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Ask Slashdot: Why Buy a Raspberry Pi When I Have a Perfectly Good Cellphone? 273

Posted by samzenpus
from the expensive-knock-off dept.
scorp1us writes "I've been looking into getting a Raspberry Pi, but I end up needing a case, a display, and some way to power it, and wanting some degree of portability. It seems to me that even the most outdated cellphone has far superior features (screen, touch screen, Wifi, 3g/4g camera(s), battery etc) in a much better form factor. The only thing that is missing are the digital/analog in/out pins. So why not flip it around and make a USB or bluetooth peripheral board with just the pins? I've been looking for this and can't find any, but does anyone know of any in the corners of the internet? I don't care what phone platform."
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Ask Slashdot: Why Buy a Raspberry Pi When I Have a Perfectly Good Cellphone?

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  • Arduino Uno (Score:4, Informative)

    by rwa2 (4391) * on Monday March 25, 2013 @06:27PM (#43276579) Homepage Journal

    Done in one (pun intended)

    Solid, lots of add-on modules, vibrant hacker community. And it has its own programmable processor so if your application permits you don't even have to have it attached to your PC to collect and process data.

    • by gr8_phk (621180)
      He needs portability. The missing piece is a USB I/O board that plugs into your phone. Of course this means having a phone that can be the host device and not just the peripheral.
      • Re:Arduino Uno (Score:5, Informative)

        by SQLGuru (980662) on Monday March 25, 2013 @08:00PM (#43277341) Journal

        With an Android phone, you just need this: http://en.wikipedia.org/wiki/USB_On-The-Go [wikipedia.org]

        Buy one here: http://hakshop.myshopify.com/products/micro-to-micro-otg [myshopify.com] (site might be blocked at some work locations as they might think it's hacking related)

        • by jeffmeden (135043)

          With an Android phone, you just need this: http://en.wikipedia.org/wiki/USB_On-The-Go [wikipedia.org]

          Buy one here: http://hakshop.myshopify.com/products/micro-to-micro-otg [myshopify.com] (site might be blocked at some work locations as they might think it's hacking related)

          This is true, but not all phone hardware OR all versions of Android support USB OTG, in fact only handsets that are less than about 2 years old typically do. Check up on the phone and the compatible software before making any plans. Then, the question becomes is there a particular pre-built APP or even a stable API for working with the hardware I/O and to that I would suspect the answer is no (since the hardware itself is extremely scarce). Bluetooth serial is probably the only thing remotely close to thi

      • by Curtman (556920) *

        The missing piece is a USB I/O board that plugs into your phone

        IOIO-OTG [sparkfun.com]. It costs more than a Raspberry Pi though.

      • Re:Arduino Uno (Score:4, Interesting)

        by Mike Cruse (2876093) on Tuesday March 26, 2013 @03:41AM (#43279157)

        He needs portability. The missing piece is a USB I/O board that plugs into your phone. Of course this means having a phone that can be the host device and not just the peripheral.

        I designed and built several I/O devices like this for myself, well to sell to other people really. The I/O mix for one of my boards is a follows: 4 "Universal" inputs (0-20VDC, Thermistor, 0-20mA, Binary state and 32 bit counter) 4 12VDC @200mA binary outputs 4 One-Wire sensor bus ports (Dallas/Maxim temperature sensors etc) 2 0-10VDC analog outputs RS485 port for multidrop network comms, i.e. Modbus/Bacnet etc CAN port for I/O expansion (multiple boards acting as one on a CAN network) USB device port for either firmware update (mass storage) or USB CDC serial comm port for config, direct I/O control Powered by 12VDC or 24VAC NXP Cortex M3 32 bit processor @120MHZ Primarily intended for building automation but still general purpose enough for many other things. I use then for lawn watering, door bell control, lighting. Has a basic expression parser for interpreted basic logic. Expressions can be stored in flash as can dynamically created user variables. Expressions can also be nested and scheduled for some level of automated behaviour. Everything is accessible via the USB serial connection. The problem is that even my cost for a board like this is many times the price of the cheapest Raspberry PI. But then having very little real world I/O (and large volumes) is how you can achieve a price like that. Anyway, if a phone can interact with a USB CDC device then it could control one of my boards. I am going to have to try that out myself now.

