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Wow, the TI-89 uses an RC oscillator for its clock! That kind of clock is one of the cheapest and least accurate, so I wouldn't want to run a real-time-clock off of it. I wonder if they have some sort of calibration mechanism on the production line, or if the processors are so underclocked already that they will surely work with a large variation of clock speeds. Even after leaving the production line, RC clocks drift and are more sensitive to temperature, so TI must always leave plenty of speed margin.

Commenting on his remarkable success, Bill said "I've spent 25 years on 80 & 160 listening to below noise level signals ..."

Below noise signals sounds paradoxical, but people do it all the time. If you're in a noisy restaurant, you can pick out individual noises even though they are much quieter than everyone else. The key is that you have an idea of what you expect to hear - you generally know the tone of their voice, know what sounds make words, know what words make understandable sentences.

Imagine if the signal had been spread-spectrum. Spread-spectrum signals are stealthy because, they to, can be recovered from below the noise floor. Basically, with an idea of what to expect, the receiver's processing can effectively raise the signal above the noise floor. Instead of sending short tones for each bit, a series of tones are sent for each bit (a chip) - one chip for zero, and a different chip for one. It's a lot easier process a sound and see which chip it sounds closer to than it is to see if one particular tone is there or not.

So, in summary, this guy's brain played a lot in the reception to pick out a signal from the noise. I wonder if the next record will be set with a spread spectrum transmitted signal and a digital processing receiver.

http://www.maxim-ic.com/products/ibutton/ and, more specifically,
http://www.maxim-ic.com/products/ibutton/ibuttons/ java.cfm

Read the second link for all the tech-details. These things are pretty amazing:
durable, cheap, crypto-secure, and can be mounted on a key fob, ring, watch, or
other personal item...whatever thing it is that you, personally, have spent
your whole life learning not to lose.

When I started learning about everything they can do, I was amazed that they
weren't more widely known (although there are more than 85,000,000 of them in
use around the world.) Slashdotters looking for new toys to tinker with and
code for would do well to look at this platform. It's ripe with options,
capabilities, and possibilities.

http://www.maxim-ic.com/products/ibutton/ and, more specifically,
http://www.maxim-ic.com/products/ibutton/ibuttons/ java.cfm

Read the second link for all the tech-details. These things are pretty amazing:
durable, cheap, crypto-secure, and can be mounted on a key fob, ring, watch, or
other personal item...whatever thing it is that you, personally, have spent
your whole life learning not to lose.

When I started learning about everything they can do, I was amazed that they
weren't more widely known (although there are more than 85,000,000 of them in
use around the world.) Slashdotters looking for new toys to tinker with and
code for would do well to look at this platform. It's ripe with options,
capabilities, and possibilities.

Those Dallas Semi (Now Maxim Semiconductor) http://www.maxim-ic.com/ chips are cool. I should be getting some of the ibuttons and ds 1 wire chips in the next 3-4 weeks.

But it takes time for the contract shops to get up to speed just ask NVidia ;->

Anyone who frequents Laser Quest (a laser tag arena) knows that they use Maxim/Dallas Semiconductor iButton devices to activate the "blaster" with your callsign and to keep track of statistics. The problem with this is that anybody with a knowledge of microcontrollers and some basic hardware skills (such as, ahem... moi) can rig up a simple unit to read and write to them (using a serial protocol called 1Wire). While this might not seem particularly relevant to the topic, it demonstrates the same concept, which is that if you make widespread use of a low-cost technology that nerds have free access to, it's only a matter of time until one of them starts to get curious. And then you're screwed. ;)

According to this link, LEDs with 'drive efficiencies' greater than 90% are available - this is just the first link I picked.
IIRC LEDs in general are the most efficient common light source available, and the longest lasting. Friends in the volunteer fire department use LED flashlights now, because their brightness is the same as regular flashlights but they can be left 'on' for almost a month before wearing the battery down. That's about 240 times better energy efficiency.

I'm betting it's an electrical disturbance

Doubtful 60 Hz would cause a problem at 315 MHz, which is typically used for remote keyless entry..

