A probably not so small rant about the Raspberry Pi - Page 1
Forum section: electronics / general

author: MrSlack
author_rank: Frequent Contributor
timestamp: March 01, 2016, 10:18:49 am
content: I've just had the inevitable email conversation about the new Raspberry Pi 3 at work. To dispel a few myths I dumped this out to the team. I've had every Raspberry Pi device that has come out and they are disappointing to say the least. It also seems to be shrouded in a mire of politics and media frenzy strung with reality distortions and carefully controlled perception and that's enough to make me look elsewhere....from the email...But it's so small- It's really not. It's quite big actually. The Pi zero was quite small, until you add all the peripherals required to do anything. Even the smallest USB connectors turn it into a minimum 4" square device. The board is small, the solution is not.It's great for teaching- I hear this a lot. Frequently promoted as "teachers can just wheel out 20/30 of these to a class and teach everyone to code!". It's really not like that. I was talking to the mathematics/IT teachers at my daughter's school and they have have a lot of them. They live in a cupboard, either broken or unused. They aren't mechanically or electrically robust enough for an educational environment. You have to throw them away once every three months at the very best. On top of that, the software environment and storage model is so bad they spent half a lesson fixing and reimaging the things with NOOBs. When they break, it takes two weeks to get a PO raised and through the system and then there are usually stock level problems so they are down for 1-2 months at a time. So they installed python on the normal desktop PCs and just use them.I can stick it in a rocket/drone- they weigh way too much for that. Add the quite extensive power requirements and the ancillary peripherals and there are better choices out there. If it was good for the job, there wouldn't be so many better alternatives.The community is great- it's really not. When the original Pi came out I tried to get it working with composite video. I carefully and politely documented every roadblock I encountered and posted this on the forum and asked for them to look at this in context to the Raspberry Pi 2. What engineer doesn't want to hear bug reports and improve their product? Well clearly Mr Upton and the crew because the post was deleted instantly.I can use it as a smart mirror in my bathroom- you probably can't, legally at least here in the UK. The one use I've seen of this violated electrical safety regulations and was scary to say the least. IP rating? Nope, just a switch mode on the end of an extension lead hanging inside a condensation collector. I think people need to be way more critical of designs like this but that's an IMHO.It's better than a second hand desktop PC- it's probably not. They come with decent disk controllers, decent memory, are far more extensible, robust and more reliable. Plus you can get a ton of them from ebay for less than the price of an entire Pi setup. If you really want to push it, a £100 laptop is a better proposition and takes less power when you consider the additional energy cost of the screen and all external peripherals.It's open source!- It's not. The SoC is still mostly closed or has restrictive licenses. There's a layer over the top from the kernel and above that isn't. I occasionally hear in defence that the PC BIOS is closed source. Yes it mostly is but it gets out of the way when it's done andIt's the best selling computer ever- There are at least three orders of magnitude more PC clones in landfills than any Pi that have ever been sold.It's so cheap- it's really not. There are cheaper, better alternatives. If we consider value, it's pretty low on the rankings.Last random comment: as someone else pointed out here, you have to buy a new case each time. There is zero standardisation and this turns into a large market for accessories and specialist peripherals which large premiums are charged for.Rant over. Sorry.

author: jeremy
author_rank: Super Contributor
timestamp: March 01, 2016, 10:40:00 am
content: Allow me to add:The USB cable doesn't actually do anything USBThey now draw so much power that you can't power them off a USB port anywayYou have to buy an SD cardMost USB peripherals that aren't mice or keyboard (but sometimes even those!) need a powered hubI've seen tertiary students destroy arduinos with a rate of 25-50% per student; how anyone expects a more complicated device such as the rpi to be better is beyond me.I've recently been wowed by the NTC CHIP; it is $9 (yes, they sell it at the price they claim!), and has 4GB of onboard flash. Oh, and you can actually access a serial console over the USB power cable, and it can run off a laptop USB port. Quite a fantastic little thing.

author: MrSlack
author_rank: Frequent Contributor
timestamp: March 01, 2016, 11:24:41 am
content: It's about the whole line of devices. All the criticisms are empirical and therefore valid.

