Thread: Been looking in all the wrong places for an embedded Linux computer

For a while I've been wanting a super cheap Linux computer with basically an ethernet port and a USB port. I had spent so much time looking at the Raspberry Pi, BeagleBoards, etc etc. While they all have nice features, they're not my idea of super cheap. The Raspberry Pi is $35, but you really need an enclosure and a power supply/cord, so it's more like $45 at least (I'm a cheapskate, I know). Even then, community support for everything except the Pi is questionable.

Anyway, after some googling I finally found more of what I've really been looking for: OpenWrt. I had run across it many times before, but it never really clicked that you can load up OpenWrt on a router and then use it for general purposes instead of strictly networking.

I'm going to use it for a special project here at work where we basically need to log the serial data coming over an RS485 line. I'm going to buy a $20 D-Link DIR-505L router (already enclosed and has a built-in power supply, UL listed too!), a cheap USB hub, and a cheap USB thumb drive. We've already got a USB to RS485 serial converter dongle, all I have to do is hook it all together. Once I install OpenWrt, all I have to do is (famous last words) install the appropriate packages for USB mass storage device support and USB-serial converter support. Then I can put a script in the init.d folder to basically cat /dev/ttySx > /media/thumb_drive/raw_data_file. Voila. And I'll be able to retrieve the data remotely via scp.

All the dev boards definitely have their advantages (more CPU/RAM) and different purposes (I/O besides USB), but I think it's pretty frigging cool to buy a $20 travel router like the DIR-505L and get: enclosure, power supply, ethernet, wifi, USB, and an easily installable/available Linux firmware image.

www.openwrt.org

It's exactly what I've been looking for. It gives me a somewhat 'exotic' platform to program on (MIPS24Kc), and yes, a full-featured Linux computer for $20. Most of my projects center around needing the flexibility that a normal PC environment provides, and any I/O (which is minimal) can be provided through USB. Also, in this case, having something that is UL listed is critical, so routers win.

I do like the Arduino, I used it in school to control a compressed-air-powered piston engine my team built: https://www.youtube.com/watch?v=3FeJYZ-i0OY

Not a fan of the RPi because of the ARMv6 architecture.

Originally Posted by Epy

All the dev boards definitely have their advantages (more CPU/RAM) and different purposes (I/O besides USB), but I think it's pretty frigging cool to buy a $20 travel router like the DIR-505L and get: enclosure, power supply, ethernet, wifi, USB, and an easily installable/available Linux firmware image.

I am actually wondering how I could harness all this CPU/RAM to manage a network as one of my fancy projects.From what I have heard using PI for network management slows down the network.

"Sometimes", I needlessly "enquote" everything, "too".

Pleasantly surprised.

Everything went smoothly, bought the router, flashed the firmware, installed some packages and got the serial piped to a file no problem. The only hiccup I had was that the D-link emergency flash firmware page only works with IE, and also that I failed to read part of a guide concerning SSH refusing some connections. There was a kernel module issue for one off-brand USB-serial converter as well. All in all though, pretty smooth experience.

Yes, funny story, when the SSH server did not come up as expected several times (nothing to do really, after you set the root password through telnet, telnet is disabled and SSH is enabled), the router spent the night in my kitchen garbage can before I decided to give it another try this morning.