What did you do in your shop today?

I think that some of these cheap SD cards have failed the manufacturers' testing process and are shipping out the back door to the grey market.

They may have started as 16GB cards but have many bad sectors. They often report the full size when something queries for the device size. But, their effective size can be much smaller.

Posted by: @robo-pi

Posted by: @triform

Oh yeah, they will read as the size sold as but really be smaller.

How do you mean?  I can see where they might have the wrong size printed on the label.  But how could they read the wrong size to the computer?   When I back up my cards I end up with a file that 15.9 something GB.   I wouldn't think that could happen if they were really only 4 or 8Gb.

I don't know though.  You might be right.  I never actually  tried to shove 16GB of actual data onto one of them and see if I could retrieve all of it.

I mean if it said 16GB on the label but when I stick it in my computer the computer only reports an 8GB card, then I could see where I got ripped.

Sorry, just saw this one. In the device in the FAT or partition table, I believe as a different size.  You can test them with tools like H2testw.

Scott

Posted by: @twobits

They may have started as 16GB cards but have many bad sectors. They often report the full size when something queries for the device size. But, their effective size can be much smaller.

This is true.  I haven't checked these cards out extensively.  I imagine a full diagnostics could be done on them.  I probably should do that with a couple of them just to be sure they are indeed working properly.   A diagnostics would report bad sectors, etc.

It is true that I haven't even come close to using the full capacity of these cards.    I think the max I've used to date is less than 4GB of actual space.    I don't use a lot of space in my projects.   In fact, on the Arduino boards I use very little space.   Probably far less than even 1GB.    I just like the idea of having an SD card for storage and access to my data.  The key thing for me personally, is that these cards are even cheaper than what I could buy a 4GB card from other sources.    So as strange as it may sound, even if they turn out to have bad sectors they are probably still a good deal for me.   But that may not be true for someone who actually needs the full capacity of the cards.

I'll try to find time to run a diagnostics on some of these and see what it turns up.

When I first bought them I wrote a file to all 10 of them, just to check to see if they were working at all.  They all recorded the file and I was able to re-open it, etc.   So at least in that regard, they all worked.  Beyond that I haven't done anymore testing on them.   All I can say is that thus far all the ones I have put into use have worked in those projects without a hitch.   But again, I'm not using the full space by far.

Posted by: @triform

You can test them with tools like H2testw.

Yes, I'll take a closer look at them when I can find the time.   I haven't really put them through any serious analysis.

The other thing too is that they might simply be slower than the class 10 they are supposed to be?

Again, that wouldn't be a problem for me.  But it could be a problem for someone who needs the class 10 speed.

Posted by: @robo-pi

Posted by: @triform

You can test them with tools like H2testw.

Yes, I'll take a closer look at them when I can find the time.   I haven't really put them through any serious analysis.

The other thing too is that they might simply be slower than the class 10 they are supposed to be?

Again, that wouldn't be a problem for me.  But it could be a problem for someone who needs the class 10 speed.

Yeah, I still use the ones I have that were maked a larger size. 

I guess this should all be placed in context and purpose.

If I had a project where I absolutely needed the dependable speed and size of and SD card, I would simply purchase more expensive cards from a known reputable source.   Better safe than sorry if you are working on a serious project. ? 

So keep in mind that I'm coming from a purely prototyping perspective, as well as one of being a home hobbyist.   Working with inferior equipment at CHEAP prices is about the only way I can do this.   The prices are often so CHEAP that it pays to get a bunch of them to just play around with.   Better to have something to prototype with than nothing. 

So that's the mindset I'm coming from.   But yeah, if you're working on a serious project where you need the full capabilities of everything you use, then by all means, buy the best stuff you can afford.

If I had some serious robot projects that were far along in terms of software, I'd start buying more expensive storage media. ? 

But right now I'm just in the prototyping stage and experimenting with a bunch of different projects.  So, for me right now, having a bunch of stuff in my parts boxes is better than just having a few high-quality items.

So yeah, if you have a serious project that is well underway, buy all means by the best parts you can afford to buy.  No point in cheaping-out on a serious project.  That would be asking for trouble.

So only buy the cheap stuff if you're looking to fill up a prototyping parts box with some parts you can grab in a pinch just to try out a new idea.  That's the world I'm currently living it.  So I tend to post ideas from that perceptive.  I should probably put some kind of note along those lines in my signature line.  Not sure how to quickly state it though without having a full explanation.

@robo-pi

Hey they are cheap, so no issues for me.  I like cheap, well for some things 🙂

Posted by: @triform

@robo-pi

Hey they are cheap, so no issues for me.  I like cheap, well for some things 🙂

Exactly my thoughts as well.  It all comes down to purpose.   If I was buying an SD card to hold the data for a self-driving car I'd buy the best card I could find from the most reputable supplier.  I'd pay out the A$$ for it and have no complaints. ? 