author: tom66
author_rank: Super Contributor
timestamp: March 01, 2016, 11:39:13 am
content: So, I use a Raspberry Pi 2 behind each of my TVs in the house. One in the living room, one in the bedroom. I think it's a great device.Each Pi drives the TV only and connects over ethernet to a central media NAS drive. They are capable of playing 40Mbit h264 Blu-Ray images of Avatar @ 24Hz and 60Hz 1080p at up to 30Mbits. These things use so little power I leave them on all the time. They draw 250mA @ 5V, or less than 1.5W. They use CEC to interface with the TV remote (the TV remote is the interface for the Pi via Panasonic Viera Link.) They run off the TV's own USB port and are stable as a rock, one of mine has an uptime of 2 months now.Before the Pi came out there were very few low-power devices on the market capable of playing full HD video that also ran open source software. I can't think of any sub £150. The BeagleBoard & BeagleBone didn't have video decode hardware, so wouldn't do anything more than 480p. Of course I could use a desktop PC, but that needs fan cooling (noise!), and draws 50W minimum. An Atom board might do fine with just a passive heatsink, but it will still draw a lot of idle power and costs a lot more than a Pi.We are using a Pi 2 in our university group project. The high speed control logic is operated off a dedicated MCU, but the heavy duty, OK for latency stuff is run off a Pi. It is running multiprocess Python, OpenCV, capturing *and* encoding 1080p@30fps video and driving a HDMI monitor 1080p@30fps ... and the board costs £30. It's hard to beat that.Now the Pi Zero is out and I do not yet have one because it is so popular they cannot keep it in stock. I wish the Pi Zero came with onboard wi-fi, and apparently there are no plans to support it. But still, on its own it's a ludicrously powerful 1GHz ARMv7 processor with HDMI video and it runs Linux. For £10 or so it's really hard to go wrong.

author: MrSlack
author_rank: Frequent Contributor
timestamp: March 01, 2016, 11:46:35 am
content: My TVs (Bravia EX) do DLNA and have ethernet and the NAS (Synology DS4) has a DLNA server so I don't have any kit for streaming. This was a careful design choice.I used a Pi Zero myself for a few weeks. It hung behind my living room television for a bit as a script server running a few python scripts I have. The problem I had was that it was so incredibly slow. I moved the scripts to digitalocean and instead of a 3 minute script run every 5 minutes it was a 12 second script run every 2 minutes. In situ, powered off the xbox, with a USB ethernet wart and associated adapter to show how damn inconvenient it is...

author: AlxDroidDev
author_rank: Frequent Contributor
timestamp: March 01, 2016, 12:30:13 pm
content: Quote from: MrSlack on March 01, 2016, 10:18:49 amThat's marketing. Give out samples to bloggers (or online magazine writers) with little or no technical background and they'll write wonders about whatever device they're given. Sometimes even a press release is enough to create such hype around a product.The same thing is happening to Batterizer: look at how many positive articles have been written about it, prasing it as the second best thing after air-conditioning. Yet, for all we know, the product doesn't even exist and, even if it did, it is a total scam. Neverthless, there are reputable sources writing good things about it.I liked your post and agree with most of it, specially the part about it being unusable on an academic environment. It is just too fragile for that. Schools need something more robust. Even one of those cheap OLPC notebooks are better able to withstand the abuse of a classroom.

author: Mechanical Menace
author_rank: Super Contributor
timestamp: March 01, 2016, 12:43:38 pm
content: If you want robust and little kiddy classroom friendly get one of these:

author: MrSlack
author_rank: Frequent Contributor
timestamp: March 01, 2016, 01:02:58 pm
content: That was what I started on. Definitely. Although I did get though a couple of 6522's

author: Artlav
author_rank: Frequent Contributor
timestamp: March 01, 2016, 01:13:42 pm
content: Quote from: jeremy on March 01, 2016, 10:40:00 amWhy is that a bad thing?