      • by gl4ss (559668)

        he's actually just trolling to someone post links to cheap adk clones.
        http://arduino.cc/en/Main/ArduinoBoardADK [arduino.cc]

        basically it's an arduino that'll act as usb host so you can talk from your android phone to it.
        or you can use bluetooth with some few dollars bluetooth dongle.

        but the thing is, quite easily these solutions start costing more than a raspberry pi costs, so some simplicity and battery use are the advantages against that..

        • by Joce640k (829181)

          but the thing is, quite easily these solutions start costing more than a raspberry pi costs

          You can make one of those with an Tiny85 [atmel.com] and a copy of v-usb [obdev.at].

          Total cost: $1.25 for the chip plus some perfboard and wire.

          If you need more I/O pins, step up to a Tiny84 or even a Mega328 (if you can afford a $3 chip!)

    • Re:Arduino Uno (Score:5, Insightful)

      by girlintraining (1395911) on Monday March 25, 2013 @07:05PM (#43276971)

      Solid, lots of add-on modules, vibrant hacker community. And it has its own programmable processor so if your application permits you don't even have to have it attached to your PC to collect and process data.

      Limited memory, slow I/O, slow processor, can emulate a USB device but can't function at anything resembling modern USB speed... This guy doesn't want another bag on the side, he wants something that gives him a spread of I/O pins and sampling options. And Arduino ain't that -- and he's right, there's nothing on the market that will give him a programmable DAC/ADC paired with a USB controller that can operate at the speeds of the current USB standard (v3).

      It's not hard for an electronics engineer to slap some glue logic and a few chips on a homebrew board and do it, but for a hobbyist who just wants to play? Forget it.

      • Re:Arduino Uno (Score:4, Insightful)

        by chrylis (262281) on Monday March 25, 2013 @07:25PM (#43277107)

        Of course nothing's going to operate at USB v3 Super-Speed. You'd have to be running custom FPGA hardware to get anywhere close. On the other hand, the IOIO seems to be about as close to what the submitter wants as is practical with cheap hardware.

      • Re: (Score:3, Insightful)

        What would a hobbyist that can't handle a few logic chips do with a super fast DAC/ADC? No offense, but this sounds more like a gee-whizz hardware equivalent of a warez dood. You want a DAC ADC combo? It's called a 5$ audio card. If you need multi GHz sampling you can't even begin to do that properly with only hobbyist-level knowledge and equipment. Unless you are into building sub-samplers. But that's a very esoteric niche that long ago broke the multi-100 GHz barrier, so it's inaccessible even for well-to
      • Re:Arduino Uno (Score:5, Insightful)

        by harrkev (623093) <kfmsd@harrelsonf ... g minus language> on Monday March 25, 2013 @10:10PM (#43278055) Homepage

        First, a disclaimer. I am not an Arduino expert. I have one and have played around, but am not a pro. Please forgive me if I make a mistake...

        The big thing is that Arduino does NOT have Ethernet. Yes, you can add it on. I just built a small project for an internet-controlled power outlet. Raspberry Pi + an SD card (around $40 total) is significantly cheaper than an Arduino plus an Ethernet shield (around $60). Plus, the Pi can be programmed in your choice of languages (Python, Perl, TCL, C++, etc.) while the Arduino . Also, a web server on Pi is just an "apt-get" away. Don't get me wrong. The Arduino has its place too. Lots of IO. analog input, PWM output, etc. But the Pi and Arduino are different beasts with different (but somewhat overlapping) targets.

        Now, the concept of using a phone as a general-purpose controller is interesting, if you can overcome the IO problem. If you can find something and cobble it together go for it. However, finding a steady supply of phones would be problematic. I could order a dozen Raspberries or Arduino boards in a moment. Using an old cell phone would require hitting garage sales or thrift stores looking for old phones that actually run something you can use (such an Android). I don't think that you can program older "feature phones." You probably need something with full-blown iOS or Android, and I doubt that an older iOS device is cheaper than a Pi. That leaves Android. If you only need one or two for a particular project, you might be able to swing it. Otherwise, you can't beat a couple of mouse clicks to get a proper development platform delivered to your door for under $50.

