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Comment by awjr | Hacker News Reader

I have to say, the Pi 2 comes across less as a bit of fun and more as something you can really start doing interesting things with.

Currently investigating image processing and ANPR using OpenCV.

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Say no to OpenCV, unless it got mayor redesign. Its great for experimenting and prototyping, just like GNU Radio Companion, but its nickname is 'lets copy that buffer one more time'. First thing you do when serious about image processing is you DO NOT deploy OpenCV on the end product. You settle on algorithm that works for you, and reimplement it in C (or verilog) as close to metal as you can get.

Definitely agree with this. I got Face Detection using OpenCV on a 320x300 video stream to work at about 2fps (e.g. two detection cycles per second) on the B+ over-clocked to 1Ghz so hopefully the Rpi2 will be a substantial improvement on this.

I was using it the context of controlling the "eye" of a wheeled robot so both the eye and the robot could follow faces. 2FPS was workable on this but 320x300 didn't give it much of a field of view.

Are you aware that there are already more powerful tiny ARM single-board computers on the market that fit in the same size, power and price envelope? Like ODROID: http://www.hardkernel.com/main/products/

From $35 4x1.5Ghz Cortex-A5 ODROID-C1 to $99 octa-core Exynos5422 ODROID-XU3 Lite (4x1.8Ghz Cortex-A15, 4x1.3GHz Coretex-A7, plus OpenCL 1.1)

They have their own ecosystem and monthly magazine (sic!). Raspberry Pi is one of the first and most popular; it's great for beginners, but if you really need to push the envelope there is always competition that tries to undercut them in price, performance and/or features. Now again, RPi 2 has set a new bar, but it is not that high.

> Raspberry Pi is the first and most popular

While certainly most popular, I'd dispute the claim of being first. For example BeagleBoard was initially released in 2008.

Oh, you're right.

Yep absolutely, have been wondering about the C1, my only concern is that getting OpenCV and some of the supporting libraries to build on the Pi was a big challenge but doable because there's such a large community to help out. The same was true with WiFi and Camera drivers.

So the C1 and related boards look great but I'm cautious of building around something with a smaller community just because of the potential for it taking far longer to troubleshoot the underlying stuff I need setup to work on the actual project. That said I'm pretty sure I'll succumb to a c1 in the next couple of months!

Given that the only thing that has changed is the more powerful CPU, I'd say same fun and more interesting things! ;)

RAM also doubled to 1GB.

First generation B model was 256MB, later it was doubled to 512MB.

And ARMv7 is a big deal, as the article points out..

Yeah but I don't think its niche will change as much. It fell slightly short in terms of processing power at not so many things. Obviously the faster the better though.

Actually one of the biggest failings of the original Pi was that you couldn't do timing-sensitive I/O operations on the GPIO pins reliably. If you can dedicate one of the 4 cores for GPIO processing (we're not talking a lot of data throughput here), that problem goes away. My biggest beef with the Arduino platform is that the CPU/RAM is just too small to really do much with other than act as a pure sensor<->serial bridge -- and functional GPIO means the new Pi is essentially a half-price replacement for an Arduino Yun.

You'd probably need to write the code in C/C++ (rather than Python or some other interpreted language) to get deterministic execution, but that's an acceptable limitation in my mind.

Is there an implementation of RTLinux on ARM? If so, is it (mostly) compatible with the RPi2?

Black Swift [1] guys are telling us: [2] "Want realtime I/O? Add yourself an ATtiny MCU [3] for under $1."

Black Swift is a newer, tinier single-board computer - for 'a bit more embedded' computing than the Raspberry Pi. No audio/video, but a built-in Wi-Fi. Actually, its central SoC in itself is a recent Atheros Wi-Fi chip that happens to have a 400 MHz MIPS 24k CPU embedded. Here's where Black Swift founders see themselves in comparison to the competition: http://www.black-swift.com/images/wiki/BlackSwift-competitio...

[1] Black Swift — tiny wireless computer https://www.kickstarter.com/projects/1133560316/black-swift-...

[2] Using AVR as peripheral controller https://www.kickstarter.com/projects/1133560316/black-swift-...

[3] ATtiny24A http://www.atmel.com/devices/ATTINY24A.aspx @Octopart https://octopart.com/search?q=ATTINY24A&filter%5Bfields%5D%5...