author: Wilksey
author_rank: Super Contributor
timestamp: March 01, 2016, 01:26:19 pm
content: Is the RPi (or derivatives) designed to replace the desktop PC? no!Are you able to make one yourself at home? Not unless you work for Broadcom or want to buy 100 million of the SoC's, no!Does anyone really care? Not really...What you use it for is entirely up to you, it's an embedded Linux based SBC, it has a decent spec, i've used it for all sorts of things from a media device for the TV, small web server, through to something simple like a sensor data gateway.As long as you know it's limitations you can work with it, I can't really see anything wrong with it.

author: jeremy
author_rank: Super Contributor
timestamp: March 01, 2016, 01:41:45 pm
content: Quote from: Artlav on March 01, 2016, 01:13:42 pmBecause it is no longer a "$35 computer" in any realistic sense, it just becomes a disappointing marketing slogan. While one could argue forever about the relative merits of on-board vs removable storage, the truth is that if you wanted to fill a classroom with them (which I thought was the original goal of the device), it's still 20-50% extra.Keep in mind, I say this as someone who has 5x raspberry Pi 2s on my desk. I guess the thing I personally find a bit silly is that everyone still seems to be claiming "it's for education!". Truly, the only people I know who actually have raspberry Pis of their own volition are young adult and middle aged men, and it's use is always related to playing hd video. I am perhaps the only exception to my own experience; I use them to experiment with networking.

author: jeremy
author_rank: Super Contributor
timestamp: March 01, 2016, 01:51:58 pm
content: Quote from: Wilksey on March 01, 2016, 01:26:19 pmI think perhaps the problem is that they have been marketed this way. Of course, to someone who seeks out a forum like this, the technical distinctions are quite clear. But to those with less of a grasp on these topics, desktop == PC == computer, so when the tagline is "$35 computer" hopefully you can appreciate that some find this misleading. I have seen this first hand when trying to explain exactly what a raspberry Pi is to people without much technical background. I usually just settle for "its like a computer, but not", so perhaps I am part of the problem

author: Mechanical Menace
author_rank: Super Contributor
timestamp: March 01, 2016, 02:11:32 pm
content: Quote from: MrSlack on March 01, 2016, 01:02:58 pmI'm only a couple of years older than my B+. It survived my father, was mine (and in my room) 3 years later when I turned 5*, 10 years later my little sister learned BASIC on it, and 12 years after that so did my little brother. It's still in 100% working condition and the only cosmetic issues is the yellowing. Well more browning tbh.I don't quite agree with all your criticisms of the Pi, but I do think it's too complex and fiddly as a first introduction to computing beyond browsing the web or using a word processor. These older, much slower machines are brilliant for that. Start them on a BBC or MS BASIC machine (say a C64) and they have a great start on understanding how computers actually work before they move on to a Pi and Python or C/C++. They are also brilliant to go back to if someone wants to get a hang of assembly. Yeah, BASIC has it's problems that I'm not going to disagree with when it comes to "real" coding, but it's a great teaching tool.*And still got used when I upgraded to STs and Amigas.

author: tom66
author_rank: Super Contributor
timestamp: March 01, 2016, 02:21:53 pm
content: Quote from: Artlav on March 01, 2016, 01:13:42 pmThis won't be true for much longer. The RPi3 is stated to support USB or PXE network boot, and there's talk of backporting this across all devices including the original RPi and Pi Zero, dependent on hardware and software resources.Besides it can run off anything - the SD card is currently only needed for the boot image. You could use a 256MB microSD and then run it off a pendrive or over the network. This new configuration ought to eliminate the need for the SD card as well.

author: Artlav
author_rank: Frequent Contributor
timestamp: March 01, 2016, 03:18:37 pm
content: Quote from: jeremy on March 01, 2016, 01:41:45 pmHm, aren't SD cards $1-$2 apiece in the 2-4Gb range, especially in 10+ quantities?In the teaching environment that would also speed things up, no?Just swap a card when someone trashes the system, instead of spending time reflashing the onboard storage.Quote from: jeremy on March 01, 2016, 01:41:45 pmHeh.Not the only - i got a bunch of them tied into a miniature "cluster".However, after initial tests and runs, i still haven't figured out what to USE it for...So it just sits there helping keep the temperature warm in the winter...

