New Raspberry Pi board has lower power consumption, price

The Raspberry Pi Model B is one of the most appealing mini-PC boards on sale right now. For only $35, you get an ARM-compatible Broadcom SoC, 512MB of RAM, dual USB ports, an SD slot, HDMI output, and Ethernet support all on a tiny circuit board that measures about 3.4″ x 2.1″. The Model B has been shipping for a while, and it’s finally being joined by the Model A. This newer version has started rolling off the production line and should be available for purchase early next year.

While the Model B came first, the Model A is the one that delivers on the Raspberry Pi group’s promise of an ARM-based Linux PC for $25. This version costs 10 bucks less than the Model B, and it drops a few features. There’s only one USB port, the amount of onboard memory has been halved to 256MB, and the Ethernet chip is gone. These changes cut the power consumption by more than 50%, an apparently important consideration for some users. The Raspberry Pi folks say there’s demand for the Model A among roboticists, people doing industrial control and automation work, and even consumers building uber-cheap media systems.

I’ve been tempted to build a basic media box using a Raspberry Pi board combined with XBMC, which has been ported to the platform. The Model A’s lack of Ethernet support definitely limits the options for streaming content, though. The Model B is still incredibly inexpensive considering the capabilities, and at 3.5W, its power rating is still pretty modest.

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    • Kurlon
    • 7 years ago

    The lack of Ethernet on the Model A isn’t really a limitation compared to the Model B. Ethernet on the Model B is USB based, so you’re still limited by the horrible USB controller Broadcom went with for this SoC no matter which way you go to secure connectivity.

    • chuckula
    • 7 years ago

    [quote<]These changes cut the power consumption by more than 50%, an apparently important consideration for some users. [/quote<] If I had a project where the whole system was being powered by solar cells + batteries, then the reduction in power usage could be very helpful. In the more standard configuration where the system just receives power from a USB charger / PC port, it doesn't help as much. IIRC, it is technically possible to power the Raspberry Pi with a direct DC current, which might be more efficient than going through the USB port when you really need to save every last milliwatt of power.

      • siberx
      • 7 years ago

      The Pi includes a small 3.3V regulator for the SoC itself (it’s linear, I believe, so not *particularly* efficient) but it’s just fed straight 5VDC over the usb plug. Externally, making that 5V as efficiently as possible will obviously help you but beyond that if you want to maintain full functionality (working USB port) you can’t power it any more *directly* and have it still work.

      If you happened to have an efficient 3.3V regulated source already in your system you could probably drive the main bits of the Pi with it directly, assuming you were just interested in the microcontroller and its GPIO header or other directly-interfaced connections.

        • willmore
        • 7 years ago

        I’ve not looked at the schematic, but I have trouble believing that a modern SoC really runs on 3.3V. Maybe it uses it for I/O and a separate supply for core? Heck, even years back the Philips LPC 2xxx chips used 1.8V for their core.

        If you really need as low of a power consumption as possible, make sure you replace all of the linear regulators with switching ones–unless the quiescent current is very low, then it might pay to use a really good linear regulator.

      • delsydsoftware
      • 7 years ago

      When I first got my Model B pi, I didn’t have my usb charger handy. I ran it off of a Vaas portable USB charger, which is just a huge 5000maH lithium ion battery with a couple of USB ports. I was able to get hours and hours of usage out of it, and the battery still hadn’t run out. I bet the model A could run for 24 hours or more on that battery pack.

    • chuckula
    • 7 years ago

    [quote<] people doing industrial control and automation work[/quote<] As a Raspberry Pi early adopter (my model B rev1 only came with 256 MB of RAM), let me tell you something: This board is not fit for use in any real industrial control or automation environment!!! I think the fact that smoke came out of the board the first time that I plugged in the HDMI cable would give pause to anyone who wants to use the Raspberry Pi outside of a hobby or education context. (The board survived the smoking incident BTW, and it powers my in-house temperature logger here: [url<]http://habeas.homelinux.org/hourly.svg[/url<]) I think the Raspberry Pi is a great project and the boards are fun to play with, but unlike some of the people in the "community" for Raspberry Pi, it isn't the be-all end-all solution, and it wasn't even the first product to get Linux running on an ARM board for hobbyists and education (see Beagleboard & Beaglebone).

      • Narishma
      • 7 years ago

      Maybe you’re just unlucky and got a faulty board?

      • Deanjo
      • 7 years ago

      Been using 5 of them in and industrial environment just fine. You are basing you assessment on one (potentially bad or user oversight) incident. I can’t tell you the times that I have seen brand new “industrial grade” controllers die upon power up over the years.

        • chuckula
        • 7 years ago

        1. While industrial grade boards can certainly die (anything can die), the manufacturing tolerances, fusing, grounding, etc. are much much better in real industrial electronics.

