Posts with «calculator» label

Crippled Calculator Features Unlocked with Automated Help

[Aguilera Dario] likes his Casio fx-82ES calculator. However, it was missing a few functions, including complex numbers. A Casio fx-991ES has more functions but, of course, costs more. A quick Google revealed that if you press the right buttons, though, you can transform an fx-82ES into an fx-991ES.

Because it is apparently a buffer overflow exploit, the hack involves a lot of keys and once you cycle the power you have to do it again. [Aguilera] realized this would be a good candidate for automation and added a microcontroller to push his buttons. You can see a video of a breadboard version below. He also has a PCB version in the works that should be better integrated.

The automation hardware patches into the button matrix through test pads on the back of the calculator’s PCB. [Aguilera] soldered ribbon cable directly to these pads, then snaked it out through a slot cut into the back of the calculator case where it is terminated with a 0.1″ pin socket. An Arduino Mini is used in the prototype, the next revision will use an ATmega328P on a custom board. The uC interfaces with the button connections using the venerable 4066 chip which is able to act as an analog switch.

The board layout for the PCB version is shown on the project page. There is no word on whether this is meant to be a permanent addition to the calculator, or just plugged in for the exploit and stored away for use the next time power is cycled. Either way, it’s neat to learn about this exploit and a cool challenge to automate it!

If you don’t want to hack up an off-the-shelf calculator, grab some nixie tubes and make your own. Or, if you are short on tubes, try this one.


Filed under: Arduino Hacks

Fun Audio Waveform Generator Is More Than The Sum Of Its Parts

[Joekutz] wanted to re-build an audio-rate function generator project that he found over on Instructables. By itself, the project is very simple: it’s an 8-bit resistor-ladder DAC, a nice enclosure, and the rest is firmware.

[Joekutz] decided this wasn’t enough. He needed an LCD display, a speaker, and one-hertz precision. The LCD display alone is an insane hack. He reverse-engineers a calculator simply to use the display. But instead of mapping each key on the calculator and typing each number in directly, he only taps the four 1, +, =, and clear keys. He can then enter arbitrary numbers by typing in the right number of ones and adding them up. 345 = 111 + 111 + 111 + 11 + 1. In his video, embedded below, he describes this as a “rather stupid” idea. We think it’s hilarious.

The meat of the project is the Arduino-based waveform generator, though. In the second video below, [joekutz] walks through the firmware in detail. If you’d like a simple introduction to DDS, check it out (or read up our more in-depth version).

He also makes custom detents for his potentiometers so that he can enter precise numerical values. These consist of special knobs and spring-clips that work together to turn a normal pot into a rough 8-way (or whatever) switch. Very cool.

So even if you don’t need an R-2R DAC based waveform generator, go check this project out. There’s good ideas at every turn.



Filed under: Arduino Hacks

The Newest Graphing Calculator Game

Certainly everyone remembers passing time in a boring high school class playing games on a graphing calculator. Whether it was a Mario-esque game, Tetris, or BlockDude, there are plenty of games out there for pretty much all of the graphing calculators that exist. [Christopher], [Tim], and their colleagues from Cemetech took their calculator game a little bit farther than we did, and built something that’ll almost surely disrupt whatever class you’re attempting to pay attention in: They built a graphing calculator whac-a-mole game.

This game isn’t the standard whac-a-mole game, though, and it isn’t played on the calculator’s screen. Instead of phyiscal “moles” the game uses LEDs and light sensors enclosed in a box to emulate the function of the moles. In order to whack a mole, the player only needs to interrupt the light beam which can be done with any physical object. The team made extensive use of the ArTICL library which allows graphing calculators to interface with microcontrollers like the MSP432 that they used, and drove the whole thing with a classic TI-84.

This project is a fun way to show what can be done with a graphing calculator and embedded electronics, and it was a big hit at this past year’s World Maker Faire. Calculators are versatile in other ways as well. We’ve seen them built with open hardware and free software, And we’ve even seen them get their own Wi-Fi.


Filed under: handhelds hacks

High Cost Arduino Calculator Is Unwieldy, Still Cool Though

One of [Kale_3D]’s teachers had made an Arduino-powered calculator. It wasn’t robust and didn’t last too long in the classroom environment. After the non-functional calculator sat around the class for a while, [Kale_3D] decided he would give a shot at repairing it. Along the way the project didn’t just get repaired, it got a full rebuild.