author: Kilrah
author_rank: Unknown
timestamp: March 01, 2016, 03:30:14 pm
content: Quote from: Artlav on March 01, 2016, 03:18:37 pmCrappy slow ones you'd need to buy in bulk from sellers a school probably couldn't order from, yeah...

author: karoru
author_rank: Regular Contributor
timestamp: March 01, 2016, 03:42:32 pm
content: Quote from: MrSlack on March 01, 2016, 10:18:49 amThat's what also makes me scratch my head every time. Students have these things called personal computers (mainly laptops), nobody writes lab reports on a typewriter/by hand nowadays, so they kind of have the possibility of installing Python? It takes 3 minutes to install Python on Windows (click "Next" few times and done), and virtually every Linux/OS X nowadays have some version installed by default. And in classroom you have to connect keyboard, mouse & some display to Pi anyway, so what's the difference between it and using old desktop PC lying around in storage closet?

author: Philfreeze
author_rank: Regular Contributor
timestamp: March 01, 2016, 03:50:44 pm
content: The Raspberry Pis are pretty good for software guys to learn some hardware stuff (easy access from within Linux to the IOs), my father uses it for that.The other application for it is as a mediacenter behind your TV (which we have) but that is about it.Most of your points are valid and there is a lot of marketing behind it.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: March 01, 2016, 04:06:06 pm
content: I tend to agree with the original poster. But I do have a couple myself, one used to run a GPS derived NTP server (until I realised I didn't need a NTP server) and another runs a base station to talk to RFM69W based things distributed around the house (the things are not Pi; due to power constraints).I think they are fun but I bet if you analysed the usage compared to sales you would find the vast majority of them are currently gathering dust somewhere in the back of a drawer.

author: dan.soethe
author_rank: Contributor
timestamp: March 02, 2016, 11:29:27 pm
content: The raspberry pi is supposed to be the hackable equivalent of the early 6802, z80, and 8080 computers that alot of us grew up with.. and they're trying to encourage the next generation of computer system engineers to emerge.Most kids I know today are totally oblivious to what goes on behind their phone's screen.With a raspberry pi, we now have a way for them to discover the inner workings of that phone. And what else you can do with that device...Sent from my SM-G900P using Tapatalk

author: Muxr
author_rank: Super Contributor
timestamp: March 02, 2016, 11:43:43 pm
content: I don't get much of the criticism. I do agree that it's overrated in some aspects. But it is a cheap affordable single board computer with plenty of support. Certainly more support than CHIP you mentioned.I use an rPi A as a 3D octoprint server and it works amazingly well. It's been running for 2 years now. Can't think of a better cheaper or smaller solution I could have used instead. I have a friend who uses a solar powered Pi for a wireless camera gate system, and it works great. I can't think of a competing product that could have done it easier than Pi.It is not ideal for electronics. It can sort of do it, but that's not what its real primary focus is. You have a slew of microcontroller dev boards for that stuff like Arduino, Teensy or any other eval boards from big MCU companies. Also if you decide to produce the solution you can actually buy those chips, which is the biggest problem I have with Pi (you can't buy Broadcom chips).Pi Zero is awesome. $5 single board computer that runs a full Linux stack? Are you kidding me. That stuff is amazing. You're not meant to use it as a computer. You're not meant to have a keyboard and mouse connected to it permanently. It is supposed to be used as a module in a design.And ultimately Pi as its name implies is meant to provide a single board computer with some GPIO you can program in Python. That's its primary purpose. And nothing on the market does it better.It obviously isn't going to be well suited for embedded applications like a flight controller on a drone. It's supposed to bridge the gap between real time applications where RTOS and embedded code thrive and a traditional POSIX OS with support for full featured frameworks and scripting languages, traditionally run on much bigger wintel machines.

author: c4757p
author_rank: Super Contributor
timestamp: March 02, 2016, 11:48:32 pm
content: Quote from: dan.soethe on March 02, 2016, 11:29:27 pmI think I kinda like the Pi... but I don't understand the "inner workings" argument. What "inner workings" does the Pi expose you to that dicking around on a computer or something does not?