It'd be amusing to wonder about HAARP as well, except 315 MHz is a little high for its reach (actually, quite a bit high).

Quite an interesting situation though...

The circuit you describe can be used for small loads. A computer is going to require a larger more complicated supply. An example. Figures 2 and 3 show the heart of the DC-DC conversion. This circuit has an output of only 3.3v and 10A (33watts). Additional output stages (fig 3) in parrallel could be added to generate the other voltage levels. Ofcourse you would probably have to beef up the input stage to supply more then 30watts. This gives a good idea how complicated DC-DC powersupplies can be.

I do not dispute that a regular motherboard can run off of a battery. Motherboards are not designed with low power in mind though. A generic computer (without display) is typically going to burn 100watts or more. This is considerably more then most laptops with display.

It is possible to run off of battery as you describe. I don't see it as viable in the long term. You would be surprised how quiet some of Honda's generators are. The EU3000 in particular produces only 58dBa which is quieter then most air conditioners. But neither portable generator or car based battery chargeing is going to work for anything more then casual use (weekends). A proper installation of fuel cells or other generator is needed. We haven't even touched on the power requirements for drinking water.

If anyone is looking for a generator to power a cabin on the weekend take a good long look at the EU1000, EU2000, EU3000 from Honda. Very quiet and long run times.

I have heard good things about the Dallas DS80C400 controller. It's an 8051 core which is great 'cuz you can take advantage of the huge 8051 experience base out there, it's got 10/100 Ethernet with TCP/IP, DHCP, even IPv4 and IPv6 . It has a direct memory access mode which makes it really nice for moving good-sized chunks of data without bottlenecking in a microcontroller's tiny RAM area.

So you don't get 100mbps speeds, more like 5mbps. But for an all-in-one microcontroller, it's ripe for some really neat little devices. You! Give your toaster, microwave, breadmaker, washing machine, garbage disposal, TV, stereo system, and coffee maker IP addresses. Now!

Hit a secret little button, and the stereo switches to slow music, the lights dim, annoying rackety appliances shut down, the TV turns off, and the warm smell of toasting cinnamon-rasin bread fills the room...wait, that was for breakfast. Oh well.

As has been mentioned elsewhere, if you're going to record LPs on your computer you have to pipe your record player's outputs through a phono preamp. You can use an old stereo with a phono input or a discrete phono preamp.

I've been looking into making a discrete preamp for a while. There are many circuits available on the web, some more complicated and some more simple.

My first try is going to be the second one on this page. Interesting note: It looks like maxim thought it was good enough to copy in their application note.

You may find the OpenBrick to be a good starting point. They take 2.5" drives and run off 5V. Build a DC->DC convertor circuit using something like a MAX787, or (if you have more heatsinks than time) a 7805, and you should be able to run it off a lead-acid battery a very very long time.

I have no association with them.

Unfortuate that I forgot that V/Ah = Wh.

Though according to your math (and mine) 3.2wh * 3600s = 11,520J Not the 1152 as stated. Right?

That would be:
3.2 * 60 = 194
194 * 60 = 11,520.

@ .2J per 200W 1ms pulse - that is 58,320 pulses. I say, I say, boyyyya, that's a lot of pulses.

Now... with that said the question is weather or not your phone actually radiates 200W of power at any given point in time, which is really what this whole thing is about.

I found this link: Maxim CDMA Chipset Specs which is a pretty standard cdma chipset for a cellphone phone. The max power output for the chip is is 39 DBm which is equivalent to about 6 watts. Back to one of two points earlier, a cell phone does not produce 200W RF.

The other point was an attempt to prove that the phone doesn't have the capacity to produce 200W for 1% duty cycle. While this is still a true statement, my calcs for it were way off (i'll be sure to check my units next time).

As for being stubborn, maybe a little. I'm interested in people proving what they say. The arguments about cellphones can most certainly be proven quantitively and should be. Instead of asanine remarks along the lines of "because my monitor shakes, the phone MUST produce 200W." It's foolish to draw such a conclusion. I'd have to think that you would agree being of a learned background.

