The slammed webcam: An impromptu teardown
At the time, I thought I’d fixed the issue by downgrading the new router’s 2.4 GHz band configuration from "mixed" to "802.11b/g only" and by downgrading its encryption from "WPA2 Personal" to "WPA Personal." But while away on a subsequent trip, I unfortunately discovered that I was unable to access the webcam from the road via the WAN. Upon returning home, I found that the still-lit blue "power" LED on the front of the unit was no longer accompanied by an illuminated red "activity" LED. Power-cycling the TV-IP400W resurrected its connection to the network, but only temporarily … each time I did, the wireless tether would randomly drop again a few minutes/hours/days/weeks later.
I could have just given in and bought a newer replacement webcam; TRENDnet’s TV-IP551W and TV-IP751WC have both been promotion-priced at less than $40 recently, for example. But neither of these units offers the TV-IP400W’s horizontal and vertical "swivel" features. And after all, why spend $40 when you don’t have to? So I’ve instead been Ethernet cable-tethering the TV-IP400W to a spare HomePlug AV powerline networking adapter. This alternative connectivity scheme has proven to be rock-solid (at least when premises power is up, that is). But it’s still not perfect.
The TV-IP400W is sitting on a window ledge that’s no deeper than the camera itself is. Both the Ethernet cable and the power cord hang down from it to a power outlet below and to the left. And it’s right by the front door, where the dogs excitedly congregate each day when it’s time for a neighbourhood walk or a drive to the nearby dog park. Every once in a while, one of the dogs bumps up against one or both of the cables. And every once in a while (twice so far, to be precise, as I recall) when that happens … the camera falls to the slate floor below.
After the most recent iteration of this particular loud-crash calamity, I picked up the camera from the ground, power-cycled it, happily noticed that it went through its usual turret-oscillation power-up sequence, and thought nothing more of it … until I went back on the road, and once again realized that I was once again unable to access the webcam via the WAN. Returning home and perusing the TV-IP400W front panel, I saw a completely different pattern; the activity LED would blink once for a comparatively long duration, then nine times for a shorter per-blink duration, and then repeat the one-then-nine sequence over and over again.
This pattern was undocumented, and I feared I’d done permanent damage to the unit. But I’d always been curious to know what components were inside the device, so I decided to "turn lemons into lemonade" and do a teardown both to satisfy my curiosity and educate all of you. Upon removing the camera’s bottom cover, I discovered that the impact of the TV-IP400W hitting the floor had dislodged one end of its Wi-Fi mini PCI add-in module from the mating socket.
Reinserting the module and powering the camera back up happily resulted in it going back online.
Even though I’d been using the camera’s wired Ethernet port, it makes sense that a malfunction in the Wi-Fi subsystem (which shares the wired Ethernet transceiver’s MAC address, therefore the router’s DHCP-assigned IP address) would bring the entire system down.
While I had the bottom cover off, I decided to continue my disassembly to see what else interesting I might discover. Here’s the back of the Wi-Fi module, which is based on Ralink’s RT2560F transceiver
Here’s one side of the main system board, after removal of the Wi-Fi module.
And here’s the main system board’s other side, containing the bulk of the camera’s silicon content.
ICs you’ll discern on the board include:
Eon Silicon Solution’s EN29LV160AT-70TCP 16 Mbit boot sector flash memory
Hynix’s HY57V641620FTP-6 64 Mbit SDRAM
RDC Semiconductor’s R2886-G Fast Ethernet RISC processor
Realtek’s RTL8201CP Fast Ethernet PHY
SyncMOS’s SM5964 8051-compatible microcontroller, and
Rohm’s BD6758 stepping motor driver