Thread: REM Detectors (again)

http://private.addcom.de/KeithWilson/Proje...jects/hemon.htm = GOD!!!

again, it uses a PIC 16F84... but the program comes with it, you just have to program the chip (if you don't want to spend big money on a chip programmer you can build one very easily, i built mine that way... but it only works on this old 486 i have, since the power output on newer computers is not always as reliable)... but yeah, my knowledge in electronics is limited to building things from schemas and instructions, i can't create circuits... Modifying things shouldn't be THAT hard i figure.

This one has a display which is probably not necessary (so away you do with a whole bunch of components there)...

looking at this: http://circuitos.tripod.cl/schem/r100.gif measuring the heartbeat is easy as hell using the IR (again, damn those IR sensors hehe) on skin... If this is reliable, the only thing the pic does in the above schema is counting the impulses, doing some simple math and printing huge numbers on the display... which we don't need. we need the pic to do the math and flash some leds or (alternatively) start a small offcentered motor (vibrations) or whatever else. so we'd still need the pot that determines the trigger level (pulse1.gif i think it is in the zip file)...

It just got a whole lot cheaper (rather than butchering a watch, a pic costs about 3-4$ depending on where you buy it, maybe even less)... and the rest of the stuff is dirt cheap.

But I still think i'd keep the pic out and use an lpt port to begin with... i'd record BPM's over one night's sleep and then figure out how the pic would work... in my ideal case it would still be a mask, shining the IR led on the forehead, having two red leds to send the light signal and (again i go with the printer cable) one single wire connecting to a computer (i just like computers hehe)... a second version would be eliminating the computer and telling the PIC to do everything (and even record some data in its flash memory, which you could then read using the serial programmer you'd need to program the pic anyway... the problem then is the very limited data storage of the PIC and the fact the pic wouldn't just give you a nice graph of BPM's over one night's sleep the computer would AND you'd have to remove the pic --> shove it in the programmer --> download the data ---> put the pic back... which isn't really as much a problem of the time it takes as it is of breaking the pins on the chip... unless you put the serial port + programmer on the mask (or device if you still want to attach it to the hand) which wouldn't take THAT much more space, but it would increase its size, as would a vibrating motor or other signaling devices as opposed to two leds (and maybe two resistors) which are significantly smaller)

also keep in mind an LPT port eliminates the need for batteries, the circuit getting its power from the port itself

Either ways, i think this is a great start, whichever way the device is going to go

Man, i have to start learning C++ now... The only language i "know" and i've known since i was like 7 thanks to my dad is basic lol... the light machine mentioned earlier uses qbasic in my case, over a 486 laptop (which is a lot quieter at night than my P4, damn these huge processors!)

how about GSR !!!

Galvanic skin response: "The frequency of GSR and sweat rate on the dorsal side of the hand were significantly lower during REM sleep than during NREM sleep." ( http://www.ncbi.nlm.nih.gov/entrez/query.f...6&dopt=Abstract )

The "new novadreamer" by Wellness Tools (keep away from that site, again, it's complete fraud!) was supposed to use an EMG to determine skin tension, but GSR is just as good i suppose (to my understanding it's almost the same thing ??? not really sure what EMG is)

this is a simple "lie detector" which is basically a GSR: http://www.hackcanada.com/ice3/wetware/lie...or_circuit.html

and another one: http://www.hackcanada.com/ice3/wetware/lie..._circuit_2.html

The idea is the same: connect a GSR unit to a computer, gather data over a time period and build a device accordingly. using this may be a lot better than BPM's, you just attach a sensor to your finger... or, you could use both, seeing they're not that hard to build, but then you need some clever programming.

basically you just set a trimmer to a certain value, and then the gsr drops below that you turn a motor on, or a bunch of flashing leds or anything you want... the trick being adjusting the trimmer to rem (since you'd only know if it works if you're in rem)... that's why i think in order to be completely failproof you basically need to measure the difference in GSR rather than just the value (as it could be different from night to night or person to person) in which case you need the pic or the computer.

wow, i'm on fire

now i have to go take my dog to the vet i think he might be sick.

