Wow, that looks pretty sweet! I think if I was modifying my TI-89, I would put in a better battery system such as lithium. Then when I grab my calculator after months of no use, it will still be ready for me.

I wonder how hard it is to read, in person, the text above the buttons?

Awesome. Now I wish I could do this with my own 89, especially since it flew across the room (but survived except a broken battery door…)

So does that make it a TI-89 Aluminum?

If he would have only known…
Anodizing is fairly cheap and would have increased the cool factor a bit. But another really nice thing about anodizing is that laser etching after it comes out white and crisp, and often it is pretty cheap too at the right place. So the lettering on the case could have been really slick-looking and easier to read (more contrast).
Maybe on case v2.0

Wow. Industrial Engineers actually do stuff?

Excessive! But cool! Astounding thickness of material in the walls. I reckon that’s literally bomb-proof now. But he deleted the stylish taper and roundy edge to the base.

oh not to mention if he intends this to be indestructible he get get it hard anodized and it would hold up much much better to impacts and scrapes

I’ve got a TI-85 that I use as my calculator (when opening Windows calculator or reaching for my iPod is too much effort). I’m pretty sure it’s about as indestructible as the IBM Model M keyboard.

Fun project, looks nice.
But I can’t believe an Industrial Engineer did more than the CAD drawings. He probably hired one of us Mechanical Engineers to do the actual manufacturing!

I also refuse to belove that the original casing actually broke. Back in high school we had to climb lots of stone stairs to reach our math lessons. We regularly dropped our TIs from a floor or two into the stone floor but none of them ever broke. Not even the battery cover.

I don’t see how a TI calculator is worth this, but eh, I guess he really likes his calculator? I have a pile of 85′s, 86′s, 89′s, and 89 titaniums that I’ve accrued over the years, they don’t really seem to be worth much…?

All you guys making fun of Industrial Engineers, I suppose you learned all your relevant skills in EE/ME courses? No? Amazing, you picked them up by tinkering and learning on your own, just like the rest of us.

Modern engineering degrees have nothing to do with practical skills, I know plenty of MEs who would have freaked out at “OMG circuit boards!” and plenty of EEs who could do the maths but would be baffled by the engraving process.

Of all the engineering degrees, who is expected to know a little bit of every single discipline? Oh yeah, industrial engineers…

Hey Guys… I’m Howard (the geek that built that calculator) Thanks for the comments.

Jeremy- Thought of rechargeable batteries, but I think a set of AAA’s last for almost half a year, so I don’t think it was necessary. The text on the buttons are easier to read than how it seems in the picture. however, having them color-coded would be better since I would know which secondary functions correspond to the diamond key and which secondary functions corresponded to the 2nd key. However, I’ve used the TI-89 long enough that it doesn’t really matter.

Reno- Thought about it, but Titanium costs significantly more than Aluminum.

SteveO- You’re probably right… I have a Bachelors Degree in Mechanical Engineering.

Aaryn- Yes it does! I have the file all set up so it says TI-89 Aluminum, but it doesn’t not fit on the bezel, which is quite ashame.

Vinito- Yes, I thought about it. But there comes a time when the new school year is about to begin, and I just want to finish my summer project. Not to mention its going to get scratched up anyways.

Brennan- One of the best machinists I’ve met actually has a degree in Industrial Engineering, believe it or not!

Nes- Yes, the stylish taper was deleted, which is a shame. This was done for ease of machining.

Kyle- Yes, I do have access to a machine shop (Haas Mini Mill), and though I have made many parts before, this is my first serious machining project, and learned a lot doing it. There were 3 versions machined from plastic before I machined the aluminum version. Total machining time for the final piece was around 10 hours. Total time time spent on the project? probably around 60 hours.

Mechanical Engineer- I dropped my TI-89 on numerous occasions, and what finally happened was a little piece of plastic that was part of the battery compartment snapped (see the 1st picture), so the calculator was fine, but wasn’t getting any power.

Jake- I needed a TI-89 pretty bad, so I ended up buying another one, but needed a summer project that would get me more machining knowledge.

with enough use, finger munge will fill the lettering, also from TI-89 titanium to aluminum.

