Archive for March, 2007

Nintendo DS current consumption – hahd numbahs

Background story
So I was busy homebrewing on my NDS, even bought myself a DSerial board to use it as an ultraportable serial/debug console. I had a few ideas for the much faster, native parallel interface too, so when we were sending out boards at work, I threw my own “DParallel” onto the layout. The boards came back, and we had to cut them apart…note to self: DO NOT let your machinist saw apart your boards on a huge gritty band saw. As is semi-common practice (and just like on the DSerial) I laid out a big VDD (main system power) plane on the bottom of the board and a big GND plane on top. Before inserting the board, I peered down the sides of the card slot to be sure they weren’t metal that would short against the sides of the board, and even performed some quick “due diligence” checks with an ohmmeter to be sure I didn’t do anything stupid (such as somehow shorting VDD and GND together) that would result in frying my DS.

Satisfied that all was well, I popped the board in, hit the power switch…and proceeded to fry my DS :-(

Turns out that the top and sides of the card slot are plastic, but the back surface (hard to see in an all-black DS) is METAL, and it’s connected directly to ground. Combine this with a big VDD plane in direct contact with it, and some rough board-sawing leaving some exposed copper on said plane, and a heap o’ trouble ensues.

Anyway, due to some smart engineering by the big N, I am spared from my own stupidity (it just blew an internal fuse). Googling for Nintendo DS power consumption specs to figure out what replacement fuse I needed, I saw just forum posts with educated guesses ranging from ~ 300mA to upwards of 1.5A. So while I had it under the knife, I decided I’d settle the question once and for all.

Current Consumption Numbers:

All measurements taken on a DS Lite “revision as of Jan. 07” at 3.70VDC, the nominal voltage of the battery pack.

Quiescent (power OFF, just running the realtime clock)…1.3uA! (This is Sweet F-All.)
NDS Boot screen, no cartridges installed…
Screen brightness 1 (lowest) : 54mA
Screen brightness 2 : 81mA
Screen brightness 3 (default) : 128mA
Screen brightness 4 (brighest) : 180mA

All the following measurements taken at Brightness level 3 (default) unless otherwise noted.

DS Download Play (Wi-Fi module active/scanning) : 177mA
Pictochat (Wi-Fi active) : 140-184mA

With Supercard SD installed….
NDS Boot screen (Pictochat / Download Play selection screen) : 159mA
GBA mode (bottom screen off, probably ARM9, 3D engine and a couple other things powered down too) : 98mA
SuperCard home screen: 165mA
Playing a movie using Moonshell (bottom screen off, 2D) : 118mA
Moonshell ‘idle’ (both screens off) : 67mA
Metroid Prime Hunters (both screens active, 3D, heavy Flash seeking) : up to 190mA
Running “WiFi_Example1” (both screens and WiFi active) : 228mA
WFC “Search for access points” : 228mA
“Almost Worst Case”: Running Wifi_Example1 at full brightness: 278mA

Worst case seen: ~ 290mA

Base… 36mA?
1st brightness level: add 18mA to base
2nd brightness level: add 24mA to 1st brightness
3rd brightness level: add another 47mA…
4th brightness level: add another 52mA to all of the above

(Total power savings by keeping lowest brightness: 126mA)

SuperCard SD: add 31-37mA while idle…a bit more while reading/writing the SD.

Bottom screen @ default brightness: save 47mA by turning it off

WiFi enabled (“new” 1/2007 DS Lite wifi chipset) : add 49 ~ 63mA, varies based on what it’s doing.
Around the tail end of 2006, Nintendo switched to a different WiFi chipset (sorry, can’t find any more info online from DS forums, etc…only the code changes in libdswifi CVS to accommodate it). This is the one I have. Power draw results for the previous chipset could vary from this.

Fictional (best case) playing times:
Numbers obtained by dividing battery capacity (1000 mAh) by actual current consumption. The “mAh” (milliamp-hour) rating means the battery can in theory supply 1,000mA for 1 hour (or 100mA for 10 hours, etc.).

