Teardown: A Wi-Fi smart plug for home automation
The TP-Link HS100 dissected here, which I bought on sale for $19.99 from Newegg back in April, is conceptually similar to the base Belkin WeMo Switch. And like the Belkin WeMo Insight Switch, the TP-Link HS110 upgrade adds energy monitoring capabilities.
I'll begin, as usual, with some external packaging shots:
Slide the top off the box and the first thing you see is the GPL notice. Good (open-source support) for you, TP-Link!
More generally, here's a shot of the included documentation stack:
Here’s a look at both sides of the quick-start guide:
Underneath the documentation stack is the switch itself and its backside:
And a closeup of the sticker found there:
As you can see, there's a seam along the sides, but no amount of "crowbar" (flat-head screwdriver) insertion and elbow grease convinced the two halves to part. I then realized there was a Philips head screw under the sticker, but removing it resulted in no ease-of-disassembly improvement.
Eventually, I replaced my wrist with a hammer, using it in conjunction with the screwdriver as a chisel to pop the two halves apart:
As with the Belkin WeMo Switch, the TP-Link HS100's power and digital subsystems are located in two separate PCBs. Here's the underside of the power PCB:
An easy lift-off exposes the bulk of its AC switching and AC-DC conversion guts. At top and bottom are the two six-terminal female connectors that mate it to the digital PCB below it:
Speaking of which, here's one side of the digital PCB, still ensconced in the enclosure:
And here's a closeup of one of the two six-pin extension bundles that electrically mate the two PCBs, presumably passing both DC power (from the power PCB) and switch control signaling (from the digital PCB):
Removing the digital PCB from the chassis allows us to take a closer look. This side is dominated by the Qualcomm Atheros AR9331 2.4 GHz Wi-Fi SoC. You can also see the PCB-embedded Wi-Fi antenna along the right side:
Flip the PCB over and the memory subsystem comes into view. On the right is a Zentel Electronics A3S56D40GTP 256 Mbit DDR SDRAM. And on the left is a GigaDevice 25Q32CVSIG 32 Mbit serial flash memory (that's a company I can't say that I've ever heard of before!).
Last but not least is a shot of the switches and other plastics underneath the digital PCB. Believe it or not, in spite of my prior "chiseling," the HS100 still worked (albeit with an integrity-compromised enclosure) when I put it back together!