Some timing sensitive operations like PWM are possible on the old Pi by making the DMA controller directly transfer data from hardware PWM to GPIO without using any CPU cycles.

Frameworks like pigpio and servoblaster use that trick, but the standard gpio python module which doesn't use DMA has more mindshare, probably due to its simplicity.

There is an implementation of RTlinux for the RPi from the Navio guys [1], but I'm not sure if it's compatible with RPi2.

[1]: http://www.emlid.com/new-raspbian-with-real-time-kernel-jan-...

I doubt that you could easily dedicate one core for RT GPIO while running regular Linux on the rest. That would require quite significant engineering both from the kernel and HW. Probably a better architecture would be something like the PRUs in OMAP SoCs used in BBB, i.e. semi-independent RT co-processors.

Besides there is lots of devices in the market positioned between Arduino and RPi. STM32 F4 Discovery board is a good example; an order of magnitude more processing power than an Arduino Uno but still a MCU designed for bare-metal (real-time) operation.

It's why I'm using Beaglebone Black for a project involving many RGB LEDs that have a timing-sensitive protocol - it has two "programmable realtime units" on-die with the CPU. It's a pair of separate cores (200mhz, IIRC) that can handle in hardware the kind of software bit-banging that needs to be done on RPi, and it shares some memory with the CPU. It's able to process or raise interrupts, too. It can handle ADC, PWM, and probably a few other TLAs that I'm missing.

Could you elaborate on this point? I'm curious as what the new architecture will help with, other than the porting issues mentioned in the article.

Math, lots and lots of math. The new chip has an actual floating point unit instead of it being emulated, support for the NEON SIMD extensions, both of which will definitely help in speed in dealing with any amount of number crunching. It's also got virtualization extensions, so you should be able to run Xen on it and do some level of OS development if you wanna get one for that. Really, it boils down to a lot of little differences that will line up together to make a lot of tasks on the Pi a lot easier to handle.

The previous RPi did actually have hardware FP, see http://raspberrypi.stackexchange.com/questions/545/does-the-.... I think the arch support is probably the big issue - any standard Linux distro with an armhf port will work on the new RPi. Probably gets you access to a lot more interesting Debian packages than you did with Raspbian.

Thanks for the correction. I recalled the original release of debian for the Pi didn't have floating point support, but did not recall that that was because Debian was building towards the least common denominator. I don't think you'd get that many more interesting packages with the new arch, but you probably will get a lot more usability out of the packages

Hm, I've plenty of fun and more interesting projects than I can count with the prior model too.

I like the fact that processing speed has been boosted but that's all there is to it.

Any chance of a link to some of these. I have started volunteering at a coderdojo and we have plenty of RPi's I just need some inspiration for projects, or more accurately I want to inspire the kids and would like some examples we could work on while they think of their own.

Have you looked at Minecraft for Raspberry Pi ( http://pi.minecraft.net/ ) ? It can be scripted using Python. Great way to get kids hooked.

Yeah, I poked at that one just a little bit, but found it pretty limited and kinda buggy. Felt like it was fired off and forgotten. But, hey, maybe with Microsoft buying Minecraft and doing Win10 for the Pi, it will get a second look. (maybe. ha.)

Here are a few ideas:

* http://www.hackster.io/raspberry-pi

* http://hackaday.io/projects/tag/raspberry%20pi

* http://raspberry.io/projects/

One of my projects: https://unop.uk/dev/raspberry-pi-electricity-monitor/

http://www.dexterindustries.com/GoPiGo/

I'm really happy about the 4 USB ports too. It was a pain having to use a USB hub on my Model B to get keyboard+mouse+WiFi.

I run headless so don't run into that problem... it would be nice to get some more power so I could plug in a hard drive without having to use a USB hub, though. Tried it a few times without a hub and the drive keeps clicking - spinning down may be the right term? So I've held off on using it as a media center which is what I really want to do.

The power circuits were revised quite a bit in the B+ (and 2), and also between early spins of the Pi and later ones. You may have better luck with a later board revision - I have a Pi B from the very first batch and it can barely keep a backlit keyboard going, but never bothered returning it because I don't use its USB anyway. There's also a lot of flaky USB power supplies out there - make sure yours is solid.

The previous model already had 4 USB ports.

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