EEVblog #130 - The uCalc Credit Card Scientific Calculator / Computer

[dylanpalmediy]

I want one.

[Kilohercas]

where are you getting pcb and at what price, that looks so good :(

[samgab]

Wow, Dave, I am very impressed with this!

[mantaz111]

What chip do you using for tilt sensor?

[gwagenknecht10]

Micro SD, Sweet!

[TheOneToxic]

that is insane

Dave, i have never seen something so sexy as that uCalc. It is beautifully designed, just....i cant describe it.

Well done!!!!!!

[ekriirke]

I remember having a creditcard calculator 15 years ago, not exactly programmable beyond some contact infos, not scientific - about as thick as a CR2032

[SarahC2]

Dave is cute! ^-^

[effee1000]

DAVE: Is this on the market, can anyone buy one? I'm partial to my HP-50g but it's kind of cute and, being so compact, might come in handy.

[EEVblog]

@effee1000 No, sorry, it's still just a prototype.

[effee1000]

How much ESD protection is that solder mask on the front going to afford? I live where it gets extremely dry part of the year and I can for see wiping the thing out by picking it up after striding across a carpet or such.

[milos1993milos]

i think i know one commercial model of similar calculator

[c436237]

Absolutely splendid Dave. Great creativity.

[fax8]

David, you didn't say anything about the accelerometer you are putting there.. any info on it? I'm into motion sensing, check out my channel for more info.

[EEVblog]

@fax8 Just a bog standard 3 axis low-g accelerometer available from a dozen vendors.

[pedomohd]

can you manufacture this uCalc so that we can buy it from you Dave?

[heroineworshipper]

When do we get a blog about capacitive touch sensing? Those things never work.

[linagee]

I just had an idea. World's smallest wireless communication device. Put a QWERTY keypad on there, use a CC430 (TI MSP430 + CC1101/wireless) chip, surface mount antenna, and you're set. Make up two of them and send your friends a message.

[paulsdneym]

you shud do a commercial..

[kiyotewolf]

Ha ha ha.. I'd love to see a flavor of BASIC for this.. :D I'd so buy one of these if I could use BASIC with it. I'd buy one anyways.

[kiyotewolf]

<.< I'd put a tiny piezo in it too

[kiyotewolf]

are you going to make the back cover using something like the 3D printer?

[kiyotewolf]

could you make that thing include a RFID reader?

[feki00]

Great stuff!

I am the only one who is missing a serial port contact?

I think it would be a great addition.

Cheers!

[grantandcorky]

Great video, you got to give us an update when the project is done :)

[eddy66t6]

Hello,

Pardon me, but what do you mean by floodfill?

[EEVblog]

@eddy66t6 A solid plane of copper. Often known as a copper "pour"

[kasm279]

This sounds great but using superglue to hold it together and having no battery doors sounds like a terrible idea to me...

[jonhdoe1395]

Dave I don't know if someone asked you already, but what pcb cad software do you use in the end of the video? Thanks

[EEVblog]

@jonhdoe1395 Altium Designer

[ResidentHooligan]

EE vs. CS? I don't agree with Dave's assessment.

The key is staying relevant and ahead of the curve in your field whatever it is. I have seen talented EEs laid off for months before finding work again. I've gotten lucky and never been in this position, partly due to staying up to date. If the demand exceeds the supply, you'll have no trouble finding work. My personal advice is to do whatever you want and stay relevant.

- a software guy

[mrsteve1968]

Davie's a good ole bloke out of Tazzie, good ole mate he is

[Desmaad]

It's a bit like those Casio pocket computers from the 80's.

[neftalydotcom]

Looks great. I would solder a little spring to the upper board which contacts a pad on the back board in order to connect power, and would rout a short line in the backboard battery contact in order to facilitate sliding the coin cells out with a paperclip.