-ZebraX

I would use the term "satisfaction"; I remember being very pleased with myself for coming up with a sixteen bit by sixteen bit shifting multiplication algorithm in just 24 instructions or realizing that self-modifying code is needed to perform an indirect jump or data access anywhere in the 16 bit address space.

The 65C02 added indirect and indexed indirect addressing to JMP (previously, only absolute addressing was available).

What I think was my most clever hack was a routine to play WAVs (11.025 kHz 8-bit mono) on an Apple II with no additional hardware. 73 bytes on page 3 was all it took to play sounds through the speaker with a resolution of 4 bits per sample. Source code is here.

More recently (just a few months ago), I wrote some code to communicate with Dallas Semiconductor's 1-Wire devices through the joystick port. I used a temperature sensor and a clock chip to turn a II into a programmable temperature controller for my beer fridge. In addition to maintaining a set temperature anywhere from the 70s down to the 30s, it also manages gradual temperature changes (1/hr) for different stages of brewing--primary fermentation, diacetyl rest, lagering, etc. The code to do all this is GPL'd; I just haven't gotten around to putting up a page on my website for all of it yet (though the 1-Wire primitives are available through this page).

First, NTSC signals are analog, which means there is virtually infinite horizontal resolution.

Oh for fucks sake would you freaking idiots stop it with this "infinite analog" bullshit. The NTSC standard allocates 4.2Mhz of bandwidth for the colour signal which works out to 450 "pixels" of horizontal resolution.

Read this.

I use digitemp too to monitor the temperature of my basement....errrr...server room. It works very well and yes, Dalsemi does have one wire humidity sensors

I currently use digitemp to monitor the temperature in my computer room using Dallas Semiconductor DS18S20 temperature sensors. I had thought that they also had iButtons that also monitored humidity, but I don't see them now.

I currently use digitemp to monitor the temperature in my computer room using Dallas Semiconductor DS18S20 temperature sensors. I had thought that they also had iButtons that also monitored humidity, but I don't see them now.

There are probably 6v to 120vAC power inverters which should do the job just fine, and will be the easiest and fastest way to go. Just plug your power adaptor into it and then into the laptop and you're done.

I suspect they are rather expensive though.

The other alternative is to make an adaptor that goes directly from the battery to the powerbook. Since you didn't give any specs on the power requirements of the laptop you're talking about (and yes, the different powerbooks and ibooks have different power adaptors) then I can only give some general suggestions.

Unless you are an EE (or aspiring to be one) then don't get involved with switching regulator design and go with the option above. If you must, then go to National Semiconductor, Linear Technology or Maxim and look at their parametric guides to the power regulators. What you need is a switching boost regulator. If you are exceptionally lucky, you'll find just the part you need with the exact application note for input voltage, output voltage, and supply current. I doubt it though. Then you'll need to buy the parts and assemble it. Getting all those tiny surface mount parts on a bread board is only half the fun, though you can still get many parts in through hole.

Of course, neither of the above two methods result in a 'trickle' charge. It'll still suck power from your bike while charging, which leaves the last option:

Charging the battery directly. Just don't. If you don't know enough that you must ask slashdot (of all the places...? Why not sci.electronics.design or something? Egad...) Sorry, uh... Yeah, like I said, if you think the best place to find out is slashdot, then you don't know nearly enough to properly charge your battery directly without damaging it. Plus you still have the problems of building a step up switching regulator on top of the charger, since the battery will need a higher voltage than your 6v motorcycle cell.

However, I will give you a general overview: Battery charging is essentially a current (not voltage) operation. You force a certian amount of current in for a period of time, and the battery releases some as heat and stores the rest. Lithium Ion batteries are very finicky when it comes to charging. You will reduce your batteries capacity by 10% or more each time you charge it incorrectly. If a battery costs you $100, then it's worth doing it right, and in your case I think the only 'right' way is to use an inverter and the laptop's internal charger. Furthermore, Lithium Ion batteries do not like being trickle charged. When done properly it doesn't hurt them, but it doesn't give them a good full charge, either. Lastly, LiIon batteries are well known for their inability to take many charges. Early cells couldn't handle more than 500 charge cycles without losing most of their useful capacity. State of the art cells now don't go over 800. Trickle charging excacerbates this issue.