This calculator uses a full 16 button matrix keypad. The Arduino deciphers button pushes with the help of the Keypad library, at which time the appropriate character is displayed on the 2×8 LCD screen. Selecting the function is a little different from normal since this project is limited to 16 buttons. Two of the buttons allow scrolling through not only standard arithmetic functions but trigonometric functions also. This was one of the features that the previous version was not capable of.

To protect the components, an enclosure was made out of 1/4″ laser cut wood. The pieces have notched edges to permit a nice fit. Even so, corner blocks were added to give the case even more rigidity.

Yes, this calculator is not practical, but that’s not the point. In the end [Kale_3D] felt that the project was definitely worth doing. He had learned a bunch of stuff about Arduino and especially code debugging! Most important of all he had a good time building it. There’s a video after the break showing how it works. The code and wiring diagrams are available for download on the project’s Instructable page.


Filed under: Arduino Hacks
Hack a Day 20 Jan 03:01

Mod turns your graphing calculator into a selfie camera

Your graphing calculator may not be getting much use these days now that other mobile devices can do the job, but it still has a few tricks up its sleeve if you're willing to do some tinkering. Christopher Mitchell's latest project, ArTICam, lets you turn a TI-83 Plus or TI-84 Plus calculator into a selfie-oriented camera. The mod mostly requires a Game Boy Camera and a programmable Arduino board like the Uno. After a little bit of wiring and some (thankfully ready-made) code, you can snap self-portraits with a calculator command. The 128 x 123 grayscale pictures you take won't win photography awards, but that's not the point -- this is more about having fun with gadgets that might otherwise sit in the closet gathering dust. Hit the source link if you have the gear and want to give ArTICam a whirl.

[Thanks, Christopher]

Filed under: Cameras, Handhelds, Nintendo

Comments

Source: Cemetech

ArTICam Interfaces Game Boy Camera with TI Calculators

[Christopher Mitchell] has given Texas Instruments calculators the ability to capture images through a Game Boy Camera with ArTICam. First introduced in 1998, The Game Boy Camera was one of the first low-cost digital cameras available to consumers. Since then it has found its way into quite a few projects, including this early Atmel AT90 based hack, and this Morse code transceiver.

TI calculators don’t include a Game Boy cartridge slot, so [Christopher] used an Arduino Uno to interface the two. He built upon the Arduino-TI Calculator Linking (ArTICL) Library  to create ArTICam. Getting the Arduino to talk with the Game Boy Camera’s M64282FP image sensor turned out to be easy, as there already are code examples available. The interface between the camera sensor and the Arduino is simple enough. 6 digital lines for an oddball serial interface, one analog sense line, power and ground. [Christopher] used a shield to solder everything up, but says you can easily get away with wiring directly the Arduino Uno’s I/O pins. The system is compatible with the TI-83 Plus and TI-84 Plus family of calculators. Grabbing an image is as simple as calling  GetCalc(Pic1) from your calculator program.

So, If you have an old calculator lying around, give it a try to enjoy some 128×123-pixel grayscale goodness!


Filed under: Arduino Hacks, classic hacks

Kit Review – Sinclair Cambridge Calculator

Introduction

It’s no secret that I enjoy kit reviews – it’s always interesting to see how well a kit goes together, along with the quality of parts, documentation and so on. But what about kits from the past? And not 2003. Recently a very rare opportunity to purchase a sealed Sinclair Radionics Cambridge calculator kit appeared on ebay – so it was ordered rapidly and duly delivered to the office. And thus the subject of this review.

You may be familiar with the Sinclair name – Sir Clive Sinclair introduced many innovative and interesting products to the UK and world markets in his own style. Some were a raging success, such as the ZX-series home computers – and some were not. However in 1973 Sinclair introduced a range of calculators, starting with the “Cambridge”. It’s a simple four-function calculator with an LED numeric display and a somewhat dodgy reputation.

The design evolved rapidly and at the Mark III stage it was sold assembled and as a kit. At the time handheld calculators were quite expensive, so the opportunity to save money and get one in kit form would have been quite appealing to the enthusiast – in January 1974 the kit retailed in the UK for 24.95 (+ VAT):

Assembly

Putting the Cambridge together required a balance of healthy paranoia, patience and woodworker mentality (measure twice – cut once). There wouldn’t be any second chances, or quick runs down to Altronics for a replacement part (well … there was one) so care needed to be taken. If you’re curious about the details, I’ve uploaded 82 full-resolution images from the build, including both instruction manuals and schematic onto flickr. Now to get started.

