Raspberry Pi 2

[Jeff Hutchison]

http://www.mcmelectronics.com/ has free shipping for orders over $199

I would like to order at least one R Pi 2 for myself, and I would also like to get free shipping.  How many people would be interested in a group buy where we would all get free shipping?

Alternatively, does anybody know of a source for the RPi2 at $35 with free s&h?

[Greg Southerland]

You can put me down for one

Sent from my iPhone

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[Frank T.Proulx]

Me as well.

Francois

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Francois Therriault-Proulx, Ph.D.
Postdoctoral fellow
MD Anderson Cancer Center, Houston, TX
Office: 713-792-4626

[Forrest Flanagan]

I'm playing with the odroid c1 instead: http://www.hardkernel.com/main/products/prdt_info.php

[Jeff Hutchison]

Forrest, that looks interesting.. am I correct in thinking that the processor will be 67% faster than the RPi2 and that the Mali GPU will also be faster than the VC IV?  Also, gigabit networking... and RTC.. and IR... sounds like they have the edge on hardware.

BUT... 

http://www.wolfram.com/raspberry-pi/

and...

https://dev.windows.com/en-us/featured/Windows-Developer-Program-for-IoT

[Forrest Flanagan]

Processing power is a complex measure. The ODROID ARM 5 is 1.57 DMIPS/MHz, while the ARM 7 in the RPi2 is 1.9. The frequency difference still gives a definite edge to the ODROID, but there are other advantages. The GPU, for example, is significantly more powerful on the ODROID, and it also supports many more codecs, and the CODEC licenses are included. RPi is unable to include codec licenses. The amount of ram is the same for both boards, but the ODROID has double the clock speed.

I was excited about the wolfram offerings, though I'm primarily a user of wolfram alpha, and I found out their mathematica integration had been pared down to the dwindling features I could already access from the website. Windows 10 is pretty impressive, but RPi has android, which RPi has no interest in at all.

There's a lot of reasons to go either way. For a set top box, or anything primarily for graphics or networking, ODROID is the clear winner. I'll note that I was investigating the chipsets for both boards, and while the ODROID has a dedicated gigabit ethernet Realtek RTL8211F chip, the RPi2 uses a USB to ethernet bridge, which means that the ethernet performance is limited by the USB controller, and the USB bandwidth can suddenly tank on a network. Also, there's no appreciable buffer for the RPi, so if you're sharing USB with something like a webcam, you'll be dealing with periodic TCP drops when your buffer fills up and you can't respond in a timely manner.

There's some minor advantage in using the RPi 2 for things using GPIO, unless you need ADCs and don't want to build a board to hook them up over I2C.

Also, while the ODROID dev community is smaller, it's still there. It is superior hardware all around, and it was out long before the RPi2.

I figured I'd support and educate about the competition, since that leads to better boards and better offerings all around.

[Jeff Hutchison]

Ah... I was under the impression that they had equivalent CPU's just at different clock speeds... the GPU was recognizable as different though!

[Forrest Flanagan]

Oh, and everyone getting an RPi2 should know about the power system bug. Bright lights such as lasers, camera flashes, sunlight at extreme angles, intense nearby light sources, etc, will cause the power supply to either reset or turn off the machine.

The issue is the WL-CSP chip package used in U16 on the board. It's solder balls bonded directly to the bottom of the silicon die, and that leaves a small but significant gap on the underside for photoelectric problems. Consider smearing some paint, sticky tack, or epoxy over this area of the board, but be aware this will create a minor heat issue. spackling it in thermal grease might work, but then it'd be greasy. Ideas anyone?

http://www.raspberrypi.org/xenon-death-flash-a-free-physics-lesson/

[Chris Holloway]

Forrest,

Dave from the EEVblog did a bunch of testing around this and could not get it to reset from lasers, flashlights or anything other that a high frequency xenon flash. 

http://youtu.be/oNlSK4v0kBI

Here's a video of his with a lot of detail around the specific problem chip and why it happens. 

-Chris

[Forrest Flanagan]

I saw the EEV blog stuff and found it to be very cursory and lacking of rigor for the testing outside of camera flashes. Additionally, some of the explanations were misleading, particularly his guesses that infrared spectrum spikes from the camera flash were a likely culprit. The bandgap for the semiconductor is open to interference from a band including UV, the entire visible spectrum, and shorter IR wavelengths. It also appears that the chipscale package does include a blocking layer, so the very low intensity red laser he scanned over the thing may have been mostly reflected, but a blue or green laser, or  a more intense source than an LED from his phone, may have had a more intense effect. 

He did confirm that it takes a massive area of melted blu-tac to block out enough light to solve the problem, that the problem is photoelectric in nature, and that while camera flash EMI can be detected, it is not the cause of any problem.

Also, I don't think the video you linked is the video you thought you linked.