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I want to get started with embedded development and for my first project I thought of making a caller-ID type of appliance.

Here's why I want a SBC for this:

  • I want to be able to locally serve this data (i.e., caller log) via HTTP
  • I thought of maybe extending this appliance and adding an answering machine of some sort at a later time, so I guess I'll need "advanced" modem capabilities

From what I understand, all I really need is a SBC and a USB modem.

Can someone recommend the cheapest and most lightweight SBC that would be able to fulfill these requirements?

EDIT: This board looks cheap enough. Though it's only the "brains" of what I'm after. How hard would it be to hook up OEM ethernet, USB, and serial connectors to something like this?

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  • \$\begingroup\$ USB modem? I would bet you could find a top-notch RS-232 modem on the used market from US Robotics for a great price. Their modems implemented virtually all the AT commands and would certainly do the trick. \$\endgroup\$
    – J. Polfer
    May 13, 2010 at 0:09
  • \$\begingroup\$ What OS does the board need to run? \$\endgroup\$
    – J. Polfer
    May 13, 2010 at 0:11
  • \$\begingroup\$ Re: OS -- I don't care about the underlying OS, really. Though, I suppose I'd prefer some flavor of Linux as a learning platform. \$\endgroup\$
    – jfl207
    May 13, 2010 at 3:15
  • \$\begingroup\$ Re: Modem -- Would I be able to use an RS-232 modem to implement something like an answering machine? Any limitations on the telephony APIs I can use in general with such a modem? \$\endgroup\$
    – jfl207
    May 13, 2010 at 3:15
  • \$\begingroup\$ I'm pretty sure you won't be able to do recording over RS232, as would be required for answering machine functionality. If you want it to take messages, you need to be certain to get a modem which can also make voice calls. Some can, some cant. \$\endgroup\$ Feb 4, 2011 at 0:32

3 Answers 3

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I'd say you'd want a cheap embedded Linux board, like the Technologic Systems TS-7550: http://www.embeddedarm.com/products/board-detail.php?product=TS-7550

I used one recently to make thermostat for my house that serves up temperature data via HTTP.

I'm not sure what to recommend on the modem side of things.

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  • \$\begingroup\$ what linux did you use on that? \$\endgroup\$
    – JustJeff
    May 12, 2010 at 2:29
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    \$\begingroup\$ @jfl207: Thanks. The thermostat code is on Github if you're interested: github.com/pingswept/thermopyla/tree/master/thermo and you can see the one public page that the thermostat serves here: thermo.pingswept.org:8080/thermolog I hadn't seen the mini2440 before; it looks like a pretty good choice. They don't appear to have any distributors in the US, but I assume that's just my problem. \$\endgroup\$
    – pingswept
    May 12, 2010 at 3:22
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    \$\begingroup\$ @jfl207: That board looks great. Getting a serial port to work with that will be straightforward, and USB will probably not be too bad. Ethernet might be harder-- it looks like there is no Ethernet PHY on the board. (The PHY is the chip that translates from the Linux MII driver, which is a 4 wire, 25 MHz bus, to Ethernet, which is 2 differential pairs, 125 MHz, MLT-3 encoded, blah, blah, blah.) The other question is how you will connect to the board. It's not clear to me that it will plug into a breadboard, as it looks like it has double-row headers. That would mean you have to make a PCB. \$\endgroup\$
    – pingswept
    May 12, 2010 at 12:37
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    \$\begingroup\$ (Ran out of characters in that last comment.) The point is: you're probably better off paying the additional $30 for the SDK, unless you want to lay out a PCB yourself. That's certainly a viable route, but only do that if you want to. You say this is your "first project"; I think it might be ill-advised to try a PCB with Ethernet on your first go. \$\endgroup\$
    – pingswept
    May 12, 2010 at 12:41
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    \$\begingroup\$ Take a look at Gumstix, the Beagleboard, and the Hawkboard. The Hawkboard was just released recently, and it's quite cheap. \$\endgroup\$
    – pingswept
    May 12, 2010 at 12:58
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Just use an old computer that can run Linux. No reason you can't do embedded development on a PC; I do it at my day job all week long.

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  • \$\begingroup\$ Try a BeagleBone, they have lots of I/O and a good support community. You could probably add your modem as a simple serial device on your own "cape" (i.e. plug in board). \$\endgroup\$ Jun 4, 2014 at 20:05
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This PhidgetSBC2 board has everything you need, including a full Debian Linux distribution (allowing you to add whatever packages you would like).

Only downside is it is a bit more expensive.

http://www.phidgets.com/products.php?category=21&product_id=1072

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