Coding SD Memory Cards

[crashsite]

I know I'll take some flak for this approach but, thought I'd try the "eaasy" route first and just ask here in case anyone knows...

I have several projects mulling around that seem to end up needing some data stored in non-volatile digital memory and it seems like a fairly simple and practical resolution is to use a flash memory module like the SD card.

Are there users here who have "figured" this out and have the basic knowledge to share? That is, the pinouts for the contacts, the required voltages and currents for programming the card and reading the data, timing diagrams for read/write cycles, etc.

I guess I should also note that the desired method is to manually (or semi-automatically) program the card rather than interface it to a Pentium or PIC or some other involved process. Case in point:

One project is to make a home entertainment center remote control for sight impaired people. The idea is large, well-lighted buttins and the ability for non0technical users to be able to program it. The idea for programming is to save the code produced by the factory-supplied remote for the equipment (TV, VCR, DVD, amplifier, etc.) in the oversized remote. Programming would involve setting the big remote to the program mode and then pressing the buttons while simultaneously pressing the corresponding button on the "factory" remote to program the code (which would be stored on the SD card). Once programmed, the big remote would be set for normal operation and the buttons on it would do the work.

I'm also thinking about an altimeter with only one moving part (a bellows which would directly drive a digitizer). The device would also have a temperature sensor. The programming would simply involve subjecting the altimeter to a "programmed" sequence or pressures and temperatures while measuring and saving the output data. Thus, the altimeter would need no "calibration", just the abiltiy to repeat the same digital code for the same temperature/pressure conditions with the data on the flash memory doing the correction to acutal altitude (code conversion). Of couse, there would still be the need for setting the current barametric presssure correction but, that's another issue.

And, the list of projects that can use a simple SD card programmer go on and on and on....

 

[karenhornby]

"One project is to make a home entertainment center remote control for sight impaired people. The idea is large, well-lighted buttins and the ability for non0technical users to be able to program it. The idea for programming is to save the code produced by the factory-supplied remote for the equipment (TV, VCR, DVD, amplifier, etc.) in the oversized remote. Programming would involve setting the big remote to the program mode and then pressing the buttons while simultaneously pressing the corresponding button on the "factory" remote to program the code (which would be stored on the SD card). Once programmed, the big remote would be set for normal operation and the buttons on it would do the work."


WHY????
You can already buy this VERY CHEAPLY, its called a universal programmable remote control, or if you want one already programmed, its a "universal remote"

 

[Super_voip]

it's possible to have altimeters with no moving parts which are reasonably accurate.As the barometric pressure from the atmosphere changes there will always be a minor variation.
As for the SD card, there are so many references to it and connection to microcontrollers, PIC 8051, take your pick.
As for the size I have a novelty TV remote as you mentioned about the size of two A4 pages, yes it does a couple of remotes Price $10

 

[crashsite]

Yes, I have some of these remotes and, have used more than just a few over the years. They come with multiple problems for the sight impaired. They don't have big buttons with half inch tall caracters or brightly lit buttons or individual keypads for each device. They program from a sheet or book that's a "catch-all" with rows and columns of tiny text and, frankly, are not very "user friendly" to program...assuming you manage to find your device (especially if it's an off-brand like a cheap sob, like myselft, tends to buy). Even if you buy very "white bread", name brand stuff, it's often difficult to find your exact model and you need to try different alternatives to get the remote to work (and, that's with normal eyesight...imagine when you can't even read the codes). The universal remotes tend to have lots and lots of buttons (to help make them "universal") and that makes it difficult for sight impaired people to memorize the functions. Most of the time the basic functiona are used and the big remote would cater to those while still allowing the "factory" remote to be used, if needed, for the specialized or seldom-used functions.

As a person who probably has normal sight, none of that likely makes much sense to you but, if you ever do lose even partial sight, trust me...this will all become amazingly clear.

BTW: You are right..."cheap" is an understatement since I have even bought universal remotes brand new at the Dollar Tree and guess for how much...

 

[crashsite]

As the barometric pressure from the atmosphere changes there will always be a minor variation.

As for the SD card, there are so many references to it and connection to microcontrollers, PIC 8051, take your pick.

As for the size I have a novelty TV remote as you mentioned about the size of two A4 pages, yes it does a couple of remotes Price $10

Per the altimeter, yes. At the present state of technology as you fly there will always be un-accounted for barometric variations (the old pilots' adage, "Flying into a low, look out below" still very much applies). I expect that cheap radar altimetersand improved vertical resolution for GPS for light planes and satellite commpunications from weather services which will sense and send these variations to aircraft, on a "local" basis will become reality. But, it's still a ways off.

