways for me to spend an evening mindlessly droning on something. I easily spent a few good hours building this unit, with no mess and flush cut solder joints. After it was done, the features are limited but somewhat useful for a workbench calc. The design is. ok. There isn’t much space for anything extra, and you really have to be clever about it. .
works as advertised, Would probably take an amature a few hours, I knocked it out start to finish in 1-1/2 hours with a few distractions and without downloading the instructions. I used 2032 batteries and they work fine the instructions the amazon website cite other batteries but anything 3v with right diameter is fine.One thing, the paper instructions say if I multiply 5 x 6 I should get 25 I may have missed a step because it reads out 30 instead 😛 LOL .
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2 – Calculated Industries 8528 Metric Do-It-Yourself Calculator
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3 – Calculated Industries Quilter’s FabriCalc Quilt Design and Fabric Estimating Calculator
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This thing is awesome! I needed this gadget very badly recently at the quilt store and when I asked why they didn’t have one, they insisted it was too complicated to understand. I found that hard to believe and it couldn’t be any harder than attempting to figure out what I needed by hand (I’m seriously math challenged). So when it arrived, I was determined to figure it out and make it work for me. It came with a big book I didn’t read, an instructional DVD that I didn’t watch, and a little pocket-size instruction book that actually goes INSIDE the back of the calculator case. Very cool. I love that it has a hinged cover like a door to close over it which will prevent any purse dirt from getting into the keys. Anyway, without even so much as turning it on, I sat down with the pocket instruction book determined to master this supposedly impossible device.The biggest thing about this calculator at first glance, is not to get overwhelmed by all the buttons. It looks very intimidating, but as with most gadgets, it turns out you really only need to use a few of the buttons for most tasks. So in addition to the numbers buttons, you will mostly use the top row of red buttons (that you use from left to right in order) and the Yardage or Inch button. You will be amazed at how EASY this thing is! First of all, users need to understand that there are defaults built into the calculator. For those who don’t know the term default, it means “a given or assumed amountâ€. It assumes you have 40″ of usable fabric, you’re using 1/4″ seams, there is an additional 4″ of backing all around, and all binding strips are 2.5″ wide. That works for me. You can change these default amounts if you want in the preference settings. It displays in fractional amounts but can be set to decimal or metric. Here’s how I used it to get borders, backing, and binding for a panel:1. My panel was 23″ across so I put in 23 and pressed the Inch button (above the 8) and then the Top Width button (top row, left red button).2. My panel was 39.5″ long so I pressed 39.5, then the Inch button, and then Top Length (top row, 2nd red button).3. My border was 4″ all around so I pressed 4, the Inch button, and Border (top row, 3rd red button).4. I don’t have a Drop (4th red button) since it’s a wall hanging vs. a bed spread, so I skipped that button and I pressed the last button, Quilt Ydg, once.NOTE: Quilt Ydg acts kind of like a “total†button. Pressing it multiple times will cycle through all the totals I needed. On the first press, it told me my entire finished quilt top was 1-1/8 yards. I repeatedly pressed Quilt Ydg it told me I needed 1-5/8 yds for backing, 1/2 yd for the border, there would be 4 strips for the border, the border strips would be 4-1/2″ wide, I would need 1/3 yd for the binding, there would be 4 binding strips, and the strips would be 2 1/2″ wide.5. If I press the + sign after each yardage amount that is shown, it adds those amounts together and calculated a total amount of yardage needed – which worked for me since all of my borders, backing, binding strips would be of the same fabric.This has changed my math-challenged quilting journey! Obviously, with all those keys, it can do many more things up to and including telling you how much the fabric will cost. If I ever feel the need, I can pull out the handy-dandy pocket guide to work those numbers out, but I’ll probably be sticking to the basic calculations for now. I blogged it here: [ ] .
This is the single most greatest thing I’ve ever bought. There are YouTube videos that show you how crazy easy this is to use. No more wasting fabric, ever again. I’m a beginning quilter and can never really understand how many squares and stripes and pieces I need because the math gets out of hand. All you do is tell it how big you want your final quilt dimensions it will tell you how many strips, squares or whatever you need but more importantly it tells you how long and wide each single piece needs to be cut to make sure your quilt comes out right. Pure genius! Watch the videos and you’ll be back to buy this. Seriously. .
I bought this for Christmas for my mom who is an avid quilter. She has reported that it’s very useful and helpful to her in calculating her materials needs for her quilts. She has also shared it with her quilting club and they use it for group projects. My Mom isn’t particularly proficient with technology, but said the calculator is pretty easy to use and has good instructions. .
Hi:Just wanted to share how much I love my FabriCalc fabric calculator. It works really great! I find it most helpful when trying to figure out if the piece of fabric in my stash will be sufficient for parts of a quilt I am working on. It’s great when your designing your own quilt and you want to calculate how much fabric you need for each part of the pattern. This is Also a great tool to use when converting yards to metres. It gives you the equivalent with in seconds. It serves as a regular calculator too! Perfect when adding up your purchases before you reach the checkout. Comes with two excellent easy to understand instruction guides. One can be kept in your sewing room and the smaller one slides into a space at the back of the calculator itself, so that you have it with you at all times. I am so pleased with it. It makes a great addition to the many tools that are useful when quilting or sewing. An excellent Christmas, Birthday, or Thinking of You gift. I strongly recommend it. I LOVE IT!!!K. Jones. New Brunswick, Canada. .
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Best project calculator 2020.
Best project calculator 2020.