If you can get NiMH batteries for your laptop then I'd say you have a good chance, since you can go to your local hobby shop can get a charger from them, but they still take 12v so we're back to square one. If your LiIon is only 10.8v then you can get LiIon chargers from the model airplace community, but those are also usually 12v or 120vAC.

So, in closing, I'm still strongly advocating usage of a regular inverter with the laptop's own power brick.

Good luck on your trip!

-Adam

Yet another reason I loathe Apple (not the products, the company): they don't have power specifications on their website about the laptops. The have the input specs to the power brick, but not its output or the laptops input and current requirements, nevermind the battery V and I. I know they have to dumb things down for the average user, but at least put some real technical specs on the technical specs page instead of the fluff they currently have there.

www.maxim-ic.com

A data sheet

also check out the related products on that page.

maxim are helpfull with there sample policy. If you were to connect an array of red, green and blue LEDs inplace of the digits, you can change the brightness of each bank of them with 8 brightnesses,

In the data sheet they talk about 127 colours with bi-coloured LEDs, if you had tri-coloured then you would get... ooooh.. 16.8 million.

can be loaded by bit-banging the SPI or I2C interface from a printer port. Im sure someone has made a linux driver for it. Some code to do that was on there site when I looked but I cant find it now..

Quick answer: combine RJ45 web server with serial relay driver and presto!

There are lots of these serial relay drivers ... google for it. They have all sorts of nice features (current limit, fault detection, cascadability and are controlable through the parallel port (you have to bitbang the data and clock bits). The webserver above has 3 general purpose I/Os - enough to control a relay driver.

But, you probablly want an actual A/D converter (preferably with a current output) or a digital potentiometer. There are lots of mfgs of these products, but Maxim is pretty liberal with samples (plus they have some neat innovative products!)

Quick answer: combine RJ45 web server with serial relay driver and presto!

There are lots of these serial relay drivers ... google for it. They have all sorts of nice features (current limit, fault detection, cascadability and are controlable through the parallel port (you have to bitbang the data and clock bits). The webserver above has 3 general purpose I/Os - enough to control a relay driver.

But, you probablly want an actual A/D converter (preferably with a current output) or a digital potentiometer. There are lots of mfgs of these products, but Maxim is pretty liberal with samples (plus they have some neat innovative products!)

Quick answer: combine RJ45 web server with serial relay driver and presto!

There are lots of these serial relay drivers ... google for it. They have all sorts of nice features (current limit, fault detection, cascadability and are controlable through the parallel port (you have to bitbang the data and clock bits). The webserver above has 3 general purpose I/Os - enough to control a relay driver.

But, you probablly want an actual A/D converter (preferably with a current output) or a digital potentiometer. There are lots of mfgs of these products, but Maxim is pretty liberal with samples (plus they have some neat innovative products!)

Now for you, the Java Ring might be just what you're after. Sold by MRI, you can get ones that store, encrypt or compute. It's FIPS-140-1 certified, 134K of SRAM, zeroizes on tampering. Here is the fact sheet.

Of course, you can get a nice plain wedding band, and ask her to get you the Java Ring for the other hand. Your call.

If you want to be able to identify everybody? Why don't 'they' just implant something like an ibutton in every newborn child :P Oh, and some explosive device so it can't be removed....

Funny the current sci.electronics.* are where you can find essentially this exact advice.

You don't need to do a DC/AC/DC conversion (per se, switching DC - yes). There are plenty of DC/DC converters on the market. For example here this chip claims as much as 96% efficiency. Not bad.

In particular, this looks like it might be an ideal solution.