These are rough ballparks that assume 100% conversion efficiency, extracting 100% of the power out of the battery, and all kinds of other things which do not reflect reality. Your real numbers will be lower.

Brightness 1 (min), no cartridge: 18.5 hrs
Brightness 2, no cartridge: 12.3 hrs
Brightness 3 (default), no cartridge: 7.8 hrs
Brightness 4 (max), no cartridge: 5.5 hrs

As you can see, backlight setting has a large impact on total run time!

Let’s assume default brightness for now…

Pictochat / Wifi download play: 5.6 hrs
Running SuperCard SD: 6.1 hrs
Running SuperCard SD with intensive game: 5.3 hrs
Running SuperCard SD in GBA mode: 10.2 hrs
Running Wifi app/game from Supercard SD: 4.4 hrs

“Low Battery” threshold: about 3.70V
Low battery automatic shutdown: about 3.44V

Startup current profile, no cartridges:
Initial phase: 20mA (screens off, power indicator dimmed)
Second phase: 85mA (screen backlights on, still initializing things)
Fully initialized: 128mA (default brightness)

Fuse sizing (for everyone else who did something dumb and blew F2): I had some 500mA 0603 surface mount fuses laying around (Rezu project represent!), so I used one of these. I think it’s a good number given the above. Worst-case power usage I could produce was just a hair under 300mA, but some other DS slot 1/2 cards (games, flashcarts, rumble paks, specialty cards like the Opera Browser cart with onboard RAM) may draw more juice (still, I doubt it would bring the total over 500mA). Even if you’re sticking your own Pentium 4 accelerator card in there, I wouldn’t advise sizing the fuse above about 750mA, absolute max. It’s there in part to keep the Li-Ion battery pack from going all Sony Vaio on you and melting your pocket into hot slag if something in the DS shorts.

Text on the new Mitsumi wifi module:
IC: 4250A-DWMW006
(“R” symbol) 007NTCUL0121
Made In Philippines

Mitsumi’s web site provides no evidence that this module actually exists, of course.

Odds & ends

fr33 mp3z d00dz

Here’s a kickass site I found: Jamendo. Download and share mp3s, free & legal, without worrying about keeping the RIAA out of your cornhole. All albums released under a Creative Commons license. (And they’re actually pretty good!)

Sync on Green, or something to that effect

I’ve long been bothered by an unparseable street sign endemic to New England: “Bicycle Stop On Line for GREEN”

Err.. does that mean stop while(green) (a la “I brake for teddy bears”), to avoid being clobbered by people making right turns? Or does that mean stop UNTIL green (while(!green)), the way the secret red/green traffic signal color code works in most other places? A mixture of boredom and curiosity had me research this today.

Short answer: NEITHER.

According to this, this strange sign was originally supposed to say/mean “Bicycles stop on (indicated spot) to request green”, since bicycles don’t have enough metal in them to trigger the inductive car-detector loops embedded in the road in most places (same reason you can’t walk up on a drive-thru and get service). The plan was to place a mark* to indicate the edge of the loop, where it’s most sensitive. The actual sign text, and the lack of any actual mark (or correctly placed mark) on most streets is, as you guessed, the result of Mass. Highway Department bungling.

the smell of vinyl in the morning

My office building was recently recarpeted. As part of the lease, everyone in possession of a wheely chair now has to have one of these silly plastic chair mats under their desk. They’re brand-new, and whatever plastic they’re made out of is the same kind they use to make inner tubes and other swimming pool toys. Now everytime I come into my office it reminds me of inflatable alligators.

(Between that and the fumes from the new carpet and carpet glue, I’m really enjoying coming in…just not getting much done…)

Have ye tried… the power button?