IE FTW!!

@stevO: wtf? I’m in my first year of industrial sciences and I can mill.. *-) it’s not like it’s rocket science. I don’t say I can do it as clean as [Howard C.] but still. I studied Industrial sciences in secondary school to and believe me, I did learn how to mill.

To SteveO: Play nice with the other disciplines. You never know when you might end up with an IE as a manager…

Howard, that’s overkill to the point of elegance – a great little project!

Next summer, you could refine it further by milling the body from brass and making a set of replacement keys in black hard-anodised aluminium for a little bit of steam-punk goodness… I’m sure Jake would happily donate a few of his spare calculators to rob for the internals if you made a batch up.

@Howard.

Gotcha. Sooo…. Do you wanna buy a few more TI calculators? ;)

Is anyone marketing this!?

So…where’s the lid?

Hey Howard, Can you publish your solid model files for us/me? I’ve been meaning to make my own custom TI-89 Titanium case for awhile and having the key patterns would help me out… pplleeeaaassssse? :)

I’ll even try making the case on a Mendel :) Though I’ll probably still CNC mill it out of stainless in the end. My intention is not to make it indestructible, instead I wish to make it MUCH slimmer by using LiPoly batteries. (I can deal with the self discharge)

Appreciated the many comments.
James- Yes, it is on the blocky (and heavy) side. There will forever be this tradeoff between manufacturability and design elegance. Unfortunately, this being a machining project, the design elegance took a back seat. There’s always revision two.

Jake- How much? do they work?

lwatcdr- I doubt it. I could possibly make a mold from the original case and cast that instead. Also casting doesn’t leave a really nice finish. A lot of work has to be done after the casting to make it look nice.

Jackman- no, no one is marketing this. At the moment, it the business does not seem profitable. The machining time was around 10 hours, and even if it could be cut down to 2 hours of machining time, the cost of the case would still exceed the cost of a new TI-89.

Drew- Appreciated the comment. I would tend to disagree with you. This calculator has been with me for more than a good four years, and has taken many spills, including some onto concrete sidewalks. I would, without a doubt, say that TI calculators are extremely well-built. This fall was the straw that broke the camel’s back. And even after this fall, it was the plastic that chipped, the electronics were perfectly in tact.

D- Didn’t make the lid. Never thought of a clever way of making it. Its kept in a sock for the time being. To tell you the truth, the days of this calculator living in my backpack are over. Its living on my desk as a testament on what happens when a geek has way too much time on his hands.

qwertyphile- the mendel is not going to offer the precision to make this case. I have to resort to using a 1/16 inch endmill to cut the button holes.

I don’t get the $50 figure at all. The metal probably only costs $5. If someone asked me to do the machining, I would probably be insulted by a $50 offer, and it’s certainly not a favor I would just give to anyone. CAD/CAM work is expensive too.

It looks like a classic Game Boy.

bob: gold would be fine as long as you don’t mind carrying around a 5 pound calculator!

My HP-32S has taken a beating over the past 19 years—including a few falls to concrete from about a yard. Still kickin’! :D

Not that I like apple but should be titled “If Apple made a calculator” Of course it would be 1.5 times the cost and 75% of the computational power of the equivalent Calc. But it’d be cool cause it has an apple logo…..

I for one will never understand the popularity of TI calculators. They seem so limited and clumsy compared to HP’s offerings. Maybe they just marketed to schools/kids better, but it’s a shame since in the “real world” (that period of your life coming after school) HP dominates from all that I have seen.

This makes me want to buy more tools.

SWEET! A TI-89 Aluminum!

Sweet! I wish I could get a case like this myself! Granted, I normally do not use my Ti89, we tend to use a Citizen SR-270X as that’s what’s normally allowed at exams. Even so, I’d love such a case, and while I’m proficient with the tools we’ve gotten to use related to my study you can’t really use FIBs or epitaxial methods to make anything of this size.

Regardless, any chance you’ll sell some of these cases? If the price is right I’ll get one :-) My Ti89 has fallen on the floor once, and is chipped.