  • by Tim the Gecko (745081) on Monday March 25, 2013 @06:30PM (#43276601)

    How about this? - http://www.adafruit.com/products/885 [adafruit.com] - IOIO Mint - Portable Android Development Kit

    • by ntw1103 (1208178)
      1UP. I was just going to suggest this, but you beat me to it. I asked myself the same question, and ended up buying the IOIO board. It works. :)
    • by csumpi (2258986)
      +1. IOIO is an amazing piece of hardware. A whole bunch of io ports, plus your phone already has a screen, storage, battery and reliable wifi.
      • plus your phone already has a screen, storage, battery and reliable wifi.

        That's fine if one's phone is a smartphone running Android. A lot of people especially in the Americas and western Europe carry an iPhone, for which development of accessory hardware is far more expensive. And a lot of other people carry a dumbphone and a separate other device because too many U.S. wireless carriers appear to refuse to activate a voice-only plan on a smartphone: CDMA2000 carriers don't use a CSIM in that country, and some GSM carriers are known to forcibly change the user's plan if the SIM

        • by chrylis (262281)

          If you choose an iPhone, you're knowingly going with a locked-down platform that explicitly forbids hobbyist accessories: "I want to develop an MFi accessory for personal use. Can I join the MFi Program? No." [apple.com]

          The submitter, on the other hand, specifically stated "I don't care what phone platform."

        • by SuperKendall (25149) on Monday March 25, 2013 @07:37PM (#43277171)

          A lot of people especially in the Americas and western Europe carry an iPhone, for which development of accessory hardware is far more expensive.

          Only if you plan to sell it. If it's for personal development, just jailbreak the phone and connect to the serial port pins of the dock connector as per this SO post [stackoverflow.com].

          Obviously anyone looking to build custom hardware can handle the simple task required to hook up to it.

          Optionally of course, you can do anything you like with Bluetooth LE without any licensing from Apple - and commercial apps are allowed to do BTLE communications in the background because of the low power consumption. That's what I would start with as an approach unless you need more bandwidth for some reason.

          • Re: (Score:2, Flamebait)

            by Microlith (54737)

            Yeah, just jailbreak. And enjoy the cat and mouse game with Apple as they try to stuff you back in the box with each update.

            Bluetooth

            Which adds a nice layer of complication to a project.

            No, the answer is to not use iOS devices. Apple obviously doesn't want you to.

            • And enjoy the cat and mouse game with Apple

              A real hacker does not need to update the system the moment releases an update, you can wait a week for the next jailbreak to be found. After all you are doing your own thing right?

              There is no "cat and mouse", Apple generally doesn't care about tethered jailbreaks (which only means you have to have the device connected to a computer when rebooting - I do that about ever six months). Apple only rapidly fixes security flaws relating to untethered jailbreaks (becau

        • by csumpi (2258986)
          Even if you are stuck in the apple lock down, you can buy a used android phone on fleabay or craigslist for under $20. And $20 is not a lot of money if your ultimate goal is to work on some homebrew robotics or electronics project, trust me.
        • For $55, you can get the Redpark TTL Cable for iOS [makershed.com]. More information here: http://www.redpark.com/c2ttl.html [redpark.com]

    • by rwa2 (4391) *

      Ooh, awesome! The IOIO-OTG someone linked to below is the only rev I can find in stock anywhere, though...

      • by chrylis (262281) on Monday March 25, 2013 @06:50PM (#43276845)

        The OTG is the latest IOIO [blogspot.com]. Ytai is still working on crazily trying to pack even more features on the thing (apparently, his goal is to fit in every single sort of IO that the ATmega is capable of), but the OTG is the current state-of-the-art.

        • by chrylis (262281)

          And I've been spending too much time in Arduino-land lately. The IOIO is running a PIC (which can be reprogrammed if you're feeling frisky).

          • by mjwalshe (1680392)
            Yeh have you looked at PIC programing not exatly exactly kid or newbi friendly - and the pi effectively runs the full Linux experience arduinos and mobiles don't and if you can afford a smart phone and is monthly bill you can afford a pi.
            • by chrylis (262281)

              I've programmed PICs in both C and assembly. Anybody who's looking at programming an Android phone in Java should be able to handle basic stuff on one. But there's a reason I put my "if" in anyway.