 The kit arrives in a neat, retail-orientated package:

… with the components on one side of the foam:

… and the other side held he assembly guide (underneath which was a very short length of solder and the carrying case):

At this point I was starting to have doubts, and thought it would be better off in storage. But what fun would that be? So out with the knife and the shrink-wrap was gone, revealing the smell of 1974 electronics. Next to whip out the instructions and get started:

They are incredibly detailed, and allow for two variations of enclosure and also offer tips on good construction – as well as the schematic, BOM and so on. Like any kit it’s wise to take stock of the components, which gave us the PCB:

… the passives, diodes and transistor – and some solder wick:

At this point it turned out the all but one of the resistors were anywhere near the specified values in the instructions, and I wasn’t going to trust those electrolytic capacitors after 39 years. The replacement parts were in stock – including the original 1n914 diode that was missing from the kit. Thanks Clive. There was also a coil of unknown value:

… and the ICs, which included the brains of the operation – a General Instrument Microelectronics CZL-550:

… and an ITT 7105N:

… a bag of battery clips, buttons and adhesive-backed foam (which deteriorated nicely):

At this point it was time to fire up the Hakko and start soldering, not before giving the PCB a good hit with the Servisol cleaner spray. I was worried about the tracks lifting while soldering due to heat and old-age, however the PCB held up quite well. The first step is to solder in the clips that hold (just) four AAA cells:

… then the resistors and diodes:

… followed by the transistor, ITT IC, ceramic capacitor and coil:

Uh-oh – that ceramic went in the wrong hole. One leg was soldered where the coil was to sit. Without wanting to damage the PCB, de-soldering it was a slow, slow process. Then of course I didn’t have a ) 3.3nF in stock, so a quick spin to Altronics solved that problem (I bought 50) – one of which finally went in:

The transistor was also a bit of a puzzle, I hadn’t seen that enclosure type and the manual wasn’t much help, so the semiconductor analyser tester solved that problem:

The next step was to fit the display, which is wedged in the large gap at the top of the PCB. The tracks on the PCB are supposed to meet the display, however time had affected the tracks on the display module, so I soldered small wire links across the gaps:

Following the display were the two (new) electrolytics:

And now to the main IC. There wasn’t any second chances with this, and after some very gently pin-bending it dropped in nicely:

After a short break it was time to assemble the keypad, which went smoothly. After cleaning all the foam dust off the buttons, they dropped in to their frame which in turn dropped into the enclosure, followed by the keypad layers:

You can also see in the display window and shroud have been fitted. From here the PCB is inserted:

… and a sticker from years gone by, as well as the metal clip over the bottom of the power switch. At this point a quick test with four AAA cells showed signs of life on the display, so the rear enclosure could be fitted:

Now for the battery and final cover, and it’s ready to go!

The digits are quite sharp, but very small – and set back from the window. This makes photography quite difficult. At the time if your calculator didn’t work, you could send it off to Sinclair and they’d repair or possibly replace it for you:

Using the Cambridge

Well it works, so you have a calculator which is genuinely useful. However the Cambridge has a few quirks, which are attributed to the basic functions of the main IC. For example, when entering numbers the screen is filled with leading zeros until you select a function, however by using the manual you can complete complex work including square roots, percentages, loan repayments and much more.

Furthermore the Cambridge is quite the silent achiever, you can work with numbers as small as 1x10E-20 and up to 9.9999999E79. You simply enter the numbers in decimal form (e.g. 0.000000000123) … even though the display won’t show all the digits, they’re being stored in a register. To then extract the result, you continually multiply or divide by ten (making note of how many times you do that) until the digits appear on the screen. It sounds nuts today – but in 1974 it would have been a cheap way of avoiding a more expensive calculator. In the following video you can see th Cambridge in action, plus the results of dividing by zero:

More about Sinclair

The following video is a BBC dramatisation of the rise of the home computer in the UK market, and the competition between Sir Clive Sinclair (Sinclair) and Adam Curry (Acorn Computers) – which is quite entertaining:

You can find out more about the history of Sir Clive Sinclair here, and the calculator range here. If anyone can connect us with a Science of Cambridge MK14 computer, contact us.

Conclusion

From a 1974 perspective, that would have been a great kit to make, with some love and care it would have been successful. By today’s standards it was quite average – however you can’t really judge it from a 2013 perspective. Nevertheless, kudos to Sir Clive Sinclair for his efforts in knocking out a useful product as a kit. If you’re a collector, and see a sealed unit on ebay or elsewhere, give it a whirl. Just take your time, “think before doing”, and replace as many of the components as possible. I’ve put all the images in full resolution up on flickr, so you can follow along in more detail.

And while you’re here – are you interested in Arduino? Check out my new book “Arduino Workshop” from No Starch Press.

In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

 

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