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Unpopular Opinion: Don’t Use a Raspberry Pi for That

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Re: Unpopular Opinion: Don’t Use a Raspberry Pi for That

#201

Post by outworlder »

retrocryptid wrote: post #4

I know that you didn't ask, but my $0.02 is that yes, RasPi's are unreliable. If you use one for as an unattended remote server, it will do you well to include a hardware watchdog that power cycles the device after it hangs. But modern NUCs seem to take MINUTES to boot the BIOS. I had been using various BeagleBones and found them more reliable than RasPi's and faster to boot than the NUCs in the office. But depending…

> I know that you didn't ask, but my $0.02 is that yes, RasPi's are unreliable. If you use one for as an unattended remote server, it will do you well to include a hardware watchdog that power cycles the device after it hangs.

Maybe you got a bad batch. My Pis never had any problems whatsoever.

Please check logs to see if they are experiencing brownouts. Not all power supplies work, specially with a Pi4.

The thing that likes to fail a lot is SD cards. My homeassistant Pi uses a SSD(harvested from an old Chromebook) because of that.

TinyMiniMicros seem to be a better option than NUCs these days. Boot faster too.

Re: Unpopular Opinion: Don’t Use a Raspberry Pi for That

#202

Post by xp84 »

SkyPuncher wrote: post #186
some_random wrote: post #27

I typically see two kinds of raspi hate, and only one of them is reasonable imo. The first is stuff like this article, where you can probably get something better than a raspi these days for about the same price (especially when you consider scalper pricing) or just run a docker image in a server you can make with an old computer. This is very good advice, especially now that getting a raspi at MSRP is borderline imp…

I've done embedded programming, but I just don't enjoy it. It's far too in the weeds for the type of simple tasks I want to do around my house. Every time I start with Arduino, I realize that I'm simply not having fun. Raspberry pie lets me work at a higher level that I actually find enjoyable.

Totally respect this. Especially for "household" things.

There's an alternate timeline where CPUs are really hard to make, so every SOC 'wasted' on a curtain-opener or a glorified doorbell deprives someone who badly needs a general-purpose computer and can't afford one. But in our timeline, every day probably a million perfectly good "computers" (cell phones, desktops, smart speakers, etc) get tossed in e-waste anyway, so it's not a sin to use an overkill computer for a task. (Ironically of course the Pi itself is in a shortage but... :shrug:)

Re: Unpopular Opinion: Don’t Use a Raspberry Pi for That

#203

Post by outworlder »

retrocryptid wrote: post #103
magicalhippo wrote: post #41

Earlier quoted context omitted.

> I know that you didn't ask, but my $0.02 is that yes, RasPi's are unreliable. I've been using RPis and "clones" for internal services for years, and there's hardly any fuzz with them at all. At most a power cycle once a year. They've endured house losing power multiple times, I've yet to swap SD-card on any of them, they just keep chugging. But sure, I wouldn't trust my life to one. I just find it odd that people s…

Happy that yours works well. Many problems don't show up until you hit larger numbers. We deployed over 1k RasPi's for a particular customer. We averaged about five reboots per day. On top of that I had to deal with the RasPi Organization's insistence that they were not an ODM. Though these were the RasPi B's and RasPi2 B+'s. I'm sure the reliability has gotten better over the years. I'm not a big TI fan, but everyth…

... what were they doing with 1k Pi's

Please tell me they were using the GPIO pins for something.

Re: Unpopular Opinion: Don’t Use a Raspberry Pi for That

#204

Post by rleigh »

lll-o-lll wrote: post #122
dale_glass wrote: post #75

Earlier quoted context omitted.

There are different kinds of timing issues. There's knowing the time, which you can do with something like NTP. That the RPI can manage just fine. And there's acting with precise timing, eg, if you need to control a mechanism and reliably react on a deadline of a few ms. A RPI doesn't perform well there, which is why 3D printers use microcontrollers instead.

Bare metal C++ for PI. https://github.com/rsta2/circle Access to most of the hardware and real-time deterministic behavior. It’s a really great project and lets you twiddle those gpio pins at ridiculous speeds with perfect timing (less than a millisecond). A PI comes with a whole bunch of great hardware baked in, so if you have one laying around, and want to do some microcontroller stuff, I think it’s a great choice.

It's still an A-profile MPU and not an R- or M-profile MCU, and while it will be fast it will have less deterministic behaviour than we might like. If you disable the caches and MMU you'll get better consistency. But wouldn't we expect ~microsecond accuracy from a properly-configured MCU?; ~millisecond accuracy is not a particularly high bar.

Re: Unpopular Opinion: Don’t Use a Raspberry Pi for That

#205

Post by outworlder »

mnw21cam wrote: post #137
causi wrote: post #93

RPi prices are so inflated they barely make sense at all, let alone for all these little "give my plants half a cup of water every day" projects.

