Preinstall an SD card?

[chipaudette]

Depending on what we decide for the enclosure, do we preinstall an SD card in the ASA units?

[biomurph]

Yes, depending.
I would prefer not to have to add an SD card to the BOM, but it would ensure that they get a good, fast card.

Would these cards be a good candidate? They don't seem to have any speed certification, but they are cheap... you do get what you pay for...

[chipaudette]

For recording audio, the Tympan RevD has been extremely sensitive to the card that one uses. I can't speak to SD on the RevE.

For the RevD, we've used SanDisk Ultra 32GB. Chris found these. None of the other SD cards gave nearly as good performance. Once he found them and we saw that they were so much better in our system, it's the only thing that we would use.

Recently, we had a hard time getting the Ultra, so we bought some SanDisk Extreme 32GB. We hope that they are as good as the Ultra, but we don't know for sure. Anecdotally, Chris has not had quite as good an experience using the Extreme, but the underlying SD library has also been changing, so it's hard to know what's really at fault.

We should not use the cheapest cards as everyone will just be disappointed with the inability to write audio without hiccups showing up every few seconds.

Right now, I'm not proposing that we pre-install SD cards long-term into all Tympan RevEs. I'm only proposing that we do it for the ASA units. For ASA, I vote that we use the best cards that we know about. We can buy them.

[biomurph]

@chipaudette I agree that we should use the best, and that the low cost ones can be glitchy.
In my experience, I use lower level mcu that do not run native SD (they use and SPI hack). Those systems definitely need high quality SD cards. Now I know that the Teensy (and Tympan) do as well.

It would be a nice perk to add the SD card to the ASA kit. I will look for the ScanDisk Ultra.

[biomurph]

I've sourced the ScanDisk Ultra 32GB

[chipaudette]

Thanks Joel. When I said "We can buy them", I meant "Creare can buy them". Upon re-reading, that wasn't clear. Sorry. If you would prefer that Creare buy them, let me know.

[biomurph]

I'll email you a link to the cards.