Speaking of the office, it’s great that we have an electronic engineering department. During the recarpeting, our Pure Water Technologies water cooler, which btw is a piece of crap and in for repairs it seems on a weekly basis, had to be unhooked and temporarily moved. When it was hooked back up by AC, MvS sent out an email saying the cooler was hooked back up, but the “hot” tap wouldn’t be hot for a little while yet. A couple minutes later (presumably not seeing this message), AC sends out an email saying the cooler is back, but to wait a little while for hot water. Pretty much word-for-word identical. This email pair was amusing (again, in the you-had-to-be-there way), resulting in a cascade of humorous replies which won’t be repeated here. Anyway, this morning the hot tap still wasn’t hot, so more emails. AC scratching head, and there’s talk of sending the unit back (again) for repair. This is when the EE swoops in to save the day, finding the big red “Hot Tank” switch on the back and flipping it from the OFF position to the ON position. Eh…

Tests Tim Can’t Pass (check all that apply): [x] Math [x] Blood [x] Field Sobriety [x] Turing [x] Voght-Kampff

So I was surfing teh intarweb yesterday, on a Japanese site via Google Translator (I was, er, mostly interested in the pictures). All of the sudden, instead of unintelligible translations I’m getting this error page. Google thinks I’m spyware! (Now granted, the typical male specimen looking at the internet’s primary content-type* may approach the task at “hand” with machine-like precision, but seriously. Run a virus scanner?)

This part amused me: “We apologize for the inconvenience, and hope we’ll see you again on Google.” Actually, if you’re Google, and think I’m a zombie botnet machine, you’re (aside from undertaking technical measures to ensure same) hoping you’ll NOT see me again :-) This line is as authentic as “I don’t mean to be a dick….”

*There aren’t, and never were, any lines. There’s supposed to be a white bike symbol, but many contractors claimed that they were unable to paint a symbol that small. Pardon? They should talk to the local graffiti artisans in my area, who can scrawl on jagged cinderblock with a resolution of < 1/8". ** Content-Type: Image/jpeg Content-Disposition: Smokin'

Ya, I was bored yesterday…

So I took stuff apart. Here is some more on my cry for help unusual fascination with small display devices – a teardown of a cheap, undocumented LCD to figure out how to make it work, and document it for everyone else out there on teh internets who wants to use this display in some project. If nothing else, it features some pretty pictures of a colorful semiconductor die under glass, taken with Kick Ass Camera macro focus.

Belated St. Paddy’s post

Not much to say, but nothin’ says St. Patricks like a good old-fashioned piss-up. So I took a break last saturday night from reading about Paypal shopping cart integration APIs (you can’t set different shipping rates for Boston and Botswana? Gimme a friggin’ break!) to find out what some buds were doing. “Hey, we’re down at the Banshee, come join us!” So I made my way there.

Anyway, I think I must have a neon “crazy people please come talk to me” aura or something, which was particularly acting up tonight. Not 2 blocks from my house I run into Powderhouse Crazy Guy (or rather, see him bothering some people in front of me and cross over to the other side of the street, because I’m in a somewhat less than friendly mood and don’t want to deal with that right now). But I didn’t cross fast or sly enough, I guess, because next thing I hear is running footsteps and “Uh…Eyy…Eyyyyy!” from behind, followed by some pokes on the back. I was walking quite a bit faster than the pack of people on the sidewalk up ahead of me, which turns around in response to the commotion and immediately parts Red Sea style, giving some looks that I couldn’t reliably interpret–either pissed that I’m luring this guy (however inadvertently) into their vicinity, pissed about me rudely ignoring him, or just throwing a big collective “like, wtf mate?” to the whole business. So I end up going right through the center of this crowd, the guy keeps on poking, and I guess either found someone else to chase or got too far away from Powderhouse for his comfort, because the footsteps and poking died off. I didn’t look back to see which.