The answer lies in the datasheets. Many RTC chips have more than 128 bytes of NVRAM, and use a bank swapping technique to select the alternate banks. Dallas Semiconductor is one such source, although most new systems have the RTC embedded in one of the main ICs of the chipset or on the super IO chip. Here is one example, the SMC FDC37N958FR, which is used in the Dauphin Orasis v1, an SBC I am experimenting with putting LinuxBIOS on to get around certain limitations. Page 215 is the start of the RTC/NVRAM access. This particular device has 256 bytes of NVRAM, several of which are reserved for the RTC and 8051 scratchpad. Since there is only 256 bytes, there is no bank switching. The DS1251 is an RTC/NVRAM chip with 512KB of static RAM. The little bitch is expensive, too. :-) It uses a banking method where one of the normally user-available registers is now a bank selection register.

I seriously doubt many systems have more than 256 bytes of NVRAM. That is a LOT of space for settings.

Dallas Semiconductor is the manufacturer/inventor of the 1-Wire network. Take a look at www.ibutton.com for a bunch of different devices. The iButtons are 1-Wire devices in a metal can, some can read temperatures and others can be used for access control. Dallas/Maxim has other 1-Wire devices that are not in a can, these are the ones that I use for my DigiTemp kits.

There are serial and parallel port adapters available (from iButton.com or from me in my Basic DigiTemp kit which uses the serial adapter), but the bus itself can be extended pretty far. Using cat-5 cable there are people with 300m runs I believe. The theoretical limit to the number of sensors on one 1-Wire lan is unlimited, they are digital device with a 64 bit unique serial number so that they can be individually addressed.

Brian

The GPS output signals are CMOS/TTL level, not RS-232, so I put them through an MAX 232converter before they come out of the box on the roof and run downstairs to the PC. This is not exotic stuff; TTL to RS-232 converters are pretty much 30 year old technology.

The protocol is just plain async serial, so no special electronics to encode/decode.

The most extreme, fun way is to use pyrometric cones - just wait for these cones to droop and move the joystick, and you'll find out the temperature! Here's how to use the cones when upgrading the wiring of your computer.

A much more practical way is to use the Dallas Semiconductor (now bought by Maxim, and not the magazine)

Dallas has a demo application you can use as an example - a weather station and some good application note examples. It uses the DS1820 or the DS18S20 and you can get up to 2 free samples of each. This device is digital, so no calibration is needed for the accuracy you need. They have a lot of other temperature sensors; some even have alarm outputs, so once you program it, reading only one bit will tell you if the temperature is out of limits. It has a well-written and complete datasheet. They've got software for win32, linux, beos, java, and 8051. If you write your own software or modifiy theirs, you don't really need a serial port adapter; just a wire on the parallel port will do (and it will power the device, too!!)

If anyone's interested, I can dig up some c-code that I used - it works with the parallel port under dos.

The most extreme, fun way is to use pyrometric cones - just wait for these cones to droop and move the joystick, and you'll find out the temperature! Here's how to use the cones when upgrading the wiring of your computer.

A much more practical way is to use the Dallas Semiconductor (now bought by Maxim, and not the magazine)

Dallas has a demo application you can use as an example - a weather station and some good application note examples. It uses the DS1820 or the DS18S20 and you can get up to 2 free samples of each. This device is digital, so no calibration is needed for the accuracy you need. They have a lot of other temperature sensors; some even have alarm outputs, so once you program it, reading only one bit will tell you if the temperature is out of limits. It has a well-written and complete datasheet. They've got software for win32, linux, beos, java, and 8051. If you write your own software or modifiy theirs, you don't really need a serial port adapter; just a wire on the parallel port will do (and it will power the device, too!!)

If anyone's interested, I can dig up some c-code that I used - it works with the parallel port under dos.

The most extreme, fun way is to use pyrometric cones - just wait for these cones to droop and move the joystick, and you'll find out the temperature! Here's how to use the cones when upgrading the wiring of your computer.