Good work, especially on finding those diagrams
How the hell did you find that? pure google?

I rule out (perhaps prematurely) GSR because it seemed like a costly route
The prices I got on pulse monitors were far cheaper

But we have quite a few options here. Nice.
I agree with your first step with the LPT port - whether we use GSR or heart rate... perhaps we should test both. It does mean more work though
Okay perhaps we test the easiest and cheapest one first (heart rate?). If it works just fine, then no need for the other

The details on where we take it from there can be tackled when we get there
We might decide to stick with wires for a while - it does uncomplicate things

As for C++, I could help you out there
I program in C++ as a profession
The electronics is the problem for me...

yeah, just googling around

pulse rate it is for now then

so most pulse monitor watches use ECG apparently, not the IR light method (which i assume is less accurate), perhaps we should look for ECG stuff.

this is where i got the schematics from: http://www.commlinx.com.au/schematics.htm there's a whole bunch of pages like that lying around the net, with the weirdest (and most useless) electronic devices imaginable... i figure building the ecg detector would decrease the cost by a lot, the only hard part being a way to change the signal from analog to digital (simple chips do that)... from there on it's just a matter of having either a serial or an lpt port read the impulses and generate the graphs or whatever.

and it's good that you're a programmer do you have experience with peripherals? i know the lpt has the 8 data pins that basically have 1, 2, 4, 8, 16, 32, 64, 128 and 256 values, and by combining the pin values you can get the computer to read basically any numeric value you want to send to it, but i was wondering if there wouldn't be a "steady" pulse/second way of using just one pin... for instance if you send 20 impulses one second and 35 the next, the software will make a time vs value graph and work from there (because in the end we don't care about the real value of the readings as much as we care about the changes in these values)...

just brainstorming.

i'll try to figure out if there's a cheap way of building an ECG monitor that uses one sensor (medical ones have tons of them on the arms and legs and chest, but those monitor a lot more things than we really need).

as for the GRS, the lie detector bit works like that. i'll try looking more into both actually, see which one is easier and cheaper to build first.

here's a good starting page (most of the links are broken though)

http://openeeg.sourceforge.net/doc/links-biopsy.html

(edited

AN UPDATE:

it seems IR led detection of pulse is far, far easier to build than ECG monitoring, and a GSR monitor as well is very easy to build (http://web.media.mit.edu/~msung/vitamon.html - if you look at the schematics on this page you'll see a very small GSR monitor that uses around 10 components or so)...

I'd leave ECG out for now, unless we butcher an ECG watch, take out the display and attach the wires connected to the display to a port and monitoring from there, which sounds very simple, but might end up in simply butchering a 40$ watch (unless we find it for cheaper).

i'm spending more time on this project than i should i think

http://arsenal.media.mit.edu/notebook/arch...ves/000209.html - it's a project for a wireless (blue tooth) GSR device... interfacing it with blue tooth technology is a whole other problem so if you leave that out for now, what you have here is a GSR device that's already converted from analog to digital and ready for port reading (i assume serial, but maybe it would work on lpt as well?)

arguments for using gsr rather than light:
1 - gsr more reliable than bpm
2- an IR light probe would require constant distance from skin, which would be hard to mentain while sleeping
3- it's easy to build this: http://arsenal.media.mit.edu/notebook/medi...a/16bit-sch.jpg is all there is to it. we could probably get the 3V from the LPT or Serial port and return the signal to the data pins. The problem now is the sensors and the placement of the sensors. Ideally i think they'd be connected close to the light or signaling device, so somewhere on the forehead... but if runs electricity through you rather than reading what's already there, you don't really want that on your face... so then i'd put it on the fingers, which creates a problem cause you'd have two wires or you'd have to give up the mask and have the light coming from somewhere else, or use a vibration signal, which could be a small motor attached to the wrist. But that's for later...

for now, the cost is a lot cheaper than a ECG watch (total cost for building the GSR unit is about 10$, including the printer or serial cable and the glasses (if you buy 1$ glasses hehe). say 15$ if you want to make it sleek and put it in a box.

so it's just a few components... i could give it a shot and see what output it gives or if it even works right.

if you have no experience with electronics, i could try building two and shipping one over.

i just HAD to... what kind of project doesn't have diagrams explaining what we're trying to get ANYWAY ?