        2. In a *real* industrial environment (and I don’t mean your own farm here), a big component in getting “industrial” grade electronics is that there is either support or someone to sue if things hit the fan. Good luck getting anything like that out of the Raspberry Pi people, despite whatever advertising they put on their site.

        Once again, the Raspberry Pi is a fun project, but when people exaggerate what it really is, they aren’t doing anyone any favors.

          • Deanjo
          • 7 years ago

          FYI the environment that they are being used in is one of the most hostile there is (and no I’m not talking about a farm, I am talking about a fibreglass plant). The pi is just as capable, as any industrial controller out there. Your point of weakness will more then likely be your interface design. The utilization of the GPIO is no different on the pi then any other “industrial” controller. BTW it is extremely rare to sue the manufacture of an industrial product, the design engineering firm of your setup perhaps. Industrial != critical system.

            • chuckula
            • 7 years ago

            So GPIO pins on industrial boards are never fused? Because there are no fuses on the GPIO pins on the Raspberry Pi, so I’m assuming you think of those boards and the systems they support as completely expendable in the event of a transient.

            We may have different definitions of “industrial control system”. When I hear that term, I’m thinking big-time systems that have to work right or at minimum there is a big loss of money and at a maximum a big loss of life. I think you have a different definition in mind, in which case the Raspberry Pi might be nice for some systems, but is by no means for every use.

            • Deanjo
            • 7 years ago

            GPIO pins can be fused on the pie as well. In fact any good expansion board design includes them and if you don’t well you just designed a piss poor expansion. The beautiful thing about the pie is that it is so inexpensive it is easy to carry replacements on hand if uptime was critical.

            • yogibbear
            • 7 years ago

            Can you please let us know what the function of the Pi is for your fibreglass plant Deanjo?

            I mean… is this thing exposed to the weather? Is it subject to potential fires/gas releases? What is the moisture/humidity in the area? What backup systems and alarms does it report to? Where is it in the control system hierarchy?

            • Deanjo
            • 7 years ago

            Right now they are being used for two purposes. Flow control of the resin and catalyst and strand monitoring. Full redundancy, all systems report back to an out of plant monitoring server. The environment is an extremely flammable environment (as are all fibreglass plants) and the pi’s are all in fire rated enclosures.

            • yogibbear
            • 7 years ago

            1.i) Is this plant operated in batch mode?
            ii) Or is it continuous?
            2. Is there an independent system that alarms on high/low flow of the resin and catalyst?
            3. What action is taken upon alarm, is it a unit/plant trip?
            4. What is the failure safe position for your operation when these Pi controllers all go down?

            • Deanjo
            • 7 years ago

            1) Is this plant operated in batch mode? batch
            2) Is there an independent system that alarms on high/low flow of the resin and catalyst? That is what the pi’s are doing. They are the independent monitors
            3) What action is taken upon alarm, is it a unit/plant trip? Shut down of flow in that section
            4) What is the failure safe position for your operation when these Pi controllers all go down? Flow stops.

            • yogibbear
            • 7 years ago

            Seems safe enough to me then. (Not knowing the plant, hazards, etc.)
            Only thing that would be on my mind would be… what indication is there that it is the Pi controllers that caused the trip? Is it just in the control system / alarm logs?

            What I couldn’t comment on (and why I typically do buy the stamped/rated stuff) is reliability. But if you’ve got a bunch of them acting in a backup arrangement and you aren’t concerned about plant availability.. then it’s OK.

            Typically with something like this… I’d see over the long term the reliability becoming a nuisance (more so due to environmental conditions), the operators bypass the controllers and switching to manual… and then something goes wrong. If you are good with the reliability / you’re the operator and know how to fix these when they stuff up, then I guess you’re OK with it and you won’t switch it to manual.

            • Deanjo
            • 7 years ago

            Any good industrial setup has redundant systems in place to deal with time critical failures. Redundancy is the key to maintaining availability.

            Heartbeat monitors and remote logging easily indicate where a when and failure has occurred. That is more then what most “industrial” solutions provide.

            • Washer
            • 7 years ago

            Is this some kind of joke? Trolling? You can’t be serious…

            • Deanjo
            • 7 years ago

            A poor mechanic blames his tools. A good mechanic makes the tools work for him.

            • Washer
            • 7 years ago

            Exactly. You’re the idiot mechanic choosing the wrong tool.

            • Deanjo
            • 7 years ago

            It can’t be the wrong tool if it does the job exactly as it is supposed to.

            • ermo
            • 7 years ago

            I’m curious, but how long are you expecting the boards to last? How are the boards fed juice?

            Having owned a few embedded routers in my time (the broadcom MIPS based ones that ran OpenWRT when it was still just an embedded router platform) and having installed them in a business setting, I know that the boards themselves tend to keep working, but the power bricks might not hold up so well over time…

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