Page 354 - Hacking Roomba

Chapter 15 — RoombaCam: Adding Eyes to Roomba 335

Internally the SL has two hardware serial ports that are recognized by OpenWrt, but they
operate at 3.3V, so you’ll need a voltage converter if you plan on using them with Roomba or
any other 5V-based system. The SL can be taken apart easily by removing the four rubber feet
on the bottom of the unit to reveal four Phillips screws. Of course, like installing OpenWrt,
opening the box voids the warranty.

FIGURE 15-1: Linksys WRTSL54GS; note the USB port

Installing OpenWrt
Firmware installation on the WRTSL54GS is almost exactly the same as on the WL-HDD.
Both boxes have the boot_wait bootloader that enables you to install (through TFTP) a new
firmware image to it during the first few seconds of it powering on.
Unlike the WL-HDD, which is a very standard Broadcom-based device and thus uses the
generic bcrm firmware, the SL needs a firmware specifically built for it. You’ll still want the
JFFS file system used previously because it enables you to save programs to the flash disk.
Following the naming scheme described in the previous chapter, the firmware you want is:
openwrt-wrtsl54gs-jffs2.bin