              You don't appear to have read or understood the OP's question: He isn't looking for "the Linux experience" (whatever that is), he just wants a GPIO breakout box for a phone. The IOIO is that and just happens to be modestly hackable in its own right.

    • by chrylis (262281)

      Came here to recommend the IOIO, specifically the OTG version (which will happily work with a standard computer as a USB peripheral as well). It also has connections for three separate I2C busses, and (unless someone can point me to an existing one), I'm in the initial stages of building an Android app to manually send I2C messages to chips for development purposes.

    • by Nikker (749551)
      How about checking ebay for some used Android phones? If you don't need the screen you can get a bunch of great deals on old nexus/htc phones, otherwise you still find loads of phones for under $50. Do some research on which ones are root-able and have USB OTG and you have some pretty decent flexibility with WIFI, Bluetooth, video out, GPU, dual core, etc,etc.
  • by StealthHunter (597677) on Monday March 25, 2013 @06:32PM (#43276629)

    If your use-case is "leave attached to my TV" then a Pi makes a lot of sense. If you want to have a resilient case, be portable, have a small screen attached, etc, then maybe a phone makes more sense.

    • Another thing to consider is the community. Using some random phone, may have a small to medium sized community built up around hacking it. The Raspberry PI has a huge community built up and continuing to build up around it.
      Also the phones cheep enough for hacking tend to be ones that are out of production, so getting another one, 6 months down the road may not be easy.
      I am a fan of the Raspberry PI, but that doesn't make what I have written wrong.
    • Well, I have a RPi and a MK802, and the MK802 ends up being cheaper for this use case. The cost of the Pi, plus cable, sd card, a case, and the HDMI cable ends up being higher than the MK802. And the MK802 runs Android, meaning lots of apps ready to use. For me, the RPi is a cheap home server. And even on that use case, the MK802 with Linux is a better machine
    • by Pseudonym (62607)

      This.

      The features of a Raspberry Pi are:

      1. It doesn't come with a battery, wifi, GPS, screen etc. You only pay for (in both price and power consumption) the features you need.
      2. It's really cheap. This means that you can destroy it and not feel bad about it. You can't say that of your mobile phone.

      If what you actually want is a PDA with custom peripherals, then your perfectly good mobile phone may well be perfectly good. If you want something else, then a Raspberry Pi or Arduino may be better.

    • by Osgeld (1900440)

      it doesnt make a ton of sense there considering you can get android sticks that work out of the box that do everything a TV packed pi does after fucking around with it

  • by mr_goodwin (220609) * on Monday March 25, 2013 @06:34PM (#43276659)

    I'd have had trouble doing this with a cellphone:

    https://www.youtube.com/watch?v=m_c9cxoM8tg

    Part of the usefulness of the Pi is *because* it lacks those things; you have the option of adding what suits your application.

  • I don't see what the point of this claim about the "most outdated cellphone" was. Even among new phones, there are models without touchscreens or wifi, and if you start considering outdated technology at all then your claim becomes even more inaccurate.

    • by hawguy (1600213)

      I don't see what the point of this claim about the "most outdated cellphone" was. Even among new phones, there are models without touchscreens or wifi, and if you start considering outdated technology at all then your claim becomes even more inaccurate.

      Using my keen powers of recognizing context, I've deduced that he meant "Android smartphones", he wasn't talking about a basic feature phone that doesn't run android and doens't have a screen, touch screen, Wifi, 3g/4g camera(s), etc.

  • by BitZtream (692029) on Monday March 25, 2013 @06:37PM (#43276687)

    An Arduino will get you pretty close to a box with pins attached to a USB cable, though the USB cable is emulating a serial port.

    A Raspberry Pi is like an original iPhone with the screen removed a few ports added and all the Arduino GPIO features built onboard so you get GPIO support built in.

  • For a little scada type application. You probably could do what you want to do, but the easiest way to do it would be to make it connect to the phone via bluetooth. It seems that you can't just connect things to the USB ports on a phone and access them the way you think you could. But if you use bluetooth, it's one more wireless point of failure and you have to look at getting power to your board instead getting it from the phone. Didn't appeal to me and just dropped this idea.