author: station240
author_rank: Unknown
timestamp: March 03, 2016, 12:03:41 am
content: Quote from: MrSlack on March 01, 2016, 01:02:58 pmYeah the 6522 has another advantage over the Raspbery Pi, the outputs for one port are simply 8 bits. Where as on the pi, to get an 8 bit output, you have to deal with the random numbering of available bits over the entire 32bit bus. Trying to connect say a parallel printer to a Pi requires bitbanging every single byte you send.Whoever decided which GPIO ports to use for internal hardware on the PI really needs their head examined.

author: jeremy
author_rank: Super Contributor
timestamp: March 03, 2016, 12:05:54 am
content: Quote from: c4757p on March 02, 2016, 11:48:32 pmVideoCore IV blobs and undocumented supervisory processors

author: Muxr
author_rank: Super Contributor
timestamp: March 03, 2016, 12:06:13 am
content: Quote from: station240 on March 03, 2016, 12:03:41 amOr you could just use a $0.30 shift register with SPI.

author: dan.soethe
author_rank: Contributor
timestamp: March 03, 2016, 12:13:42 am
content: Well, back with 8-bit micros. We got familiar with registers and interrupts a clock cycles.If you wanted something to show up on the screen You had to poke it or print it or use assembly language.Now it all automatic, unless one learns more about the device...But kids nowadays are more interested in social media than how they could write there own.Sent from my SM-G900P using Tapatalk

author: eugenenine
author_rank: Frequent Contributor
timestamp: March 03, 2016, 12:14:47 am
content: Quote from: jeremy on March 01, 2016, 01:41:45 pmI paid $29.99 and used the 16G MicroSD that was in my phone when I replaced it with a 32G MicroSD. I used the old phone charger from the phone my son lost so Mine cost $29.99 total.

author: jeremy
author_rank: Super Contributor
timestamp: March 03, 2016, 12:16:17 am
content: Quote from: Muxr on March 02, 2016, 11:43:43 pmHave you actually used the CHIP in order to draw these conclusions? I only got one less than a month ago, and I was one of the first backers. Literally everything worked straight away, connecting to a WPA2 network was a single command, and didn't involve kernel panics (which is definitely not the experience I had with the raspberry pi, even years after it was released).You can program the GPIO in python too if that really is a big deal... it just uses the kernel gpio interface like every other SoC running linux.But really, I've got nothing invested in CHIP, whether they succeed or fail is no big deal to me.

author: jeremy
author_rank: Super Contributor
timestamp: March 03, 2016, 12:20:50 am
content: Quote from: eugenenine on March 03, 2016, 12:14:47 amPlease, don't be like that. The full paragraph is: "Because it is no longer a "$35 computer" in any realistic sense, it just becomes a disappointing marketing slogan.While one could argue forever about the relative merits of on-board vs removable storage, the truth is that if you wanted to fill a classroom with them (which I thought was the original goal of the device), it's still 20-50% extra."

author: Muxr
author_rank: Super Contributor
timestamp: March 03, 2016, 12:23:32 am
content: Has CHIP even shipped to all its backers? I don't understand how support and ecosystem is even debatable.

author: jeremy
author_rank: Super Contributor
timestamp: March 03, 2016, 12:25:15 am
content: Quote from: dan.soethe on March 03, 2016, 12:13:42 amI am not sure if you are aware, but there are still many undocumented features like the CSI and DSI interfaces. And the raspberry pi folks have openly stated that they are not planning to document them or provide details on their workings.

author: jeremy
author_rank: Super Contributor
timestamp: March 03, 2016, 12:29:39 am
content: Quote from: Muxr on March 03, 2016, 12:23:32 amI guess my statement is more like "Even when the raspberry pi was much more mature than the CHIP, I was still having issues with the raspberry pi that I have not had with the CHIP". If by "support" you mean stuff works and there are people to help you, then I really don't see too much of a difference between early rpi and CHIP.OT: CHIP is a terrible name

author: dan.soethe
author_rank: Contributor
timestamp: March 03, 2016, 02:07:50 am
content: Quote from: jeremy on March 03, 2016, 12:25:15 amYes, I know about that, but it's broadcom that is the stickler.But some smart person is bound to reverse engineer it then wiki-pedia will disclose it to the world...Sent from my SM-G900P using Tapatalk