So I make it all the way to the T without further incident, get on and sit down. The very next stop, a guy comes in and sits right next to me (rather than leave a space, I mean, this was not a crowded train), smelling of equal parts rum and feces, turns and asks “which one’s my stop?”, or something to that effect. Ummm….okay…? With some questions I eventually I work out from a long and incomprehensible story that this guy’s from “Califorrrrn-i-ya” and trying to get to the airport for his return flight. I tell him he’ll be getting off at South Station, which is now coming up in 5 stops. So he’s like, “what’s the next stop?” And I tell him, pointing to the sign right in front of us which has all the stops listed. “What’s after that?” Repeat for each of the stops, and repeatedly directing the guy to the big sign, pointing at where we were now, all that. So after Downtown Crossing, I tap the guy and tell him his is the next stop, and try to explain how to go down the stairs and get on the right silver line bus, not making much headway. So he kind of just sits there as the train grinds to a halt and the doors open, and I’m prodding, “dude, get up, this is your stop, the doors are going to close!”, but the dude just sits there and stares like no comprende. About 3 seconds after the doors are shut and the train has started moving again, he gets up and goes for the door, and comes back looking all quizzical on finding that it’s not open. So I instruct him as plainly as I can to “walk out this door, walk a few steps forward (to the ‘inbound’ track); when the train comes, get on it and go ONE STOP”, and he actually gets off in a timely manner next time the doors open. What happened after that, I don’t know. After the doors shut I sighed loudly, and a couple passengers smiled knowingly. (This whole exchange was pretty comical in the “you had to be there” sort of way.)

Onward to the Banshee! A couple blocks off the subway, down an alley there’s a pre-fight argument going on…after the my luck so far I figure the best thing I can do is walk quickly past and not make eye contact. This is in Dorchester, which is not necessarily the nicest neighborhood, and on one of the biggest drinking nights of the year, so it’s probably not a huge surprise. And man, the Banshee was assholes-to-assholes packed. It took over 10 minutes to get from the front door to the back where our folks were hanging out. And as for actually buying a round…another 20 minutes to claw one’s way to the front of the bar, get attention and put an order in, so I made each one a bulk order ;-) A couple of our group members had been there since 8:30 in the morning. There was much off-key singing and The Lady dancing in a very lubricated fashion with a big green foam hat.

SpaceAliens and ponies

Not a rant on politics (and indeed, I’m not stating a position), but a rant on language.

At one point when I was a young ‘un, there was this high-sugar kids’ cereal commercial (I think it was for Cap’n Crunch) where one of the characters was rattling off a long list of those who couldn’t have any*. All I remember of it was “…and space aliens, and ponies, …”. I asked my dad why they explicitly said space aliens, because weren’t all aliens from space? He explained that they were probably trying to avoid offensive connotations, because “alien” could also be taken to mean illegal alien, a term I had never heard before (and which required some explaining).

Over the years, this fell out of favor for (along the lines of the well-known George Carlin euphemisms rant) illegal immigrants, then migrant workers. I had to laugh a bit (in a totally non-funny way, the way one laughs in a graveyard) in GJM’s car yesterday when he was listening to a debate on NPR and they kept referring to guest workers. GUEST WORKERS.

*Common theme in kids’ cereal commercials, silly rabbit: the assertion that the product is enjoyed exclusively by an elite class. Hardly surprising from an industry that derives much of its methodology used to this day from experiments performed in token-economy systems in mental hospitals.

Warning to bachelors: bleach eats clothes

I always thought bleach was used for getting unwanted colors out of clothing. Like, say, coffee colors. So I tried this the other day – it worked great! Kind of like cutting around the stained part and throwing it away, but the bleach method saves the trouble of finding scissors.

Category: Things heard while coming out of sleep (hey FCC, do your job!)

For suitably large values of emo singer, “inside of me” and “in sodomy” sound exactly alike.

Ice cream the geek-fashioned way

My lab had this huge tank of liquid nitrogen left over from an experiment, with a little bit left in it, just kind of waiting for it to all boil off so we could return the tank (or so I presume). So instead I rounded up a posse and we used it to make ice cream.


Grabbing ingredients ultimately involved a trek to four separate stores. Costco for milk and cream in-quantity, Shaws for cherries and sprinkles, etc., and an almost-futile search for el-cheapo styrofoam coolers to transport LN from the lab to the kitchen upstairs. Normally you’d use a very well-insulated Dewar flask for this, but we don’t have a Dewar, so a doos will do us. Eventually we found some at K-mart, but had to beg an employee to fetch us a couple from storage (apparently people don’t buy coolers in the middle of winter). Cooler Trek left me about half an hour late to my own shindig, but people were still around.