A much more practical way is to use the Dallas Semiconductor (now bought by Maxim, and not the magazine)

Dallas has a demo application you can use as an example - a weather station and some good application note examples. It uses the DS1820 or the DS18S20 and you can get up to 2 free samples of each. This device is digital, so no calibration is needed for the accuracy you need. They have a lot of other temperature sensors; some even have alarm outputs, so once you program it, reading only one bit will tell you if the temperature is out of limits. It has a well-written and complete datasheet. They've got software for win32, linux, beos, java, and 8051. If you write your own software or modifiy theirs, you don't really need a serial port adapter; just a wire on the parallel port will do (and it will power the device, too!!)

If anyone's interested, I can dig up some c-code that I used - it works with the parallel port under dos.

The most extreme, fun way is to use pyrometric cones - just wait for these cones to droop and move the joystick, and you'll find out the temperature! Here's how to use the cones when upgrading the wiring of your computer.

A much more practical way is to use the Dallas Semiconductor (now bought by Maxim, and not the magazine)

Dallas has a demo application you can use as an example - a weather station and some good application note examples. It uses the DS1820 or the DS18S20 and you can get up to 2 free samples of each. This device is digital, so no calibration is needed for the accuracy you need. They have a lot of other temperature sensors; some even have alarm outputs, so once you program it, reading only one bit will tell you if the temperature is out of limits. It has a well-written and complete datasheet. They've got software for win32, linux, beos, java, and 8051. If you write your own software or modifiy theirs, you don't really need a serial port adapter; just a wire on the parallel port will do (and it will power the device, too!!)

If anyone's interested, I can dig up some c-code that I used - it works with the parallel port under dos.

The most extreme, fun way is to use pyrometric cones - just wait for these cones to droop and move the joystick, and you'll find out the temperature! Here's how to use the cones when upgrading the wiring of your computer.

A much more practical way is to use the Dallas Semiconductor (now bought by Maxim, and not the magazine)

Dallas has a demo application you can use as an example - a weather station and some good application note examples. It uses the DS1820 or the DS18S20 and you can get up to 2 free samples of each. This device is digital, so no calibration is needed for the accuracy you need. They have a lot of other temperature sensors; some even have alarm outputs, so once you program it, reading only one bit will tell you if the temperature is out of limits. It has a well-written and complete datasheet. They've got software for win32, linux, beos, java, and 8051. If you write your own software or modifiy theirs, you don't really need a serial port adapter; just a wire on the parallel port will do (and it will power the device, too!!)

If anyone's interested, I can dig up some c-code that I used - it works with the parallel port under dos.

The most extreme, fun way is to use pyrometric cones - just wait for these cones to droop and move the joystick, and you'll find out the temperature! Here's how to use the cones when upgrading the wiring of your computer.

A much more practical way is to use the Dallas Semiconductor (now bought by Maxim, and not the magazine)

Dallas has a demo application you can use as an example - a weather station and some good application note examples. It uses the DS1820 or the DS18S20 and you can get up to 2 free samples of each. This device is digital, so no calibration is needed for the accuracy you need. They have a lot of other temperature sensors; some even have alarm outputs, so once you program it, reading only one bit will tell you if the temperature is out of limits. It has a well-written and complete datasheet. They've got software for win32, linux, beos, java, and 8051. If you write your own software or modifiy theirs, you don't really need a serial port adapter; just a wire on the parallel port will do (and it will power the device, too!!)

If anyone's interested, I can dig up some c-code that I used - it works with the parallel port under dos.

Also the cost for these components is *much* higher than a $59 APS UPS.

However, if you wanted to roll your own you would ditch the inverter and simply regulate the gel-cel down to the +12, +5, +3.3, +2.2, etc that your computer needs, and use a DC-DC converter chip to get the -12 and -5volts.

That's much more efficient and somewhat safer.

You wouldn't want a person without a CS degree writing software; we shouldn't have folks without EE degrees designing power supplies.

The only problem is the fastest ADC on the market is about 200MHz. I told a vendor the systems guys needed a 1GHz and they just laughed. Now it's a running joke at work...

You obviously didn't talk to the right vendor. Maxim has had 1GHz ADC's out since at least 1997. Their fastest one right now is 1.5 GHz (MAX108). If you think about it, there's gotta be fast ADC's since there are digitizing scopes that run at several GHz.

