Calc DBS

DigiTan · Posted: 27 Apr 2006 12:13:50 am Post subject:

Calc Dual Battery Switchover

This project is for anyone who's ever lost a Pgrm during a battery change; or gave up a high score because the screen was too dim. The fanbase for dead batteries and dimming graphics is a very small one, which made me happy to annouce the completion of project Calc DBS -- or Calc Dual Battery Switchover.

TI-82 during 5-hour Phoenix Marathon

This is a product-improvement on 2004's EED project. For those unfamiliar, it's a power management system that is attached to the calculator. Putting the "D" in "DBS" is the option to use AAA batteries, AA batteries, external power or any combination of the three. So whether you use regular batteries or rechargables, Calc DBS helps you save trouble and look good doing it. The original perks are still here:

Benefits:
* Indefinate gameplay
* Over x3 more time between battery replacements
* A screen that never flickers on keypresses
* Graphics that never blur
* Ability to power other hardware mods
* Built-in chick magnet

Improvements on the original

The original EED used automatic switching when external power was added or removed. This was done electromechanically with much success, however the switching allowed a 1/1000th second period in which the calculator would receive no power. That would cause your calc to reset if you forgot to turn it off when unplugging or inserting the cord.

Thanks to a new DMOS switch, Calc DBS switches over 52,000 times faster than EED. The new switch also allows a constant supply of power when it's between the "on" and "off" states, so there is no known chance of a reset. DBS also has a small amount of reserve energy, that has a number of direct advantages.

Any DC adapters between of 8 and 27 Volts will completely take the workload off your batteries. Lower adapter voltages of 3 to 8 Volts will assist the batteries and extend battery life by a slight amount. Otherwise, when there's no external power, your AAA and AA batteries will work together, giving you less screen flicker, high speed, and wickedly dark contrast.

Features & Interface

The status LED (shown in orange) indicates when external power is present, and it is now front-mounted instead of on the side. Next to that is a surge-protected DC adapater socket and a very tough 2.5mm linkport. The DC port can take power from wall adapters, cigarette lighters, car batteries, USB ports, a hampster wheel, it won't matter. Sources above 27 Volts are rejected automatically.

Summary & Upcoming

I'm working on a detailed guide and parts list for the system that will be published on my site, ticalc, and possibly UnitedTI. Calc DBS may also have a limited ability to recharge NiCad batteries. This has not been confirmed, but will be looked into.

elfprince13 · Posted: 27 Apr 2006 12:41:48 am Post subject:

/me drools.

leofox · Posted: 27 Apr 2006 08:36:55 am Post subject:

Wow thats awesome.. Not that i will ever be able to assemble such a thing..

Cant you send me one from Texas? Razz

DigiTan · Posted: 27 Apr 2006 04:20:47 pm Post subject:

Heh heh. I don't see why not. Cool

alexrudd · Posted: 27 Apr 2006 04:45:46 pm Post subject:

Seems like everyone is coming up with a great way to make money.

Sounds great, are there any pictures from different angles?

leofox · Posted: 28 Apr 2006 08:50:43 am Post subject:

DigiTan · Posted: 28 Apr 2006 05:06:26 pm Post subject:

Shhhh. You're ruining my sales pitch. :P

DigiTan · Posted: 21 Sep 2006 08:57:22 pm Post subject:

Still haven't gotten around to putting the schematic into CAD, but I did manage to find the original plan-on-paper diagram. Besides apologizing for the sidewaysness of the pic, I'll note R3 and R4 were re-calculated after the fact and I'll post those values this weekend.

For a design using so few parts, the performance is highly stable--and operated on the same breaker as industrial equipment this past summer with no problems. The only limitation is: any adapter voltage above 18 volts will require a heatsink on the regulator (marked "78L06").

In addition to this "universal" version, I'll post up a low-power version that can be powered via USB port and other small sources. More updates later.

todlangweilig · Advanced Member Joined: 14 Feb 2006 Posts: 470

Sweet, you finally got it done Smile

Can't wait to see what I can do with it.

Raster · Active Member Joined: 17 May 2004 Posts: 529

Nice DigiTan, once I get back home, I will probably build that for my calc :biggrin: .

AlienCC · Posted: 23 Sep 2006 01:52:09 am Post subject:

Digitan when I saw the title "Calc DBS" I was getting excited, thinking a relation Database for the TI. Then I saw this, while very cool, was nothing of that nature...how misleading. ;)

--AlienCC

DigiTan · Posted: 23 Sep 2006 05:45:28 pm Post subject:

I guess all the good acronyms are already taken. Very Happy

As a side note, I got all the parts in for the external memory function. It's probably not as big a deal now that msd8x is out, but I'll be doing a similar project anyway so; might as well. Mem size will be 64kB with the current hardware. Might also look into that Universal Translator idea from way way back.

elfprince13 · Posted: 23 Sep 2006 06:18:09 pm Post subject:

Digitan, has anyone told you that you are insanely cool recently? because they should. this awesome, keep at it.

DigiTan · Posted: 23 Sep 2006 08:50:14 pm Post subject:

Yeah last year I was fall-down broke. Thanks to a lot of hard summer work I can finally finance some stuff again (no more chasing $1's in the parking lot). That reminds me, I need to put in a UTI donation. Cool

elfprince13 · Posted: 24 Sep 2006 11:23:20 am Post subject:

DigiTan · Posted: 25 Sep 2006 03:11:16 pm Post subject:

Found out today it withstands having the power cord yanked from the wall -- even in an ASM prog. Bad for crashed ASM games, but good for everything else.

[edit]
R3 = 47k
R4 = 100k

DigiTan · Posted: 14 Apr 2007 09:34:26 pm Post subject:

Hooray for digital camera clearances! This pic of the Alpha-10 titlescreen was taken next to the transceiver at the university ham station. Also shown is my carrying case for the Calc DBS wall adapter (left).

Due to progress in an unrelated project. I *might* try to upgrade Calc DBS once more. Some options I'm looking into are (1) an attional battery supply to augment the current AA and AAA's, (2) external flash, (3) option to power calc from a USB port, (4) a reset switch in case your ASM game crashes. There's a couple other options that are less likely.

Anyway, the Calc DBS is nearly 1 year old now and I've had no problems with it to date. The year also required only one battery replacement, despite my love for cheap, generic battery brands; and many game marathons with ZTris, Phoenix, Mario, Slippy and other favorites. Cool

frenchcalc1 · Posted: 15 Apr 2007 12:51:02 pm Post subject:

Dude, that looks awesome! how long do your batteries last with DBS?

DigiTan · Posted: 16 Apr 2007 07:05:31 pm Post subject:

I never got around to timing it like I originally planned. But at the time of development, I estimated it at nearly 24 hours when AA's and AAA's are used.

R3D_bull43 · Newbie Joined: 19 Jan 2008 Posts: 5

so does just work for the TI-82 or can it work for a lot of 8x's? maybe like a 83+? this is awesome :biggrin:

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