Making the stuff
As a hedge against possible breakage (and because the styro coolers were a bit on the thin side, K-mart special), two were stacked one inside the other and bonded together with Duct Tape, one bit of equipment my lab always does have in abundance. First challenge now was to get the LN safely out of the tank. We should have a long metal pipe for this, but we don’t. Enlisting the help of TvS, we found what (at room temperature) appeared to be an ideal solution, a hard clear plastic/rubber hose reinforced with thread inside. Shoehorned this onto the tank’s output nozzle (there was some heatgun involved), then let ‘er flow. Maybe half a minute of hissing, and about a drop of LN actually reached the cooler before there was a loud SNAP and the hose shattered.

Plan B: We had someone hold the tape-reinforced cooler pair directly up to the nozzle at an angle, screwed the valve open and crossed our fingers. Hissing, fog, lots of spraying, and eventually LN started to stick around long enough to stay liquid upon hitting the bottom of the cooler and collect there. After getting a nice 4" or so, we shut the valve and ran the cooler upstairs. From there it was pretty straightforward: about a 50/50 mix of milk and heavy cream (or substitute Half and Half), about 1 cup sugar (scale depending how sweet your flavoring is) and 2 tablespoons vanilla extract (according to JR this is critically important; don’t ask me why) to every 10 cups dairy, and of course your flavor ingredients. For the first batch we went with blendered marischino cherries and chocolate chips. We even (with proper supervision of course :P) let the kids in the group scoop out the LN, boiling vigorously in a plastic ladle, and apply it to the ice cream in progress. Dropping a marshmallow Peep into the cooler, extracting and shattering it (incompletely) was also demonstrated. First ice cream batch turned out yummy, and extremely cold.

Once the kids were heading out, we pulled off a fresh cooler of liquid nitrogen and it was decided to give the 2nd batch more of an adult theme. Out came the 1-liter Jug o’ Bailey’s, which was substituted for half of the half and half, and mixed with crushed chocolate bar flakes. Bailey’s (or other booze) ice cream is a special LN treat; due to the alcohol content it can’t be frozen in a conventional ice cream maker or freezer (either well or at all, depending how nippy you make it). This batch was pretty nippy. I think it gave me freezerburn of the tongue however.

More goofing off
Since we still had some LN sizzling away in the cooler (and slightly thinned bloodstreams from Batch #2) some of the berries that didn’t get used in the ice cream wound up in the cooler instead, then on the floor in dozens of pieces. Peep-shattering didn’t work as well (probably due to well-insulating marshmallow fluffiness), but strawberries and blackberries break satisfyingly on impact.

My small video & photo album of the event. There would be more, but guess who forgot his 2gig memory card at home and had to steal a little one out of his gameboy DS? :-P


My office is at the front of the building, with a large picture window overlooking a stunning view (okay, overlooking the Fire Lane and 2-story parking lot). So the building’s comings and goings occasionally catch my attention.

In a span of 3 days, I’ve seen two ambulances quietly show up (no flashing lights, no sirens, and no discernable hurry), accept delivery of a gurney, and just as lackadaisically drive away. I didn’t catch a look at the first one, but yesterday’s wheeled a pale, closed-eyed, motionless ( i.e. downright dead-looking) old man right past my window on the handicap ramp* during the on-load. The statistical matters (2 occurences, 3 days, and that’s just times I happened to be in-office AND notice something through the cracks in the vertical blinds), besides the obvious matter of potential cadavers floating past 5 feet away from my workstation, left me a little squicked. Surrounded mostly by unspecified researchers ( i.e. a paper sign recently appeared on the front door pointing “sleep study” participants to the side entrance) and anonymous biotech start-ups, I want to know…what exactly is going on in my building?

On a semi-unrelated note, I got out of my car yesterday in said parking lot, happened to glance in the backseat of the car next to me and… who the hell keeps a copy of the DSM-IV in the back seat of their car?

* Handicap ramp, n. Place outside where the entire buildings’ worth of smokers congregate (because they get shooed away from in front of the front doors by management) right in front of Jeff and I’s windows and smog us out of our office.

