Casio Fx 115s Battery

I decided to share this log as this trusty computer 计算机 been with me for 20 years and I just threw it away today.

Casio Fx 115

Advanced scientific calculator features Natural Textbook Display technology to show your mathematical expressions exactly as they appear in the textbook. Protective hard case keeps the calculator from being damaged while traveling. Calculator is powered by solar power and features a battery backup supply. Calculator is designed to be the perfect choice for students learning trigonometry. Item 1 CASIO fx-115s VPAM Scientific Two Way Power Solar Calculator Flip Cover, Battery - CASIO fx-115s VPAM Scientific Two Way Power Solar Calculator Flip Cover, Battery $6.99 +$3.90 shipping. Solar & Battery Solar powered when light is sufficient, battery powered when light is insufficient. Plastic keys Designed and engineered for easy operation. (Super Visually Perfect Algebraic Method) All the features of the existing V.P.A.M. Series plus a new 2-line display and a useful Replay function. Casio fx-115ES Manuals Manuals and User Guides for Casio fx-115ES. We have 2 Casio fx-115ES manuals available for free PDF download: User Manual, Appendix.

I got myself a very new FX991. Well it is a 8 bit computer , with no ram no harddisk, with some register and with a display of 10+2 character.

What are the modification done to this machine ?

1) Overclock to 5X the speed. Tested with stopwatch, the slowest operation with this calculator is 110C52. The combinatorial function

Software engineering sommerville 10th. C(n,k) is defined as n!/[k!(n-k)!], where n! is the factorial function.

Normal calculator can take up to 20s to find the answer. On my HP 11C it took over a minute.

After overclocking it took about 2s in non turbo mode and within 1sec in turbo mode.

Casio Fx 115s Manual

2) added Rechargeable battery, these battery are charge using the solar panel allowing the calculator to be use without any light. I wounder why after so many years calculator still do not have this function. The rechargeable battery can last up to a week when new.

3) turbo, overvoltage overclocking. Crazy speed for bragging rights only.

Here I have a picture of the rechargeable battery switch. Have to on this to charge as well. The rechargeable battery is the one in blue above. They make the calculator FAT so that it would angle up for easy viewing , this open up the space available inside to add part required for this mod. Notice the wraping of plastic near the top, This is cause by overheating when I tried to charge the rechargeable directly under a lamp.

Here is the TURBO switch Beaumark rice cooker instruction manual.

Note the exam approval sticker at the back, The calculator with mod made it to A level, and all my U exam.

Casio Fx 115s Calculator

Next up is how overclocking and LCD contrast are adjusted, by changing the resistor on the RC (resistor capacitor circuit). Yes they do not have to invest in expensive crystal for clock control and it rely on an RC network, maybe they have a 555 inside. (555 is a clock control IC)

So after reading this article have you press 110C52 on your calculator to see just how long it take for it to calculate that. Got you!!!

Casio are one of the world's largest manufacturers of pocket calculators. The company was founded in Japan in 1946 (originally called Kashio Seisansho) and has its headquarters in Shibuya, Tokyo. As well as calculators, the company manufacturers a wide range of electronic equipment including electronic musical instruments, cameras and watches. The company was founded by engineer Tadao Kashio ('Casio' is an anglicized version of his name) who invented a cigarette pipe which became the company's first product. The compay then worked on other engineering product manufacturing until his brother Toshio suggested that they develop an electro-mechanical calculator. At the time electric calculators were essentially motorized versions of hand operated devices, but the new calculator was based instead on relay technology used in telephone exchanges. It was launched in 1954 and was the first to be manufatured in Japan. The company moved to electronic designs in 1965 with the launch of its first 'all-transistor' model, with integrated circuits taking over in the late 1960s, although electronic calculators were still large, expensive desktop devices. The first pocket calculators were the various versions of the Casio Mini, using six-digit vacuum fluorescent displays. Although they were just one of many calculator manufacturers in the 1970s, by the 1980s Casio was a technology leader launching the world's first graphing calculator, the Casio fx-7000G. Casio continue to be one of the largest calculator manufacturers, with their scientific models used widely in schools throughout the world.