    More open access to the usb po

  • Peripheral boards (Score:4, Interesting)

    by RabidReindeer (2625839) on Monday March 25, 2013 @06:46PM (#43276815)

    "I've been looking into getting a Raspberry Pi, but I end up needing a case, a display, and some way to power it, and wanting some degree of portability. It seems to me that even the most outdated cellphone has far superior features (screen, touch screen, Wifi, 3g/4g camera(s), battery etc) in a much better form factor. The only thing that is missing are the digital/analog in/out pins. So why not flip it around and make a USB or bluetooth peripheral board with just the pins? I've been looking for this and can't find any, but does anyone know of any in the corners of the internet? I don't care what phone platform."

    I think this might be adaptable. Although its original intent was as an XBee interface, the catalog explicitly states it can be used for USB-to-TTL. Presumably by tapping the points where the ZBee's GPIO pins break out:

    http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2159285_-1 [jameco.com]

  • by tuppe666 (904118) on Monday March 25, 2013 @06:48PM (#43276831)

    I'm not sure why the comparison with a cellphone. Currently I'm using it as XBMC and using my Android phone as the remote. It was a toss up between the Pi and the ultra cheap AndroidTV dongles that are kicking around (Why I think AppleTV is dead on arrival), and overall I couldn't be happier stupid setup errors aside [power supply too weak on the pi to power the usb; couldn't get wifi working on the minimal distribution?] Otherwise its incredible, and using the phone as a remote control has changes my life.

    There are a few compromises with the pi [512 memory & missing sata] otherwise I'm overjoyed with the source. Killer feature, you mess up you wipe your card and your good to go.

    The bottom line is your old phone is less versatile with less support, but its great at being a phone...which if its the task you want go ahead. Otherwise its such an incredible strange question.

    • by macshit (157376)

      The bottom line is your old phone is less versatile with less support, but its great at being a phone...which if its the task you want go ahead. Otherwise its such an incredible strange question.

      I think it's not really an unsurprising question though. Highly functional phones are relatively new (especially in the U.S.) and thus very fashionable now, and have sort of come to occupy a mental slot as the "do everything solution"—even though they're actually pretty bad for many tasks.

      In some cases, of course, the poorer functionality of a phone-based solution is acceptable, and using a device one already has offsets the problems, but I think even in cases where this arguably isn't true, people

  • It regularly manages to crash the USB stack if you put load on the USB stack, so considering that the LAN on the RaspberryPi B is connected to said USB...
  • by hamster_nz (656572) on Monday March 25, 2013 @06:52PM (#43276867)

    You should look at the other ARM boards out there e.g. pcDuino [pcduino.com]. More memory, more I/O, onboard flash, Linux or Android.

    However there are some things that you can do with a micro-controller that can not be done with a full OS - e.g. bit-banging I/O to one-wire temperature sensors. I've even used a full USB 1.1. HID driver implemented completely in software, which would be impossible with an full OS running!

    • by Dahamma (304068)

      However there are some things that you can do with a micro-controller that can not be done with a full OS - e.g. bit-banging I/O to one-wire temperature sensors.

      Why couldn't you do that with a full OS? I did something just like this under Linux almost a decade ago on a set-top with BRCM SoC. You can even do it in userspace if you mmap the BRCM GPIO registers. Same with a HID driver (BRCM's was implemented in software in a kernel module... kind of a CPU hog, but it worked fine). Even their V.34 modem wa

  • by techhead79 (1517299) on Monday March 25, 2013 @07:07PM (#43276975)
    Because one of them doesn't actually cost 35 bucks to produce.
  • If all you want is a USB and a bunch of pins with it, then the Raspberry Pi is overkill where a simpler microcontroller board would do.