[AngryJoeMan]

What firmware will it be running?? you writing your own calc software? or is there some good open source code out there you can use? if you sold this as a kit, im sure loads of us would buy it! :)

[seeindarkness]

Nice project, I just wanted to mention that there a Fossil WristPDA that runs Chess or any other Palm Apps (up to os 4.2).

But this is great.

[kasm279]

@seeindarkness Palm OS ftw!

[MSCompuServ]

RoHs compliant sticker.

[madchef]

Companies don't "struggle" to make products like this, they "struggle" to make ones they can make a profit on. What are the COGS for this? They must be insane.

[Nickafyit]

Excellent Dave! Very informative. I like the idea of just sliding the batteries in. However, you will have to think of how you will change out the batteries later after your product is sandwiched all together. You might consider putting a small finger access hole on the back in order to be able to remove the used batteries. Also, you can allow the "Ucalc" to serve as a scrolling message board that can access some help files.

[555MONKEY]

Dude lay off the meth

[paijire]

im sure its been mentioned before, but im too busy to check all comments atm sry. but a smartphone is obviously a more programmable and powerful scientific calculator, and its already pocket-friendly by design as an added bonus.. also, i dont have time to watch thru the whole vid. right now if u mentioned phones. But i love the project, so prev. statement is actually more of a comment on how i like ur "because i can" attitude, not point out that u dont have to make one. keep up the good work!

[derverwirrer]

I would love one of those! I hope you get around to finishing it!

[0000mastermind]

that is so cool, hey dave i want one lol.

[frac]

For the battery - I've seen this trick: On that pad you added for the wire to the back board, solder a short compression spring instead. That spring makes contact with a suitably placed opposite pad once the boards are glued. Not sure of reliability, but ease of manufacturing is good. Even better, glue a bit of conductive rubber or foam rather than a spring.

[LauxHawk]

Wow very professional project. Are you putting it on the market?

[EEVblog]

@LauxHawk Maybe, if I could be bothered to finish it off.

[LauxHawk]

@EEVblog Nice. I love the black PCB. The traces on the front panel....do you worry about them getting damaged at all? The solder mask is sufficient?

[EEVblog]

@LauxHawk Solder mask is pretty durable. Only long term testing will prove it in any given application though.

[TheSagitis]

@EEVblog Dave I guess you should finish it and patent the product, or as a kit then sell it to Gary Johnson, you know Jaycar who monopolising Australia. Another way to help the store get some more electronic junks :)

[heroineworshipper]

Considered building one, but ended up writing an RPN calculator in C that can run on anything with a command line. Those battery contacts aren't going to work without some kind of spring loading.

[wateraarde]

Wonderfull stuff ! Don't you just love them electronics designers? Yeah!

[TerranOutpost]

Dave should change the name or at the very least the logo. The logo just kinda looks amateur, but the main problem is that the name is overused and theres too much google spam on it.

[valordk]

Great episode Dave! Thanks for sharing. When is the release, and what's the expected sell price? :)

[gbowne1]

Dave: Please do a EEVblog on something like "Tips for using ATMEL micros." or Tips for using PIC's", etc

[EEVblog]

@gbowne1 The proverbial "how long is a piece of string" might apply here! But yeah, I can probably do some stuff on that in the future.

[Norritt42]

@EEVblog Can you not make a AVR ->PIC and PIC -> AVR to unite the MCU hobby community ;). Seriously the step is big the first time if you haven't take the step yet. Like for me, I'm an AVR dude and want to go PIC. Where to start? OK PIC kit 2 but then. What is AVR freaks for PIC for exampel?... Great blogg!

[WhiteDawn]

I need to purchase this. Can't wait till it goes live!

[misskritt]

what a great idea! :)

x

[BenitoIsAwesomr]

Dave, I have to say your blogs have inspired me to possibly look into Electrical Engineering in college, I really have no idea what I want to do, but things like this are so awesome.

[AngryJoeMan]

i need one of those!! when will they hit the market??

[MrTranxistor]

love the design dave!

[FranklinLaserBlog]

Great Work! I like it!