About the novelty remote. Of course it's very easy to "size up" a remote control. Any high school electronics student can do it since it just involves bridging SPST pushbutton switches across the contacts in a regular remote and adding big buttons. But, that doesn't address the programming aspects or the need for lighting.

Thank you for pointing out that there's a lot of info on the SD card. I wouldn't have guessed had I not asked about them here (geez, I wass hoping that my original lead-in would have given me data rather than a scolding). Ah well...

 

[crashsite]

PICs and Computers

I thought I could get away with avoiding the PIC and computer discussion but, they are already popping up in responses. I had avoided telling about how I got the idea for this remote programming in the first place but.....well, here goes.

Years ago, I bought a really slick little video editor (Years ago as in when computer, non-linear editing was super expensive and even industrial editing was still often done with VCR decks, sometimes with computer assist). Anyway, this unit allowed you to record your remote button presses (play, record, FF and rewind only) with the notion that your play and record VCRs could repeat the sequence later accurately enough for home editing. Of course, the whole editing scheme was pretty iffy but, the fact that you could point your remote at the sensor in the box and record the remote commands was pretty impressive.

Two things to note. The box did not require a computer interface (or physical connections to the VCRs) and it didn't require computer programming expertise. "My" sight impaired remote is a simpler solution than the editor so, I'm pretty sure no computer or PIC needs to be involved.

 

[Nigel Goodwin]

Two things to note. The box did not require a computer interface (or physical connections to the VCRs) and it didn't require computer programming expertise. "My" sight impaired remote is a simpler solution than the editor so, I'm pretty sure no computer or PIC needs to be involved.

And you would almost certainly be wrong!

It's pretty well certain that the recording device used a processor, PIC or some other type, a purely hardware solution would be much too expensive and complicated.

Learning remotes are cheap and commonplace, just buy one, strip the insides out, and rebuild it as a large remote.

 

[crashsite]

Did it really need computing power?

And you would almost certainly be wrong!

Learning remotes are cheap and commonplace, just buy one, strip the insides out, and rebuild it as a large remote.

I never opened the box but, it may or may not have used a processor. There was a two step process. First, you saved the remote coding (which you had ot do each time you powered up) and then you did the editing function. I envisioned a piece of memory that remembered the remote codes (recall that there were very few) and then the rest was just timing (similar to the record function you might have seen on a music keyboard of the day) for the editor funtion. The box had the IR sensor for recording and the IR emitter for controlling the VCRs. The editor then just needed to spit out the right remote codes at the right time marks to effect the edits. I think you can probably envision this being fairly easily implemented without a processor (or with).

Per the remote. If the goal is to "copy" the remote button presses into a memory I think it might be counter-productive to try to modify an existing universal remote because then you still have all the problems associated with that remote for sight impaired folks. By "home programming" with the factory remote, only the functions needed would be programmed, the same big remote could be continue to be used when equipment gets changed by just reprogramming with the factory remote that comes with the new equipment.

I'm not saying that your "method" is impractical or that it might not be more "cost effective". But, I think it has drawbacks that are easy to overcome with a fresh, ground-up design.

 

[crashsite]

No moving parts?

it's possible to have altimeters with no moving parts

I apologize. I missed this in my first response to your post.

Uhm....HOW do you make an altimeter with NO moving parts. Theoretically, there are ways but, I'd be interested in your approach to make a practical one.

 

[Nigel Goodwin]

Per the remote. If the goal is to "copy" the remote button presses into a memory I think it might be counter-productive to try to modify an existing universal remote because then you still have all the problems associated with that remote for sight impaired folks. By "home programming" with the factory remote, only the functions needed would be programmed, the same big remote could be continue to be used when equipment gets changed by just reprogramming with the factory remote that comes with the new equipment.

I'm not saying that your "method" is impractical or that it might not be more "cost effective". But, I think it has drawbacks that are easy to overcome with a fresh, ground-up design.

A learning remote already does exactly what you want, it stores the button presses from another remote control, and allows you to play them back - all you need to do is put the insides out of one in a bigger box with larger buttons and switches.

 

[blueroomelectronics]

They already have monstrous remotes. Lighting them would just gobble up the batteries.
**broken link removed**

 

[crashsite]

They already have monstrous remotes. Lighting them would just gobble up the batteries.

I guess it's not surprising that people would already be thinking along the remote control ideas (initially presented as just one possible use for the need to program SD flash memory chips). Regarding the lighting, LEDs don't consume too much power and big remotes can accept big batteries. Also, powered docking to place the remote in for recharge is not unreasonable.

At one time I was planning a "working" wall mural that was a huge telephone dial (about 2M square) with a "tiny" regular size hookswitch and handset on the side.

