Calc DBS: Pimp your TI

DigiTan · Post by **DigiTan** » Thu 27 Apr, 2006 4:42 am

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.

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. As such, you can now unplug whenever you want.

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 · Post by **elfprince13** » Thu 27 Apr, 2006 5:04 am

I will buy this from you....heh....I wish.

kalan_vod · Post by **kalan_vod** » Thu 27 Apr, 2006 5:18 am

Wow, this sounds really awesome. I think you should tell TI about this after completion

...

Timendus · Post by **Timendus** » Thu 27 Apr, 2006 11:45 am

Wow, that's pretty advanced stuff

But I normally don't use my hardware anymore, just PTI

threefingeredguy · Post by **threefingeredguy** » Thu 27 Apr, 2006 3:09 pm

No blur? How will we do grayscale? Still, it's really really cool.

Post by **benryves** » Thu 27 Apr, 2006 3:38 pm

Hardware-related stuff always gets a thumbs up from me!

Very cool.

KermMartian · Post by **KermMartian** » Thu 27 Apr, 2006 3:58 pm

Lookin' sexy. When are you going to start selling them on eBay?

DigiTan · Post by **DigiTan** » Thu 27 Apr, 2006 8:09 pm

threefingeredguy wrote:No blur? How will we do grayscale? Still, it's really really cool.

Ooops, I guess I left out that detail: all greyscale still works. It's just the keypress blinking that's gone. When it's plugged in, you can lock your contrast in on level 2 so the screen looks like you always have a set of brand-new batteries in there. It's also cool because fast-moving sprites won't disappear like when the batteries are weak.

It's been a big hit with the math club. I might be able to build a few more on an individual basis, but it's kind of a stretch. Might try ebay.

Post by **L4E_WakaMol-King** » Sat 29 Apr, 2006 12:28 am

What are you charging for them?

kalan_vod · Post by **kalan_vod** » Sat 29 Apr, 2006 3:24 am

I am interested in what is needed to make one, and the cost to do so

.

DigiTan · Post by **DigiTan** » Mon 01 May, 2006 4:07 am

Ignoring the batteries, the total cost was around $20 or $25. Most of that was from the plastic RadioShack and Velleman casings. I can get an exact figure once I find all my receipts, but in general the device (intentionally) used very few parts.

For the summer at least, I'd be able to sell individual ones at cost. Otherwise, I might build an identical unit for my other TI82 since its EED was removed.

CompWiz · Post by **CompWiz** » Mon 12 Jun, 2006 2:10 am

so, do you have plans available for this yet? I was looking forward to trying this out.

Hmm, I wonder how far you can overclock it with all this extra voltage?

also, you mention that this could recharge Ni-cads, how about rechargable NiMH battries? The chargers for them say that they support NiMH or Ni-cad batteries.

Post by **tr1p1ea** » Mon 12 Jun, 2006 6:42 am

Whoa, this is really cool DigiTan!

.

The built in chick magnet is probably the best feature

.

CompWiz · Post by **CompWiz** » Mon 12 Jun, 2006 1:51 pm

tr1p1ea wrote:The built in chick magnet is probably the best feature .

yeah, how well does that work?

DigiTan · Post by **DigiTan** » Thu 15 Jun, 2006 3:07 pm

Well, it'll definately help us score with the calc babes. And by "score" I mean 2P arcades like ZTris.

I got sidetracked working on 83+ stuff, but the plans are still being published.

As for recharging, the effect is really limited right now (months to reach a full charge by my estimate). It's good news for conventional batteries, but I'll have to make a specialized version for battery-charging to work. Coincidentally, one of TI's subcontractors specializes in top-of-line recharger chips that will probably be the focus of the next Calc DBS upgrade.