3 different proposals for approaching the device (in it's 1st incarnation):







i like the 1st one best, but i assume there really is no difference between turning a led on or a small off-centered motor, so basically all 3 designs are the same in software design/electronic unit and the only thing that changes is the layout, which is really just a matter of putting things together.

possibly useful links:

http://www.maxim-ic.com/appnotes.cfm/appno...mber/3315/ln/en (i2c LPT port adapter software writing in C)

http://www.maxim-ic.com/appnotes.cfm/appno...ote_number/3230 (how to build the hardware)

from this point on i'll try to figure out if the above schematic for the GSR and the schematic for the LPT can work together (i'll try to get some help on this) and i guess from there on it would just be a matter of building it.

Note how it only uses 2 of the 8 data pins of the lpt port meaning we could shove in an lpt light machine at no extra cost

I've been sick the last two days ... but DUDE, you're obsessed
Not that I'm complaining, it's good progress

I prefer option 3 mainly because at the end of the day, I would idealy like a self-contained glove
Until we eliminate the wires that obviously won't happen, but I would like to find out if the vibration will actually work to trigger lucidity

If we could use bluetooth - that would be incredible
No wires, but PC operability
However as you said, either complexity or cost will increase if we do that

I'll invite my electronics loving friend around this weekend to go over the ideas, and see what he thinks
If you do manage to build a device, shipping one to me would be pretty helpful
The shipping cost would be the main factor here I guess
Our exchange rate isn't great either
Perhaps it would be easier to bribe a friend to build it for me

Once I have a device, I could experiment with the software and try fine tuning things
I'd love to see my stats on the screen

I haven't finished looking at all your links, will do so today probably
Things are pretty hectic on my side at the moment, with me being sick and transferring 2 properties at once

yeah, i've kinda been obsessing a bit
that's what happens when i actually have papers to hand in for school... i always find myself busy with ANYTHING but the school work hehe (though i did get the paper done in time).

I'll wait and see what your friend says, and I'll also go check for the availability of the components (most of which seem to be standard everyday things). It sucks that for the gsr schematic i don't have the exact part numbers, but i guess if i go to an electronics store and i say "I WANT TO BUILD THIS!" and point, they'll know better than me what i need.

And indeed, blue tooth would be amazing, it we build it and it works and we think it should go wireless, it's a pretty sweet option (it might not be THAT expensive).

Originally posted by MeusOpusMagnus
How about GSR !!!

Galvanic skin response: \"The frequency of GSR and sweat rate on the dorsal side of the hand were significantly lower during REM sleep than during NREM sleep.

I am serious here. But I almost hate to go here.
But again seriously. While dreaming both male and female have a increase blood flow to there private parts.
So you were talking skin response. I dare to say it but it would be rather simple to detect a male erection. For a female I guess you would have to go with skin temerature or GSR.
Just a thought.

Originally posted by Howetzer+--><div class='quotetop'>QUOTE(Howetzer)</div>

<!--QuoteBegin-MeusOpusMagnus

How about GSR !!!

Galvanic skin response: \"The frequency of GSR and sweat rate on the dorsal side of the hand were significantly lower during REM sleep than during NREM sleep.

