I recall watching a documentary (on Curiosity Stream maybe? I’m no longer subscribed) on data storage longevity. It covered DNA storage, which I think this PBS video w/ transcript provides more recent coverage of its developments. As well as holographic storage, which I could only find the Wikipedia page for.
As for which one I think might be the future, it’s tough to say. Tape is pretty good and cheap but slow for offline storage. Archival media will probably end up all being offline storage, although I could see a case for holographic/optical storage being near line. Future online storage will probably remain a tough pickle: cheap, plentiful, fast; select at most two, maybe.
Setting aside whether the California flag needs a wholesale overhaul or just have the words removed, the Canadian pale tricolor here is an interesting concept. What’s irking me the most is the bridge, which is very prominent on this flag, but there’s enough missing from the rendition that it bears almost no similarity to the most famous bridge in California.
The Golden Gate Bridge has towers in an Art Deco style. I’m not an art student, so I can’t really describe what makes it Art Deco, but the prominent detail are the flutes which extend up alongside the tower, tapering off. From the side, it would make the tower somewhat blockish. Often times, a stand-in for the GGB is the Guy West Bridge in Sacramento, which is a smaller suspension bridge and has no Art Deco flares.
The other issue is the number of cross arms. Both the GGB and Guy West have four evenly-spaced cross arms, whereas here there are only two, with a large space where a third one should be but isn’t.
Please don’t take this as a personal dig at this rendition, but California is not particularly known for bridges generically – although our other, less famous bridges are becoming infamous – but instead for one very particular bridge, and possibly its adjacent bridge, the Bay Bridge. In fact, the latter’s new eastern span graces the flag and logo of the Golden State Warriors, rendering it in profile, rather than the view from the bridge deck itself. I would consider rendering the GGB if you’re going to feature a bridge.
On that final point, most people – tourists, locals, TV and film camera operators, etc – view and appreciate a bridge from afar. Suspension and cable-stayed bridges are exceptions, but a flat-top bridge is almost entirely unremarkable while traveling over it, but is gorgeous when viewed from another vantage point. The Foresthill Bridge in Gold Country is entirely mundane to drive or ride on, but is breathtaking as the tallest bridge in California, viewed from helicopter above or from the river below.
To be clear, are you suggesting that green should be on left or right, to match nautical/aeronautical practice?
Ships and airplanes display green on the starboard (right) side. Although this would be a neat homage to the practice, I’m not aware if the people of Maine have that strong a connection to shipping or aviation, apart from being a coastal state and at the closest end of the country to flight paths to Europe.
Agreed, the stripes are an unfortunate loss, but I’m pleased they didn’t use the “M shaped” star orientation and instead went for the star pointing north. Neither were from the original submission, but overall, the commission’s work will massively elevate the MN flag. Can’t wait to buy myself a small one for home.
It translates as The Star of The North, or The North Star, in reference to the position of Minnesota as the northern-most contiguous US State, because of the small bit that sticks up higher than the 48th Parallel (aka The Northwest Angle).
From a conceptual perspective, very low quiescent current (aka idle/standby current) when unactivated is entirely achievable. What your design will need to do is assess how much each component will draw at idle, and if it’s too high, then you may need to have gates which turn off those high-draw components when idling.
From a cursory Google Search, the DFPlayer Mini datasheet shows a standby power of 20 mA, which far too high. A forum post shows that if the sleep mode is enabled using the serial interface, current drops to 0.4 uA. This is much better.
For the 555 itself, you mention an astable oscillating configuration, although I’m wondering what your intention for the 555 is. Ostensibly, the DFPlayer either needs a brief pulse to start playing (roughly “edge triggered”) or needs to be kept active for as long as the music should be playing (roughly “level triggered”). In either case, a 555 in a one-shot configuration would make sense, since an astable oscillator would imply the music would restart on its own every so often.
If you’re insisting on the 555, then you may not be able to access the sleep mode in the DFPlayer Mini. So your option might be to gate the DFPlayer so that it only gets Vcc power when the 555 supplies it, probably using a MOSFET. Alternatively, using a cheap microcontroller would let you control the DFPlayer Mini via serial. Your microcontroller could then also receive the signal from the vibration switch and come out of deep sleep to issue commands to the DDPlayer.