    One example of such a board is the Teensy 3.0 [pjrc.com] USB Development Board. It has a 48MHz ARM cpu (Cortex-M4), is only 1.4 by 0.7 inch large, has 28 pins and a micro USB port.
    By default, it gets its power from a host computer, but you could also wire up its own power supply. There is also an optional Micro-SD card board for storage.
    However, I don't think that it would run Linux li

    • by lenski (96498)

      Teensy would be tempting to anyone who has already done embedded development in the ARM microcontroller world. Insufficient memory to run any Linux, but plenty of flash and RAM to run any of many deeply embedded RTOS. Looking over the reference manual shows that the chip's peripheral blocks are powerful, including what appears at first read to be a pretty snazzy DMA controller.

      I've been seriously considering it as a target for developing a communication front-end for a project at work. Previous experience i

  • It makes sense to use RPi when you need ALL of these:
    1. Linux toolchain and lots of available packages (open source)
    2. Develop on the device itself
    3. Once the application is ready, disconnect screen/keyboard and use remote SSH if necessary
    4. Low cost

    The cost of an USB IO expansion board is typically higher than RPi.

  • by davydagger (2566757) on Monday March 25, 2013 @07:45PM (#43277217)
    1. price- no cell phone is that cheap
    2. better documented hardware with FOSS drivers.(NO cellphone has FOSS drivers, or firmware). In fact its hard if not impossible getting firmware extracted, or proprietary binary drivers for a general purpose OS for your cell phone.

    Its not like desktop OSs, where you can just download the latest nvidia or ATI drivers for linux from the vendor

    3. Cell phones are made for android which is NOT a General Purpose OS, and can be restrictive.

    4. Rasberri PI by default boots from an SD card, making running whatever OS you want, without hacking easy. There is also no need to root it.

    5. the Rasberri PI also has hostmode USB ports, for plugging devices in, your phone most likely does not, if your lucky OTG.

    6. There are other ARM protoboards and dev boards that are not the PI which have ARM class CPUs. Most of them run any OS you put on them. RasPI is not the first nor will be the last.
  • http://pyvideo.org/video/1668/keynote-2 [pyvideo.org]

    Maybe you'll still feel like the Pi isn't for you, but contrasting the Raspberry Pi against a cell phone is missing the point entirely, and it detracts from the purpose of the project.

    • by scorp1us (235526)

      No, I'm not. I understand what the Pi is, But my point is that is if far better displaced by a used cell phone. How many people do you think are passing over a 1g to buy new hardware with less bells and whistles?

  • by inglorion_on_the_net (1965514) on Monday March 25, 2013 @07:59PM (#43277335) Homepage

    Why Buy a Raspberry Pi When I Have a Perfectly Good Cellphone?

    Because you can install your own operating system on your Raspberry Pi, but not on your cellphone?

    Because you want to support the Raspberry Pi foundation?

    There are many possible answers.

    It seems to me that even the most outdated cellphone has far superior features (screen, touch screen, Wifi, 3g/4g camera(s), battery etc) in a much better form factor.

    If the combination of those is what you're looking for, then maybe you want a cellphone. Why are you comparing a cellphone against a Raspberry Pi?

    The only thing that is missing are the digital/analog in/out pins. So why not flip it around and make a USB or bluetooth peripheral board with just the pins? I've been looking for this and can't find any, but does anyone know of any in the corners of the internet? I don't care what phone platform.

    What are you going to do with it? How are you planning to do it? You don't care what phone platform? Don't you at least want one that you can run your own code on? Preferably with enough privileges that you can actually drive your shiny peripheral?

    Here's the thing: Tell us what you're trying to do, and maybe we can help you, possibly by giving some recommendations for hardware to work with.

    As it stands, your question is more flamebait than helpful. You're stating that you think even outdated cellphones are superior to a devices that some of us really like, without stating what purpose you think cellphones are superior for. That gives us little opportunity to be helpful, and plenty of opportunity to feel slighted.

    • by scorp1us (235526)

      You've got the best reply by far. I think you hit on a really good point - the operating system. With a Pi, I'm running standard linux. With Android/iOS I'm using their SDK. It could be good or bad. It's somethign to learn.

      I'm comparing it against a RasperryPi because I'm aware of the Ardruino and the Pi and they are made for the hacking community. But the cellphones aren't and given the fact that we're returing these devices every two years there is a _HUGE_ market of very capable hardware out there.