I am serious here. But I almost hate to go here.
But again seriously. While dreaming both male and female have a increase blood flow to there private parts.
So you were talking skin response. I dare to say it but it would be rather simple to detect a male erection. For a female I guess you would have to go with skin temerature or GSR.
Just a thought.[/b]

true, an erection would be pretty easy to spot

but those don't signal REM as much as the fact you're asleep... more than that, they most likely happen in the morning, when the bladder expands and puts pressure of the veins (which is really why most guys will have an erection in the morning and not because of dirty dreams) so it doesn't have to do much with the fact you're dreaming.

gsr though is way easy to detect. we already have schematics for a simple gsr unit that turns the values into digital I2C AND we have an LPT port mod which is supposed to take the I2C digital value and send it to the computer... the only thing i'm worried about is how well these will link up together. Picking up the skin response is as easy as metalic foil wrapped around the fingers with wires going out, so there's no problem with the sensors add a bit of velcro and you're going hi-tech hehe

yeah, i think we're under 15$ with the cost

say, one day when we're that much wiser and richer, we turn this into the ideal blue-tooth-usb driver wireless mask... the cost would still be under 80$, perhaps even less (a usb blue tooth connector is about 40$ and for the mask to send the signal you need a blue tooth chip, an antenna (which is really just a wire) and a bunch of smaller components... but then (from what i've seen) you'd need a 9V battery, which is kinda bulky).

either ways... it proves that connecting a gsr unit to a computer costs about 15$ instead of 900$ they charge for a medical device... sure, the medical device might be more precise, but not 800$ worth of precision...

Originally posted by MeusOpusMagnus
true, an erection would be pretty easy to spot Wink

but those don't signal REM as much as the fact you're asleep... more than that, they most likely happen in the morning, when the bladder expands and puts pressure of the veins (which is really why most guys will have an erection in the morning and not because of dirty dreams) so it doesn't have to do much with the fact you're dreaming.

This is out of Exploring The World OF Lucid Dreaming. Chapter 7 (Adventure and Exploration)

"As you woulld expect in a land of complete freedom, sex is a very common theme in many people's dreams. "
"There are both psychological and physiological reasons why the lucid dreaming state tends to be a hotbed of sexual activity. In terms of physiology, our research at Stanford has established that lucid dreaming accurs during a highly active phase of REM sleep, associated, as a result, with increased vaginal blood flow or penile erections. These physiological factors coupled with the fact that are freed from all social restraint ought to make lucid dream sex a frequent experiance.

Maybe more information than you care to here but for the sake of research I wake up with an erection after dreaming.

after doing a bit more research i realize you're right. erections do indeed occur during rem sleep and the reason people wake up with them is not (as i said) bladder expansion as much as the fact they wake up from (or close to) an REM period.

but i guess there's no fundamental difference in having a probe attached to your finger or having one attached to your penis. i think it would become more complicated (and potentially more uncomfortable) for females though. Yeah, i dunno... mesuring blood flow would probably be as easy as the IR reflectivity of the skin? maybe temperature would rise ? (though i don't know if the difference in temperature would be accurate enough for REM detection). I'm also not sure how many would be willing to attach a probe to their private parts when going to sleep (ESPECIALLY if you're sharing the bed with your girlfriend, boyfriend, wife, etc)... Speaking for myself here, but i think i'd be a bit embarassed It's even worse for teenager oieronauts or even parents.

but yeah, i'm just as convinced now that erections would probably be a good way of detecting REM... it's just... strange a bit when you're not in a lab setting.

as for the GSR, i got all the parts e(xcept for two from the gsr amplifier, which i couldn't find and i'm looking for alternatives) for 35$ canadian... This includes 8$ for 2 boxes to house the projects (which really are just fo' sho' and overly priced) and WAY TOO EXPENSIVE resistors (1,20$/pack of 4 instead of 20c per pack of 5 that i usually pay)... I was just a bit lazy in shopping around and the place i usually go to didn't have everything i wanted. I wrote to the guy who designed the GSR amp i'm trying to build, asking for a few hints and I'll talk to my dad tonight (he's into electronics) to see if he can help me out a bit.