Yep, it’s finally come to pass…

It’s official, I peddle adult toys on the internet. My folks would be so proud.

(*Yes, I still have a day job. Hopefully I’ll still have it if this ever gets around the office ;-)

Wicked Smaht(tm) idea of the week

My dishwasher is running. There are knives in it. With wooden handles.

Back home, this would have been a good way to get howled at. Or possibly get one’s hide tanned. Apparently dishwashers are bad for wooden silverware. Now, being an old-fartass adult, I have a better solution to this quandary. Put the wood-handled knives, which I think belonged to a former housemate, in the dishwasher anyway. Use them in this manner to failure (possibly years from now), then get smart and replace them with knives that can be dishwashed.

* * *

One of these days, whether it sounds like an appealing idea at this stage in my life or not, I will probably end up married. (Considering that the typical alternative is dying alone, yeah, getting hitched is sooner or later going to sound like a pretty good idea.) And once this happens to a guy, he’s begun inexorably down that slippery slope toward Kidsville. (The coefficient of friction on that slope varies for each relationship, but is typically less than infinity.) Upon entering the town of Marriageville (population: 2, in ideal cases) on a full head of steam, the first thing to do is settle into a house, fleshing it out with good furniture, power tools, big speakers eh-hem, floral patterns, and all this other weird stuff. One of these pieces of furniture will contain Fine China. Let’s ignore that one for now; if one of those appears in my house, it will be equipped with high voltage, caltrops and laser death rays just to avoid the howling when a piece in an undersecured china cabinet invariably gets broken. Which brings us to the Lesser Dinnerware, the kind mortals actually eat off of. My first post-marriage task (after carrying her over the threshold, letting go of her hair, and putting down the club) will be to source replaceable dinnerware. Because, upon crossing the city line into Kidsville, they hand you some free kids, which like to run around and, in the course of said running around, break shit. Advanced statistical models tell us that dishes are going to get accidentally smashed, dropped, fumbled, and/or pulverized by errant baseballs multiple times throughout the MTBF of a typical marriage-with-kids. Although a common parenting mistake (so says I as not-a-parent), there is no sense in getting universe-crashingly upset about this; it’s going to happen. Therefore, Limited Edition, Matched (unsigned int)n-piece Sets are a sucker’s game.

In tech products, be they electronic, mechanical (engine components), whatever, a discontinued part in an end product means a costly oh-shit-whaddwe-do-now redesign–those companies know this, and try hard to have a reputation of having their parts available for years, with a well-established and published lifecycle (Advance/Preliminary, Active production, Mature, End-Of-Life, Discontinued) so that engineers, fearing those costly Discontinueds, will comfortably use their parts. The same is not true for dishes. The final dinnerware specification will weigh such factors as aesthetics, volume capacity, microwave and dishwasher compatibility against the ability to replace elements of the set, i.e. expected production status over the next 10-15 years. If any non-crappo dishware maker applied this component-sourcing strategy and could make the promise of long-term stable production of each item, they’d make a killing.

Skiing at Smuggler’s Notch in VT!

Pictures here

Three days of skiing, 2 nights of our own lodge, Real Fire, marshmallows and roastin’ sticks, hot chocolate with Bailey’s, pool and jacuzzi across the street, kickass food, and zero Ski Patrol involvement this time ;-)

Oh, and we found GJM’s long-lost babymaker.

Asshole Mirror (drivers piss me off)

A road-doofus encountered on the way back from skiing reminded me of this old newsgroup post I made somewhere, so I dug it up:

I want an automatically-actuated “asshole mirror”. I keep one in the center console for those special occasions, but it just isn’t the same. It’s for that asshole, you know the one, in the SUV who sits two inches off your back bumper giving you a suntan with his brights. That’s when the asshole mirror comes out – hm, down a little…a little to the left…Bingo! He’s slowing way down.

…wait a minute dude, that wasn’t supposed to mean “pull into that ditch over there, roll over twice and burst into flames”. Damn.

QOTD: “I assume that’s not meant for us, right?” –Backseat passengers, noticing my “1-bit digital communication” to the motorist behind us.