APNIC Box – Linux on a Mikrotik 532a, Part 2 – Hardware Modifications

Follow on from 01 Oct 08 APNIC Box – Linux on a Mikrotik 532a, Part 1

Custom Hardware Modifications

Here’s a labelled image of the inside of the device. You can also look towards the bottom left of the image for my simple solder modifications. Enlarge the image to see the labels.

APNIC Box Image 2

APNIC Box Image 2

1. External 2.4GHz/5GHz antenna. Same on opposite side.
2. 5V solder point
3. 5V connector for miniPCI USB card
4. 2x 2USB Headers. 1 Header in use providing 2x USB interfaces, one to regular host connector for mass storage or other usb connection. Other port for picoLCD on top
5. 512MB CF card
6. miniPCI USB controller

On the underside of the board there is a single miniPCI socket which houses an Atheros 5212 802.11a/b/g miniPCI card. It has two antenna outputs which run under the board and two the two external antennae. I haven’t taken a picture of this but if anyone really wants to see it, I will power down the device, get a picture of it and post it here.


What you’ll need to build you own
I’d really love you to build your own.

1x RB532A
1x Serial female to female cable
1x CF Card (512MB) – get a decent brand
1x PicoLCD plus casing and cables
1x NEC Based miniPCI USB controller (http://www.aaeon.com/PD_Products_Detail_DCCAA0A1DF3344B7BB_928F5E62D5B04DB08D_61FB70F30078430581_TW_utf-8.html)
1x RB532A casing
1x Atheros 5212 based miniPCI wifi
2x RB532A standard 2.4/5GHz omnidirectional antennae (mini snap connector)

Disclaimer: Don’t try and make these simple modifications to your board whereby you solder two wires to two pins. If you do, you will break your board and I can not take any responsibility for breaking your board with anything in this series(!)

Why the soldering?
The soldering is required for the miniPCI USB controller to provide active power to USB devices. The miniPCI socket provides the card itself with 3.3v which it needs to operate. It will work with active (powered) external USB devices with no problem however if our devices aren’t powered such as the USB memory stick plugged into the back USB port, or the picoLCD, then they will not function. USB devices require 5V to power and my electronic load tester showed that combined they didn’t need more than 90mA. I looked at the board for a safe point to draw 5V at ~200mA from. That way we’re sure we’re safe with the current requirements. The PoE connector leads the power pins into a regulator. (One of three small black three-legged components). Googling for this model shows that it was a 5V regulator, that provided sufficient current. We can conveniently access this regulator’s output via the two pins showing next to some jumpers on other pins. The + and GND connect to the USB power input + and GND pins. Great, the passive devices work.

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Coming Next.. Getting Started, Installing Linux

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2 Comments » for APNIC Box – Linux on a Mikrotik 532a, Part 2 – Hardware Modifications
  1. Waseem says:

    Sir I cant get really what this device is capable of, kindly give a brief decription n this as i am very interested in the storage side aspect of this device.
    thanks

  2. Adam Palmer says:

    Waseem,

    What information are you looking for? It’s a reasonably powerful embedded device and it runs Debian with no issue. As such you can use your regular Linux tools and services with no issue. Mine does just about everything a Linux router can do. Your only real constraint is space, and remember that you do NOT want to be writing data to your on board CF card OR your NAND flash as it won’t last for very long if you do.

    That was why I added the USB mod, and can now connect a 500Gb USB hard drive and space is no longer an issue :) .

    I haven’t run a stress test on the webserver but I think the results will be surprisingly good if I do.

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