For +12 and -12, it uses LM2587, another switching regulator, then steps the -12 down to -5. This seems like overkill to me; the efficiency gained isn't worth the extra parts.

For +12, I would use an LM1084 (powered from the car battery), which doesn't have the effeciency of a switching regulator, but doesn't require any inductors.

For -5 and -12, I would use 2 ICL662s (powered from +5 and +12, respectively), which will only supply 300mW each, but that's all we need for negative supplies.

The "typical application"s of the ICL662 and LM1084 should work fine; check out the datasheets.
National Semiconductor (LM ics)
Maxim-IC (MAX and ICL ics)

(BTW, last time I checked, coilcraft doesn't give away samples for the inductors that the website references)

Go to Maxim IC's web site, and order an evaluation kit with a couple MAX787's to deliver the 5v rail (they handle 5 amps each) and a MAX765 to handle the -12V rail. Most motherboards don't actually need -5V but if yours does the MAX764 will do nicely.

The finished circuit doesn't even get that warm with the IC's bolted to the aluminum case, even when it's delivering 80 watts.

I've tried, but Maxim IC simply will not take your money for small orders, even after you explain to them that you will never ever need 3000 of the things. You have to have them ship you the stuff as an eval kit for free. :)

Actually, I hadn't thought about 'dummy' RFID's. I'm not sure how well the multiple RFID stuff works, either, but I assume that it could be easily ironed out. Dallas semiconductor (now owned by maxim) offers one-wire memory chips, which deliver power and data over a single wire, much like multiple RFIDs working in close proximity (and actually, there is another wire for ground). Most of the time, the wire is at about 5 volts. When transmitting data, it goes down to 0 volts -- a long pulse indicates a logic 1, a shorter pulse indicates a logic 1. When data is transmitted, a capacitor built into the chips retains the memory for a power outage of up the the length of a 'logic 0' pulse.

The neat part of the one wire scheme is that every part has a unique 64-bit serial number. To access multiple devices on the bus, a simple binary search can be done... the host issues a command that it wants to search, and then starts issuing a binary number, one bit at a time. All chips that match this serial number respond... the host then can tell when it hits upon a serial number that no one responds to, and thus knows that the last bit was wrong. Eventually, all the devices are found in a fairly rapid fashion.

Non-powered RFID chips usually send data back by backscattering. The take power from a carrier wave and convert this to DC. Then, the logic inside them toggles on and off a circuit that controls the backscattering: a switchable diode in the right circuit will double (or halve?) the frequency of an incoming signal. The interigator listens for this signal.

Now, you can combine the one-wire and RFID backscatter techniques. You could modulate the carrier signal to send information (not just power) to the RFID chips. These chips would have to have a larger hold-up capacitor now that data is being sent. To receive, you'd have to send the carrier signal and listen for the backscatter. To differentiate between multiple bills, you can use the same serial-number-probe that the one-wire protocol uses.

All this is useless, of course, if you've got a tin foil-lined wallet, which I suspect will become more and more commonplace in the future...

However, Dallas (now part of Maxim-ic) has come out with a VERY cool SHA-1 based device This prevents someoen from intercepting the data sent form the iButton. It can be used as an end user device AND as a co-processor on the controller. This allows a very simple micro-controller to be used since the on board SHA-1 ibutton is used to validate the response to the challenge. When time allows I've really wanted to improve an existing design of mine for a touch & open door lock.

Note there are a number of vendors out there for iButtons - so you just might find something for Computers

However, Dallas (now part of Maxim-ic) has come out with a VERY cool SHA-1 based device This prevents someoen from intercepting the data sent form the iButton. It can be used as an end user device AND as a co-processor on the controller. This allows a very simple micro-controller to be used since the on board SHA-1 ibutton is used to validate the response to the challenge. When time allows I've really wanted to improve an existing design of mine for a touch & open door lock.