This should be fun

Placebo, if i get them built before you ger a chance to, i'll ship one over. I don't think the shipping will be that much and I'm willing to cover the costs, given that you'd have to spend some serious time doing the programming.

More progress:

I just ordered samples of the ADS1110 from Texas Instruments. For the other missing part I contacted Carson Reynolds and he told me I could use a zener diode instead, or anything that regulates the voltage to 2.5V. So i'll figure out what's easier and cheaper and get that going.

Anyway, TI estimated shipment by Sunday so I hope by the end of next week I'll be able to start work on the GSR amplifier. For now i have everything i need for the LPT connector, and I'm starting work on 2 of them.



Any ideas for the name we're giving to this baby?

(edited: actually, TI just shipped the 4 A/D Converters just a few hours ago, and they meant i'd GET THEM by Sunday, which is way way cool. Maybe by the end of next week I could ship Placebo a completed copy of the device and see if he can come up with something)

Originally posted by Kaniaz
Novadreamer two. Half the price, no fuctionality!

(Okay, I just couldn't resist having a bash. )

as things are right now, for about 20$ you could get:

- Continuous GRS computer monitoring for REM detection
- REM Signal Light/Sound/Vibration (Sound by computer, light/vibration on the body)
- Biofeedback (from the GSR) for a light machine - probably different pitch in noise
- 3 LED/eye light machine (6 of the LPT pins are spare)

Match this up to open source software already out there (like the linux version of bwgen) and you can shove a sound machine in there with no extra programming.
sounds more like the pumped up version of the dream maker wellness tools wants to sell for 1000$ + the GSR biofeedback unit you can buy for 50-60$

I dunno, if this really works we'll have a VERY NICE toy on our hands.

and, for another update: the first LPT interface is done. I'm going to give it a run now (if it works without having any I2C imput) and I'll post the results whenever they're good hehe. Took a while to make, but it's looking good so far.

hehe are you going to edit my post now too ?

Any ideas for the name we're giving to this baby?[/b]

Assuming we stuck to the hands, and not the mask, I was going to call it the DreamCatcher glove
I thought it had a nice ring to it

And dude, you're going way faster than I have the ability to. I just got over a bout of sickness, and my work is overloaded
I'm still going to speak to my friend about the electronics, for ideas
But by that time, you'll probably already have a good idea of a layout...

And yeah, this toy would be nice and extendible and damn useful for a variety of things
We could try make the mask optional, and have binaural beat technology in there as well as the glove motor

DreamCatcher works with anything though, it's a good name It could be "DreamCatcher Glove" or "DreamCatcher Mask" since as i said, the difference between one and the other is simply connecting a motor instead of leds (maybe a few extra components but nothing seriously complicated). But it's true with both the leds and the motor it would be even nicer. Given that we have 6 LPT data pins free, we could use one for the motor and 4 for the leds (2/eye). We'd have the mask and the glove use different wires, so that you could have either one or the other or both on at a time. If you're just going for the biofeedback there's no problem having the wires since you won't be sleeping with them on for 8 hours.

As for going way fast... no worries, process has been CONSIDERABLY slowed down by... you guessed it... hardware debugging. Something's not connected right and i should have thought better about it before I made it so small (it's not as small as the penny size one, i'm using regular components rather than those real tiny ones that come on rolls, but it's still small for clumsy fingers like mine.)

Anyways, it'll take a while before it's done. If your buddy drops by, this is what i'm trying to make (there are perhaps parts that can be taken out, or simplified, etc):

http://hybrid.concordia.ca/~victord/design.bmp
(forgot to mention, it's powered by 3V (i'm using 2AAA))

I also shoved in the optional LED on the LPT connector, mostly for testing purposes, if i get the led to go on and off i know i got it working and for now it doesn't work.

And good luck with your work load! As i said, it'll go a lot slower from now on.