[cr99991]

What prevents the batteries from falling out? How do you get them out intentionally to change them?

[EEVblog]

@cr99991 Friction between the top and bottom board. Can use a screwdriver, tweezers, or a good hard whack to get them out!

[RansomOfThulcandra]

@EEVblog @cr99991

If the batteries end up being too hard do remove, you could add slots on the back panel, starting just above the top of the battery areas, perhaps 1/4 of the battery diameter in length. That would allow you push the battery out with a paperclip or screwdriver far enough to grab it. Of course, you lose some rigidity of the contact, which may lead to other problems.

[rockchemistry]

@EEVblog For removing the battery design in a small narrow slot on the base PCB board so a toothpick or ball point pen can be used to push the coin cell out. No need to give it a hard whack.

[DanFrederiksen]

I can just imagine this guy Dave Jones getting all worked up about the battery mount when reviewing this product : )

squeeze based in a very flexible package. he wont like it : )

I think a thin rechargeable battery soldered in would be nicer. then you could maybe pot the entire backside in water clear casting poly urethane

[EEVblog]

@DanFrederiksen I just hate calculators you have to charge up. I like replaceable batteries.

[DanFrederiksen]

@EEVblog is connecting it to a usb cable for a few minutes really worse than going out to a shop and finding those overpriced little cells everytime it runs out..

or online with shipping and handling and TSA security fees : )

[hhdago]

Great project!

When you were talking about the center PCB, I thought about the chance of forgetting the opening for the batteries and the next moment you mentioned it.

Is there a power switch or does the controller switch off everything and goes to sleep when the calculator is not used and checks for activity periodically?

Oh, and how do CR2 and CR123 batteries fit into that scheme? ;)

[scancool]

that's really good soldering work!, did you solder the pic24 yourself or you put it in an oven?

[EEVblog]

@scancool Hand soldered.

[stridermt2k]

Dave...buddy. I think we can figure out how the batteries connect dude. No need to be exhaustive there.

In all seriousness this is a great project and it HAS been a privilege to see it in it's various design phases.

This is a great blog.

[EEVblog]

@stridermt2k Sorry. Many would say the whole design is obvious, so I've got to cater for the lowest common denominator. You'd be surprised at the questions I get.

[xspoonedx]

Hey Dave,

It's been interesting to follow this from earlier blogs (solar power and silicone bugs etc). I also admire your novel approach; bending the LCD pins was a stroke of genius, very impressive.

Also, what PCB editor is that? It looks like the same one from the old intro (with the spinning dev board you designed). I'm sure it's been asked before so maybe just a point in the right direction would be ace.

Also, a quick request for some more tutorials please :)

Thanks, and great vid as usual.

[EEVblog]

@xspoonedx It's Altium Designer.

[bejius]

@xspoonedx , It's Altium Designer

[jimipage6662]

( O.o) wow,I want one!

[souzzzzza]

Very nice calculator!

When do you start selling them?

[EEVblog]

@souzzzzza Given the slow progress of the project due to lack of enthusiasm, sometime in the 22nd century I suspect!

[Zed1967]

It would be nice to see a video showing us the calc in action and the maths you use when designing. I'm a bit crap at maths so an electronic maths lesson would be very welcome. :)

[EEVblog]

@Zed1967 The only math involved in this design is very basic, like estimating battery life.

[farhan260590]

I love the new intro to your videos!!!

[kraudio7]

so freakin' awesome PCB!!! I'm still making the most basic ones with all the copper showing xD

[TheRoknemec]

As always, it doesnt mater the video quality, Dave always impreses... If you think that you know a lot, he proves you wrong!

[thewii552]

why in the world is this in 240p?

[Rogy56]

@thewii552 Youtube hasn't proccesed the video yet

[EEVblog]

@thewii552 For the millionth time. It takes Youtube time to process the video. And there is a bug that automatically puts it live once it's finished uploading.

[thewii552]

@EEVblog sarry. never had that problem before. now i know never to ask.