Note there are a number of vendors out there for iButtons - so you just might find something for Computers

However, Dallas (now part of Maxim-ic) has come out with a VERY cool SHA-1 based device This prevents someoen from intercepting the data sent form the iButton. It can be used as an end user device AND as a co-processor on the controller. This allows a very simple micro-controller to be used since the on board SHA-1 ibutton is used to validate the response to the challenge. When time allows I've really wanted to improve an existing design of mine for a touch & open door lock.

Note there are a number of vendors out there for iButtons - so you just might find something for Computers

However, Dallas (now part of Maxim-ic) has come out with a VERY cool SHA-1 based device This prevents someoen from intercepting the data sent form the iButton. It can be used as an end user device AND as a co-processor on the controller. This allows a very simple micro-controller to be used since the on board SHA-1 ibutton is used to validate the response to the challenge. When time allows I've really wanted to improve an existing design of mine for a touch & open door lock.

Note there are a number of vendors out there for iButtons - so you just might find something for Computers

Funny, Maxim's first app note for the MAX6512 is Simple Circuit Activates Fan When Processor Heats Up.

So it is apparently a mobo feature that uses a thermal diode integrated into the processor. Is the thermal circuit in the Pentium totally self-contained?

Funny, Maxim's first app note for the MAX6512 is Simple Circuit Activates Fan When Processor Heats Up.

So it is apparently a mobo feature that uses a thermal diode integrated into the processor. Is the thermal circuit in the Pentium totally self-contained?

I dug around on the Dallas website.. here's the press release for the TINI board, it sounds pretty interesting... is that the one you're using?

I'll have to mark it down on my list of potential fun toys to play with.

For those who obviously only skimmed my article (not the one about the lawsuit, which I am NOT a part of), please go read it again, and pay attention to the facts, not the hyperbole.

2) serial ports, as I understand them, are NOT designed to be hot-swapped safely. This is why any device that connects to a serial port (or anything other than USB for that matter) tells you specifically to turn OFF the computer before plugging it in.

That said, there is a lot of poorly-designed crap out there, and I wouldn't be at all surprised to meet a motherboard that blows itself up under perfectly acceptable conditions.

Sure, serial ports can take certain amounts of current, but obviously not as much as the ESD (electro-static discharge, yes?)

6) I'll concede that the damaged UART might have been from something OTHER than just the ESD, but the sequence of events is so apparent that anyone in the room when it happened would almost certainly agree that the ESD is what caused,

You might call me a damnass for not grounding myself, but you would agree with me about what actually happened.

I would join because I want Palm to fix a design that they KNOW facilitates damage to computers.

I fully expect even more repetitive flames from people, telling me I'm a moron, ... or anything else other than the probability that Palm decided that the risks of their cradle killing a certain percentage of people's computers didn't outweigh the cost of redesigning the cradle with it's own optical coupler to prevent ESD to the serial port.

For now, PalmV users have three choices:

With every new report of this problem, all you flamers will jump on it all over again. But, sooner or later, it will be reported enough for enough people to believe it that the problem will be fixed.

All motherboard manufacturers are under *tremendous* schedule pressures. The engineers are being pushed and pushed and pushed to get the design shipping as fast as possible. A two week delay (an ESD fix would probably take 3-4 weeks) costs the company more than a senior engineer's yearly salary, so the tendency is to say 'We zapped it, it works, what the hell let's ship it!' Keerist, with the Rambus and MTH fiascos earlier this year, Intel was shipping motherboards where *the engineers knew the digital functions didn't work*. Their priority for ESD protection was probably two notches higher than picking lint out of their belly buttons.

I guess I'm a glutton for punishment, because I'll probably come back to read what drivel you people post in reply to this message. Heck, just posting this was like painting a target on my ass for you people.

"Any available charger" - Nah. Go see Maxim for cheap silicon that controls the charge curve and shuts off the current when the battery is charged. These cost about $1. If you crack open your laptop or laptop charger, you'll find one there.

For all practical purposes, NiCd "memory effect" is a myth. Unless you're into RC car racing and can only afford the kind of charger that only has a timer.