Hey Meus

My friend dropped by and said he is quite out of practice with electronics
Nevertheless he reckons that you could simplify your circuit quite a bit

I have a few questions myself on it:
1) What kind of streaming/frequency is going to be outputted to the 2 pins on the port? What would I be reading exactly, and how fast?
2) We couldn't quite make sense of that bit of the diagram between the A to D converter and the parallel port. What does it do exactly?

The difficulty with GSR might not be in the sensors, but rather in the nature of the data.
With heart rate we can get a relatively slow pulse, which is easy enough to push through to one pin
With GSR... it is an analog stream that would need to either be converted to a frequency pulse or written to the 2 port pins in several separate steps (more complication?)
Hence my question above on what you are actually sending to the port from the GSR digital signal

Since you're using GSR, perhaps I could convince my friend to help me rig up a heart rate monitor to my PC on this side. One complication is that my PC isn't in my bedroom.
The circuit in HeMon for that is pretty cheap and easy to build, and I reckon I could manage it on some veraboard and wires
The more difficult bit for me is perhaps to do the writing to the PC port

My friend also reckons that the serial port is a lot neater and easier to use, especially on the software side
Have you considered it? What are our reasons for the parallel port again?

Regarding using the device for 8 hours sleep... this is important to me to be able to do it
I would like to be able to analyse the data of a person's sleep cycles over an entire night
And possibly glean some information on my own sleep patterns based on various factors, etc
Perhaps the wires on my finger won't be such a problem ...



Thanks for the hard work so far

I'll try to touch on all the points.


1) What kind of streaming/frequency is going to be outputted to the 2 pins on the port? What would I be reading exactly, and how fast?

I don't know exactly what kind of numbers the output will be. I know the I2C has a clock line and a data line and it sends (and recieves) 16 bit info.
http://www.maxim-ic.com/appnotes.cfm/appno...mber/3315/ln/en - this page has all the info + C files already made to just include in the programming. Either ways, I2C is a VERY common technology, so i'm sure figuring this out won't be hard (the hardware debugging software i got shows the imput it's getting, so we can toy around with it and figure out how it works, because I'm sure you can get it to just use an echo command, where you send an impluse and it replies with the value it's currently at.
LPT ports are very fast, so that shouldn't be a concern.

2) We couldn't quite make sense of that bit of the diagram between the A to D converter and the parallel port. What does it do exactly?

You mean the dotted lines ? It just links the GSR amplifier to the parallel port "translator". The parallel port circuit is basically one 74H05 chip with a bunch of resistors, it's just meant to transform the signal from I2C to LPT language (hex).

3) The relatively slow pulse/vs incoming flow of information:

Well, with a continuous flow, you could have the biofeedback be continuous if it ever were to be implemented. Dealing with it for rem detection wouldn't be too hard, you could just take one sample every x seconds and build a graph.
It's not an analog stream anymore, because the ADS converts it to digital and the second little unit converts it to printer port impulse.

4) the HeMon circuit is indeed cheap and easy to build but there are a few considerable problems with that: because the difference in heartrate between regular sleep and REM sleep is not very significant you'd have to be very precise in monitoring the heartrate, which would imply the same as any other REM IR sensor, and that's having a constant distance from the skin to the sensor, which might be a little tough when you're sleeping. It might work nonetheless, but then with the distance between sensor and skin and the size of the led and photosensor you'd have about an inch of stuff going up from your hand, which would have to be hardmounted to keep the distance the same... So it gets a little tricky if you want a glove.

5) Serial is indeed easier to use, but it won't allow for as much development as LPT would... You'd be stuck with the number of pins and if you'd want a light machine or something else, you'd have a hard time integrating that without more circuitry, whereas the lpt you have 8 separate data pins that you can control as you please. So the advantages of the LPT port are really in the versatility it offers, we can expand a lot more having that.