The power available in a RasPi is way overkill for "give my plants half a cup of water every day" projects too. I don't need four cores and dual HDMI outputs to tell a motor to spin for half a minute once a day. I'm just building a outside watering system. I was going to use a RasPi, simply so that it can log the things like temperature, light levels, rainfall, and water butt levels that it uses to work out how much…

> I'm just building a outside watering system. I was going to use a RasPi,

You could also use a $1 ESP8266 or a slightly more expensive ESP32.

Re: Unpopular Opinion: Don’t Use a Raspberry Pi for That

#206

Post by outworlder »

geocrasher wrote: post #11

If you don't need GPIO, then you don't need a RPi. They are useful, but an old laptop can do most things a Pi can do, and putting them to use keeps them out of the landfill longer.

> If you don't need GPIO, then you don't need a RPi.

You might not need a Pi. You can by a hundred ESP8266 boards for the price of a modern Pi. ESP8266 and ESP32 are also more forgiving with their GPIOs.

Re: Unpopular Opinion: Don’t Use a Raspberry Pi for That

#207

Post by rleigh »

ahepp wrote: post #118
dale_glass wrote: post #75

Earlier quoted context omitted.

There are different kinds of timing issues. There's knowing the time, which you can do with something like NTP. That the RPI can manage just fine. And there's acting with precise timing, eg, if you need to control a mechanism and reliably react on a deadline of a few ms. A RPI doesn't perform well there, which is why 3D printers use microcontrollers instead.

A few ms? In my experience that seems well within the capabilities of Linux. I guess last time I measured wasn't on a Raspberry Pi. I'm kinda tempted to take a shot at profiling this and writing up a blog post since it seems like a useful topic, although it will probably be a few months until I can get around to it.

No, the consistency of the timing is terrible on Linux.

Seriously, stick a scope or logic analyser on e.g. an I2C line and look at the timing consistency. Even on specialised kernels for realtime use, you can have variable timing delays between each transaction on the bus. And this is all in-kernel stuff that's inconsistent--it looks like it's getting pre-empted during a single I2C_RDWR transaction between receipt of one response and sending of the next message. The actual transmission timing under control of the hardware peripheral is really tight, but the inter-transmission delays are all over the place. Compare it with an MCU where the timing is consistent and accurate, and it's night and day.

Re: Unpopular Opinion: Don’t Use a Raspberry Pi for That

#208

Post by paxys »

ar_lan wrote: post #200
paxys wrote: post #170

Earlier quoted context omitted.

This combined with the main article shows the exact reason why Raspberry Pi is as popular as it is. When I'm starting a new project I can either worry about Arduino or ESP32 or other microcontrollers or various NUCs or getting a board fabricated from scratch...or I can grab a RPi from the drawer and know that it will just work, regardless of whether I need to toggle some RGB lights, browse the web, or run a Kubernete…

A 4GB Raspberry Pi 4 costs... $169 USD actively on Amazon ( https://www.amazon.com/Raspberry-Model-2019-Quad-Bluetooth/d... ). I can find more powerful laptops for cheaper. I can get a Dell R720 which has drastically more computing power (32x RAM, much more powerful CPU) for twice the price. RPI used to be economical. If it still cost $50 USD, I'd grab them in a heartbeat to do these types of projects, but as it is,…

Pi Zero 2 costs $15. Pico series starts from $4. There are plenty of cheap options if you don't need the extra power.

Re: Unpopular Opinion: Don’t Use a Raspberry Pi for That

#209

Post by colejohnson66 »

ar_lan wrote: post #200
paxys wrote: post #170

Earlier quoted context omitted.

This combined with the main article shows the exact reason why Raspberry Pi is as popular as it is. When I'm starting a new project I can either worry about Arduino or ESP32 or other microcontrollers or various NUCs or getting a board fabricated from scratch...or I can grab a RPi from the drawer and know that it will just work, regardless of whether I need to toggle some RGB lights, browse the web, or run a Kubernete…

A 4GB Raspberry Pi 4 costs... $169 USD actively on Amazon ( https://www.amazon.com/Raspberry-Model-2019-Quad-Bluetooth/d... ). I can find more powerful laptops for cheaper. I can get a Dell R720 which has drastically more computing power (32x RAM, much more powerful CPU) for twice the price. RPI used to be economical. If it still cost $50 USD, I'd grab them in a heartbeat to do these types of projects, but as it is,…

The RPi starts at $35. The prices you’re seeing on Amazon are scalpers takings advantage of the chip shortage. When Adafruit, for example, has them in stock, they’re at MSRP.

Re: Unpopular Opinion: Don’t Use a Raspberry Pi for That

#210

Post by theodric »

When you're chasing minimum power consumption, tho, a Pi4 (in my case, a CM4) with a 200MHz base clock, a USB3 card, a SATA card with 6 SSDs attached, running 3 Alpine VMs and a couple Docker containers will idle at 12W and perform surprisingly well when asked to while drawing no more than 27W with every system running at full tilt. I didn't expect it to be as good as it is, and I can't find anything else that can touch it. But my use case is narrow and specific.
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