The ATTiny uC and MSP430 uC families can draw as low as microamps or even nanoamps in some low-power modes. So that neatly addresses the standby current.
What you’ll also have to assess is the active current, or how much the music player draws when it runs for however long. This should give you an idea of the total lifetime for your application on a single battery charge.
If your coil was oscillating, then perhaps an iron core moving through it would cause perturbations which are detectable. But that would require extra logic to compare the expected oscillation frequency with what the coil is actually oscillating at.
Since you say that tilt switches are not an option – for reasons I’m not entirely sure I understand – another option is to have a linear Hall effect sensor mounted nearby a small magnet. If the magnet moves relative to the sensor, then that is a change which can be acted upon. A linear sensor makes it possible to use a trim pot to tune the sensitivity.
The first link is an SFF-8087 to 4x SFF-8482. While this cable could technically support SAS3 speeds, the SFF-8087 connector was specified for SAS2, not SAS3. As a result, you won’t really find any HBAs that have an SFF-8087 connector and do SAS3 over it. This cable is incompatible with the 9300-8i from your second link. I would choose something more like this: www.amazon.com/dp/B01GPD5KFK . Also be advised that if your SSD isn’t recognized with this cable, the reviews mention that the 3.3v power pin – if you have one at all – might need to be disabled, to avoid PWDIS issues.
For the second link, that Inspur 9300-8i appears identical to the HBA I have, and it’s worked fine for me, although I only have SAS2 drives hooked up to it right now. The nice thing is that the listing advertises “IT mode”, which was important to me, because burning firmware to switch to IT mode is a sad experience.
EDIT: BTW, when you receive this drive, you should probably dump the SMART data to see how much lifetime is left on this SSD. This is an enterprise SSD, so it’s possible that it came from several years of use as a caching drive in a server somewhere. That could do a number to its remaining lifetime, but I would imagine its performance would fit well for your use-case.
I’m afraid I don’t have much experience with benchmarking in Windows. I think I’ve seen CrystalDiskMark mentioned in a few places, and it’s FOSS under MIT License.
BTW OP: when you get this set up, please run some benchmarks and tell this community how it performs. I’ve had a free PM1633A sitting on my desk for 1.5 years, just because I haven’t gotten around to it. I’m keen to know how it behaves.
An aside: one-to-many breakout cables have a forward and backward variety, and care must be taken to avoid buying the wrong one. This link explains the difference, which is still applicable to SAS3: …unraid.net/…/6723-sas-to-sata-cables-forward-or-…
Note that some combinations of backwards breakout cables simply don’t exist, so there might be only one version available for sale. Still, read the product descriptions carefully for which end is meant for the HBA and which end goes to drives or the backplane.
To summarize a few details, the PM1633A is a SAS3 (aka SAS 12 Gbps) SSD drive, which accepts an SFF-8482 plug. This SFF-8482 plug is the one named in the SAS3 standard for use on drives. You mention the LSI 9311 HBA, which does support SAS3 and has a pair of SFF-8643 receptacles, which is specified in the SAS3 standard for use on backplane aggregators. That is to say, when multiple drives are bundled up onto a single cable.
When used for SAS3, SFF-8643 supports up to four drives. And so you will find forward-breakout cables online that go from SFF-8643 to 4x SFF-8482.
The cable you mentioned – an SFF-8643 to SFF-8639 – is meant for U.2 drives. Because of the 4x PCIe lanes used for U.2, a single drive uses all the pins in an SFF-8643 plug, which is why this cable can only attach to a single drive. Because SFF-8639 is backwards compatible with SFF-8482, this could still be used for SAS3 drives, but it would waste the other three “lanes” in the cable.
With all that said, I would not recommend the cable you listed, and instead replace it with the aforementioned forward-breakout to 4x SFF-8482. This way, you can later buy three more SAS3 drives. I presume you’re not planning to ever use U.2 here.
Also, regarding the choice of HBA, was there a reason you chose the 9311? I have both the venerable 9300-8i and a newer 9305-16i. Both work great for me and support SAS3. It’s notable that power and heat is lower on the 9305. The 9300, 9305, and 9311 all have the same pair of SFF-8643 connectors.