Not only that, but if the card failed and caused a major accident I could always sue the reputable supplier of the SD card for having sold me a faulty product. ? 

Yep, I usually buy a lot of 5 or 10 of the cheap parts. It can be cheaper than buying 2-3 of the name brand parts.

I need to assume that I will lose a few parts due to letting the smoke out on any given project.

I was on Amazon yesterday looking for a metallic silver sharpie. Most, in multiples averaged about 2 bucks each. After looking for what seemed like an hour I found 12 for 6.98. I was pretty happy about my buy so I mentioned it to the wife who says, what do you plan to do with a lifetime of metallic silver sharpies?

IT'S ABOUT THE BARGAIN! lol. 2 buck each name brand Sharpies for only 59 cents each?

I know she's right but maybe if there's some extra space in my casket she can toss them in with me.

Sharpies for the future
I'll take them to my grave
and paint a silver lining
as I learn to misbehave

I'll write upon the ceiling
and write along the side
and write my deepest secrets
as I have nothing left to hide

So, yes, I love to find a deal
cheap markers for my life!
I can even take them with me
so says my loving wife

Posted by: @robo-pi

Sharpies for the future
I'll take them to my grave
and paint a silver lining
as I learn to misbehave

I'll write upon the ceiling
and write along the side
and write my deepest secrets
as I have nothing left to hide

So, yes, I love to find a deal
cheap markers for my life!
I can even take them with me
so says my loving wife

Awww, that brought tears to my eyes. Your brain is weird, pi.... Keep it that way.

Forwarded that poem to my wife. Hopefully she'll get a laugh.

Posted by: @recycled-roadkill

Your brain is weird, pi.... Keep it that way.

It's only going to get worse.  I think there's fungi growing in there.

My shop efforts have greatly deteriorated of late. This spring, I was all about setting up a fully autonomous Arduino tomato garden. I had limited success but learned a tremendous bit about my one life's failure- gardening. Currently, I am experimenting with wild bird feeding. The challenge is to segregate the much-hated pigeons from the rest of the more loved birds, such as finches, sparrows, doves, and mocking jays. Although I am doing this rather by hand, for now. I am intrigued by the Arduino possibilities- such as sensing when the heaviest birds are attacking the feeder and reacting to that in some "Pigeon-only terrifying way". However, in conducting my research on this potential project, I have actually begun to appreciate the fine degree of intelligence in the pigeons. They seem to adapt to every countermeasure I toss at them- and do so very quickly.  However, I am also finding out doves are as dumb as mud bricks! I am amazed they are smart enough to learn how to breathe! 

Anyway, today I am supposed to go to the physical rehab center to begin the process of learning how to care for my now invalided wife who is due to come home within the week. That may open up even more intriguing Arduino project possibilities. 

@altoidian

You sure do choose the most difficult areas of automation.   All biological related areas.   So your projects include far more than just the problems of automation.   As you say, when you are up against the pigeons you are up against an intelligence system that is itself dynamically changing as you try to build an automated system around it.   The subject matter you tackle often takes others an entire lifetime of study and even after that they still find themselves struggling to deal with the problems.

Sorry to hear about your wife.  When I was taking care of my elderly mom I employed many forms of technology that was often home-built.   Many were mechanical devices, such as having to modify a walker to fit through the narrow spaces of our cottage.  Another electro-mechanical device was a crane system that included a rail system mounted on the ceiling of the bathroom (made from old bed frame angle-iron).  I built a little wheeled dolly to run along the track.  On the dolly I mounted an electric winch originally sold to be used on the front of an ATV.   And then I cut the legs off an old plastic outdoor lawn chair.   This was used so that I could prepare my mother for a bath and she could sit in the chair which I would then lift up with the winch, and roll along the track to place her over the tub and lower her into the water.   And of course, I used it after the bath to lift her back out again.   No Arduino needed, but still an application of technology.

The other thing I did was buy a set of walkie-talkies so I could leave one with my mom and take the other one with me.  This freed me up a bit to be able to go outside and chop firewood or do whatever other chores I had to do without having to leave mom "unattended".   At least not entirely unattended.   And that did work quite well because she was able to call me in if she had to go to the bathroom or whatever.   I was fortunately able to find walkie-talkies that had a quite loud CALL button.   So my mom could just press the CALL button and I would hear the loud buzzer even as I chopped firewood, etc.   Plus I could always call her to check-in that everything was ok too. 

Anyway, best of luck in your automation projects.