      I have

      • by chrylis (262281)

        To be fair, the blame regarding OTG lies mostly with Intel, which explicitly designed USB to be a master-slave protocol (requiring a host PC) to compete with FireWire, which is peer-to-peer and has a layer 2 that looks more like Ethernet. OTG actually does put the phone into host mode, but there's negotiation required so that the phone knows which state it's supposed to be in and two OTG-capable gadgets can still operate correctly with OTG-oblivious hosts.

      • You've got the best reply by far.

        You honor me. *makes a bow*

        I think your idea of taking advantage of hardware that you already have or can cheaply obtain is a great one. And if you need GPS, WiFi, and a display, some cellphones will give you all these out of the box, whereas the Raspberry Pi won't. So if your choice is between a $1 device plus a $5 add-on, or a $25 device with probably much more expensive add-ons, it seems like a no-brainer.

        So let me as you this, wouldn't it be far better for you to get the IOIO and an Aria for your projects?

        For your projects, this would seem to be the case. For what I do (hosting website, software developm

  • For me, the grand appeal of the Rasbperri PI is it's 26 I/O lines--It's difficult to find a microcontroller with so many I/O lines and particularly with any reasonable CPU power.. This provides both. The downside is that the gyros in smartphones are also very useful in robotics projects. And I'd sure be nice to also have access to some GPU power, computationally...

    • by Osgeld (1900440)

      the big problem with the I/O lines is it goes though a huge OS so doing simple things like i2c is challenging

      its fine if you want to flicker a led

  • The Redpark TTL Serial Cable [makezine.com] connects iOS devices to TTL serial devices. So you could hook it up to an Arduino. Except the cable itself costs more than a Raspberry Pi...

  • by Miamicanes (730264) on Monday March 25, 2013 @09:29PM (#43277863)

    Does anybody know of any widely-available Android phone that directly exposes 2 or more GPIO pins via some usable-connection point, like the headphone jack or Samsung USB port pins (via some officially-nondocumented WDC USB crossbar-chip setting or resistor value)?

    I know some phones expose a UART (with nonstandard levels) on the headphone jack (Original G1) and repurposed usb pins (original Galaxy S?), but I've never come across a real reverse-engineered schematic for the HTC HeroC, Samsung Galaxy S/Epic4g, Motorola Photon (as if it would matter, since the evil bastards permalocked the bootloader & ruined it), or Krait/US-variety Galaxy S3 that shows what's sitting between the headphone jack & SoC and what the jack is physically wired to inside.

    The big prize: if the 3 headphone jack pins (plus gnd) are connected to real gpio pins (normally tristated, or even directly-driving/sampling the headset)... THEN bitbanged SPI becomes possible. A real UART is a distant second consolation prize, moving up a notch if it can do Atmel-like 1mbps and/or 9-bit serial. I2C would be cool, but I won't hold my breath. DMA-able ADC (== mic) and DAC (== audio out) would be nice IF they aren't forcibly intercepted by a codec chip that can ONLY do mp3 &| audio-bitrate P[W|C]M.

    As others have noted, IOIO is great, but USB limits you in some serious ways if you're trying to do raw realtime bitbanging. The main problem with USB is that it basically forces you to move your realtime logic to dedicated hardware at the other end of a USB cable (like ioio, or an AVR-based ADP. A Raspberry Pi gives you directly-bitbangable gpio. AFAIK, no Android phone does.

  • I don't care what phone platform

    AFAIK there is no JS API for I/O pins, which means it has to be handled by a native app. On iOS you cannot run your own apps, except if you root the device, therefore I would say that one care about the platform: iOS is not hack friendly

  • by pcjunky (517872)

    Why do I need a screwdriver? I have a hammer.

  • you need 100 of them?

    You can't exactly go out and buy 100 cell phones -- at least not at the same price point as the raspberry pi's.

  • if you want to frob around with something, an old Android phone is a pretty good platform. But if you want to create something that can be reproduced and extended by others, then you need something which is in production *now* and into the reasonably foreseeable future. If you want to teach about technology from the ground up (the primary purpose for the project), and courage a take-it-apart-redesign-it-and-put-it-back-together approach to learning, you want something packaged as parts.

    I've mucked around

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