6) The way the device will take shape (right now) is a small box which will have a bunch of wires coming out. What I'll do is I'll stick the port straight to the case so that you can use a male-female lpt cable as long as you want to do the readings. Then you can put the box wherever. From the box, you'll have the wires for the probes coming out and a number of leds (that won't be mounted, to save on shipping space). Those you can either mount yourself, or (i'll have them number) just pretend they're mounted. You don't have to worry about the leds or the motor for the time being, we'll just go for the reading. But basically you'd turn on a motor the same way you'd turn on the led (and i'll have to check for small motors or stuff like that and how to connect those with the circuit)... So if you can turn on one led, you can just replace it with a motor in the end... for starters you'd basically just have one wire going to your hand.

and for some extra news from TI, i got my chips yesterday at 10 (they took less than a day to deliver, i was really shocked hehe). This is our first problem because they're just SO DAMN SMALL heheh, i'll have to figure out a way to mount them nicely on a regular board. At the same time, it's absolutely great, because the entire box could be reduced to really not much if we wanted to make it computer-free... but i'm really attracted to the computer idea, it seems like a great way to record data (if we make this open source and we get software help from numerous other people, this could develop in a very nice research tool)... if it works right, of course.

I'm still debugging the printer connector (no worries, if that one's messed up i have parts to build 6 more hehe) I'm thinking it might be something that has to do with windows XP, because i can read and write from it, i just don't get the right values and the software they provide just crashes. So I'll try to figure that one out and as soon as i'm done with those i'm starting work on the GSR...

I'll probably get some help to test the GSR with the oscilloscope and then i'll stick it to the printer port and see what that reads.

but you can certainly build a heart monitor and see how that reads out. You'd still need an analog to digital converter and those usually spit info out in I2C (from what i learned lately) so you might still have to figure out a way to resolve the computer connectivity issue.
If you use a watch and you butcher that up it might be as easy as connecting the wires that go to the display to the printer pins of the printer port or serial port, but i'm not very sure about connectivity issues there (you might need some extra parts and i wouldn't know much about those).

i also thought the GSR was good because unlike the other gsr schematics out there, this one's self calibrating, so you don't have to waste time every night with a skrew driver trying to calibrate your unit and then worry it might change during the night.

it would actually be nice to have someone who REALLY knows electronics on the team, then we'd have a much easier time... there are things that just go way past me and i can copy them, but i can't explain them... When i'm in trouble i just go to my dad and he helps sometimes (he's in electronics) but he's a busy guy. But i have a good feeling about this, i think it's going to work nice.

I don't know exactly what kind of numbers the output will be. I know the I2C has a clock line and a data line and it sends (and recieves) 16 bit info.

Alright, that makes sense. The link to the C++ examples will help a lot too and the fact that it is common technology...
The programming side of things is probably the least of our problems anyway - I'm pretty capable in that area

because I'm sure you can get it to just use an echo command, where you send an impluse and it replies with the value it's currently at.
LPT ports are very fast, so that shouldn't be a concern.

Perhaps that can work
The speed of the LPT shouldn't be a problem, no. It was more a concern with the streaming, realtime GSR information on a parallel port
The parallel port doesn't support event notifications/callbacks I don't think

You mean the dotted lines ? It just links the GSR amplifier to the parallel port \"translator\". The parallel port circuit is basically one 74H05 chip with a bunch of resistors, it's just meant to transform the signal from I2C to LPT language (hex).

We figured it had something to do with conversion to the LPT in some form
So basically it uses hex, and a clock/data system to stream it in 2 bit 'packets'
Sounds complicated for electronics, but if that works.... we can always revise our decisions later since this is essentially prototyping

you could just take one sample every x seconds and build a graph.
It's not an analog stream anymore, because the ADS converts it to digital and the second little unit converts it to printer port impulse.

Fair enough

but then with the distance between sensor and skin and the size of the led and photosensor you'd have about an inch of stuff going up from your hand, which would have to be hardmounted to keep the distance the same... So it gets a little tricky if you want a glove.

