Back from the Dead!


levi

Still fresh, damnit!
Joined
Oct 6, 2008
Messages
15,852
Location
Somewhere off the coast of the EU
One of the rules of taking pictures is: Never ever go over apperature 8. The picture will get blurry due to light bending.
True enough, for 35mm cameras. The aperture is expressed as a fraction in some notations e.g. f/8 - that's because the actual aperture is an eighth of the focal length. Small sensor cameras have shorter focal lengths to achieve the same field of view, so a compact camera will have a correspondingly smaller actual aperture, in millimeters (or whatever units you measured your focal length in), so sooner rather than later diffraction starts to affect your picture.

But given the DoF that ED got, I guess he was using a camera with quite a large sensor, so not going smaller than f/8 is probably a good idea. I forget how to calculate what will be acceptably in focus at what distance and what focal length, but using an old 50mm lens in my camera bag, the scale on it suggests at f/8 and focussing at 1m, you should get a good 40cm in focus.

And as ED explained, since he didn't have the light or a particularly sensitive sensor in his camera, he needed to open up the lens a bit more to let more light in, so took two shots which worked perfectly well to show me what the device looked like.
 

zmatt

Active Member
Joined
Oct 31, 2015
Messages
70
Location
Netherlands
Not everyone is interested in one, I guess, but the SATA-Adaptor has mostly been finished
Wouldn't this design invite putting a lot of strain on the USB3 connector on the pyra due to its leverage? It could be avoided by giving the adapter a female USB3 B socket (normal or micro) and connect it via a cable, though it wouldn't make the overall assembly prettier I guess...

There's no direct JTAG connection on the Pyra PCBs (we didn't have enough space), but the SD-Card slot can be used for it!
All you need to do is boot a special kernel and use this simple SD-to-JTAG-Adaptor.
Dibs on one! :D Soldering the flatcable on will get a bit creative since the signals are not remotely in the right order (the first two signals on the cable are TMS and nTRST...) but it'll probably still be prettier than some of the other jtag cables I've made ;)

The SD card slot is actually even more versatile: Here is an overview I made of which functionality combinations are available (prettified from the TRM). Columns show modes of operation, rows are pins, and you can ignore the low-level info on the left.
 

rv6502-2

Still Fresh
Joined
Jan 17, 2016
Messages
28
Location
Volcano Base
Website
rv6502.com
Wouldn't this design invite putting a lot of strain on the USB3 connector on the pyra due to its leverage? It could be avoided by giving the adapter a female USB3 B socket (normal or micro) and connect it via a cable, though it wouldn't make the overall assembly prettier I guess...

If I was going to use a SATA drive I'd either:
  • Use a short USB3 extension cable with the adapter.
  • 3D print a dock, remove the USB2 socket from the adapter and hard-wire a USB2 hub to the adapter inside the dock.
  • On the go: get a cheap 5V external USB-SATA case, gut the electronics, get a very flexible USB3 cable and wire the 5V + SATA signals directly into the gutted USB HDD case.

But in my use case I don't think I'll need more than what (2 SD + 1 microSD) cards and the 32GB internal storage can give me.
In regards to the speed the Linux kernel caches everything it can into whatever amount of RAM is currently free.
Even on the GPD Win with 4 cores at 2.5Ghz (eventually overheating) I can't saturate the internal eMMC while doing builds, the Linux kernel caches and buffers everything in RAM. I can't find a likely use case with the Pyra that would really benefit from the SATA port compared to USB3.

For data recovery USB3 docks have plenty of bandwidth and I'd rather not plug a defective HDD directly to the expensive Pyra anyway. Leave a USB Hub and HDD Dock(s) between them to shield the Pyra.

For doing a native build server I think a Raspberry Pi 3 with a Pyra OS chroot would likely be faster and leave the more expensive Pyra free to do the portable things it is best at.
(1.2 GHz x4 Pi3 vs 1.5Ghz? x2 Pyra)
 

hns

Well-Known Member
Joined
Dec 4, 2011
Messages
637
Location
Oberhaching
Yes, but there is no way to directly power it from the pyra. There were some housings with eSATA + external PSU, no idea if they still exist.
This is what I have used to test the Pyra SATA adapter:

a) Logilink qp0011 external USB/SATA docking station with separate power supply (https://www.heise.de/preisvergleich/logilink-quickport-weiss-qp0011-a728827.html)
b) 1m SATA III to eSATA cable (the Logilink has an eSATA socket)
c) some spare 1TB WD10EZEX desktop hard drive (btw: it is specified to need 0.68A@5V and 0.55A@12V so this would translate to ca. 2A@5V when using a 5V -> 12V DC/DC)

Boot and we get a /dev/sda (plus partitions).
 

Black Sliver

Member
Joined
Apr 5, 2016
Messages
53
(btw: it is specified to need 0.68A@5V and 0.55A@12V so this would translate to ca. 2A@5V when using a 5V -> 12V DC/DC)
For typical boost designs, the peak efficiency is between 80% and 90% -> 2.3A.

What's the max. output current of the USB connector/battery/charger?

WD Red, which I'd prefer and recommend, need 0A@5V + 0.28..0.53A@12V (depending on size) during write. The peak current of 1.2-1.8A might be a problem; if it has UVLO or soft-start, it might be possible to run it from 5VDC@1..2A with a huge cap.
 

Lightkey

Member
Joined
Jan 26, 2014
Messages
60
zmatt: I would not worry about the design, I'm guessing at least 90 % would be stationary use.

rv6502-2: I don't see the use for the first two options but the third would be rad!
Of course copying to or from SD or eMMC will not be better than the USB 3 port but what if in my case I often copy from one HDD to another or to a USB stick? Also, I can still make full use of my external eSATA drive that way, which otherwise only has Firewire or USB 2 available. Not really hard to understand the advantage this gives.
The SoC of the Raspberry Pi 3 does not have the same cores as the Pyra. Benchmarks suggest they are about even in multi-threading.

hns: Coincidentally, mine is also a WD 1 TB drive but with external housing. ;-)
 
Top