As far as the SD chip tech details are concerned, I guess the "response" to my post is an implied, "get off your lazy arse and go figure it out for yourself, young feller".

 

[blueroomelectronics]

The SD card only adds a level of complexity. USB on the remote is how it's done, look at the Logitech / Harmony remotes.
I would think different shaped buttons would be a better solution than lit buttons, no power requirement and most people that use remotes don't look at them after they learn where the buttons are.

 

[crashsite]

The SD card only adds a level of complexity. USB on the remote is how it's done, look at the Logitech / Harmony remotes.

I would think different shaped buttons would be a better solution than lit buttons, no power requirement and most people that use remotes don't look at them after they learn where the buttons are.

Well, USB implies a USB capable device. I thought that coming up with a general-purpose SD card programmer could solve a lot of the simpler situations while providing a cheap source of memory and the ability to change out memory in devices or applications that require it. I'm not absolutely convinced that a computer or even a PIC is necessary to either program or use it (perhaps that's just my ignorance speaking but, if it's just memory, there should be a multitude of ways to write to it and read from it).

Hmmmm...I wonder if there's a nice compact tutorial on the web about using SD cards (similar to some of the URLs to PIC tutorials posted on this site)

I agree with your comment about thebuttons on a remote. I think there's a lot that can be done both with button shape and spacing that can make the remote more "tactile" and that's for all cases, not just for sight impaired people. I know I have remotes that are not easy to use by touch.

 

[blueroomelectronics]

Most SD card readers are USB. I've never seen a serial based one and it would be dirt slow.
SD cards also work with blocks of memory, you really do need some form of computer / micro to use it.

 

[crashsite]

The SD Card Laid Naked

Most SD card readers are USB. I've never seen a serial based one and it would be dirt slow.

SD cards also work with blocks of memory, you really do need some form of computer / micro to use it.

Now, see. We're now getting to the sorts of responses I was hoping for in my initial post.

Yes, most SD card readers are USB but, that's because USB is the main defacto standard peripheral device interface these days for computers. But, who sez ya gotta use a computer at all to use an SD card. BTW: Did I miss something when I read what the "S" in USB stands for?

Often speed is just not an issue but, I'm not sure why an SD card would be inherently slow if it isn't used with a USB device. You should be able to read and write from/to it as fast as you can address it (within the timing limits of the card...or so I would surmise) regardless of the electronics used.

Regarding the arrangement of data in the memory, that's exactly the sorts ot things I was hoping to glean. Is the memory arranged like a hard drive? Is it possible to put 1 byte into an SD card without using up 1 kB (or whatever the block size is)? But, even if there is a block structure and you know the block boundaries, it still should be pretty easy to address the card without resorting to computing stuff.

An ancilary question might be whether the blocks are even "real". Are they created during a format so the card can properly emulate a disk drive for the edification of the host computer? If an application does not use a computer, is there even a requirement to "format" the card at all or can you use it as just a big, inexpensive 8 X whatever memory chip?

There seems to be a prevalent feeling these days (which seems to run pretty rampant on this site) that any time you want to turn a 1 into a 0 you need to use a PIC and a memory chip and write a program to do it. Sometimes you just need to stick an inverter into the circuit and be done with it.

 

[blueroomelectronics]

Serial ports (the RS232 kind) are disappearing fast on PCs and are long gone on Macs. They are still popular with microcontrollers as is RS485.
You want to use a memory device but sans a CPU, that doesn't make much sense to me.

 

[Nigel Goodwin]

Well, USB implies a USB capable device. I thought that coming up with a general-purpose SD card programmer could solve a lot of the simpler situations while providing a cheap source of memory and the ability to change out memory in devices or applications that require it. I'm not absolutely convinced that a computer or even a PIC is necessary to either program or use it (perhaps that's just my ignorance speaking but, if it's just memory, there should be a multitude of ways to write to it and read from it).

You might not be convinced, and you're not 100% wrong - it would be possible, but not at all practical - essentially you would be building a hardware programmed computer from scratch. It's really such a silly idea!.

 

[Super_voip]

I apologize. I missed this in my first response to your post.

Uhm....HOW do you make an altimeter with NO moving parts. Theoretically, there are ways but, I'd be interested in your approach to make a practical one.

Here is the first site from google, **broken link removed**

 

[tytower]

Most SD card readers are USB. I've never seen a serial based one and it would be dirt slow.
SD cards also work with blocks of memory, you really do need some form of computer / micro to use it.

I thought usb was a serial device ? It has 4 connections ,2 power and 2 data being D+ and D- . One is usb to device other is device to usb but the signal is serial on either data line no?