I've seen monitors that use clamps on fingers or ears
Perhaps we could use the same mechanism to keep the distance?

I have higher hopes for GSR anyway, but I might still play around if I can get the time

So the advantages of the LPT port are really in the versatility it offers, we can expand a lot more having that.

Alright, fair enough. One concern I still have is with drivers or software to read the parallel port effectively. Eg. see the trouble you're having on XP

The way the device will take shape (right now) is ..

Yeah, I understood you to mean all that anyway
That's fair enough for the time being

and for some extra news from TI, i got my chips yesterday at 10 (they took less than a day to deliver, i was really shocked hehe). This is our first problem because they're just SO DAMN SMALL heheh, i'll have to figure out a way to mount them nicely on a regular board. At the same time, it's absolutely great, because the entire box could be reduced to really not much if we wanted to make it computer-free...

Sounds good
And good luck
Amazing delivery time...

but i'm really attracted to the computer idea, it seems like a great way to record data (if we make this open source and we get software help from numerous other people, this could develop in a very nice research tool)... if it works right, of course.

I like the idea of processing information on the computer. But I don't like the idea of wires
The perfect compromise would be wireless communications
But that's pricey and complicated

I was considering the possibility of cellphones
Either USB data cables to a cellphone for data recording onto a MMC card, or preferably wireless comms with something like bluetooth (read: again, complexity and cost )
It probably won't happen, but it's a nifty idea anyway

but you can certainly build a heart monitor and see how that reads out. You'd still need an analog to digital converter and those usually spit info out in I2C (from what i learned lately) so you might still have to figure out a way to resolve the computer connectivity issue.

I'm toying with the idea... if I can get the time and help from someone else with electronics knowledge ...

If you use a watch and you butcher that up ...

I looked around, but that's a very pricey option. Perhaps it's just my area, but I can't find a cheap watch with heart rate monitor attached

i also thought the GSR was good because unlike the other gsr schematics out there, this one's self calibrating

Good point
And I have greater hope in GSR as our winner

it would actually be nice to have someone who REALLY knows electronics on the team, then we'd have a much easier time...

Indeed

When i'm in trouble i just go to my dad and he helps sometimes (he's in electronics) but he's a busy guy. But i have a good feeling about this, i think it's going to work nice.

Well at least your dad can help on the odd occasion
And I think it will eventually work. Hopefully without wasting too many components.
I can't wait to actually get some use out of it

yeah, i'm a bit worried about windows XP as well... i rebuilt another lpt port connector and i have the same problem as before (the software given just crashes). I'll try reading up a little more, see if i can figure things out, but i think it has something to do with 2 resistors that end up being placed in parallel (if you follow the design given)... i'll send them an e-mail soon.

you can also buy one of these lpt port thingies for 150$ they have a few extra memory parts, but yeah... 150$!!!

new development



this is what it looks like so far. Tonight i'll start work on the second one because the LPT connector works fine... it's XP that was the problem. I ran the program in windows 98 compatibility and it didn't crash anymore, it started to perform the test and then said failed... So i installed win 98 on another machine i have (an old 486) and it worked just fine, the tests were good, the led went on and off.

there are ways to make it work in xp, there is a driver for that might fix the problem (for another type of lpt communication device) and it's very minimal... it won't change anything, it's just going to take down the paranoid protective measurments XP uses on communication ports, which isn't there in other systems (well, the driver just acts on the LPT port, not on all ports)....

So i'll try figuring out what's going on and if there's a way to easily go around it... if not i have a few buddies who might be able to help (one of them was writing drivers in C a while back, he could probably write a small transparent driver in no time if this one doesn't do the trick). i'll figure it out whenever i get a bit more time and i'll let you know what's happening.

I've not been following this, so forgive me if this is a stupid suggestion. Have you guys thought of using the RTS line on COM1 to get the data in? I've used this approach in the past.

If I am remembering correctly, it is simple to monitor both this pin and DSR as well.