Bogdan Radacanu Tears Open a TP-Link TK50 Smart Bulb, Finds a Surprisingly Low-Power Wi-Fi Module
Purchased more for curiosity than use, the TK50 proved home to a high-efficiency Wi-Fi module — around half the current of an ESP8266.
Engineer Bogdan Raducanu has performed a teardown of the TP-Link TK50, a somewhat unusual LED filament-based "smart" lightbulb with Wi-Fi connectivity — and, it transpires, a Mediatek MT7682 SoC.
"When I saw this KL50 Wi-Fi light bulb on sale, I thought I want to grab one and see what is inside," Raducanu writes. "A quick search revealed no details about the insides of filament Wi-Fi light bulbs. I did not use the light that much, I was more curious of what was inside."
It's clear from Raducanu's imagery that the TK50 wasn't designed for being taken apart by end users: While the metal Edison screw thread section came off with a little persuasion from a screwdriver, retrieving the electronics required the housing to be cut.
Inside, Raducanu found a BP8516 chip — seemingly a customized version of the Bright Power Semiconductor BP8519C non-isolated offline CV converter — along with a Linkage Goston Electronics SM2123E constant-current LED driver.
The heart of the system is a Wi-Fi module powered, Raducanu discovered, by a Mediatek MT7682 SoC When removed from the bulb itself, the module booted up fine and was able to control an LED directly — and drew just 33mA at idle, around half that of Espressif's ESP8266 commonly found in similar smart bulb products.
"The light bulb is quite efficient," Raducanu concludes. "Standby power is comparable to IKEA lights which use much lower power Zigbee radios, but I think the 0.4W is still quite a lot because one day of standby is almost 1.5 hours of full ON. So if you consider the typical 3h per day usage, this light will consume 50% more energy than a dumb one, assuming you keep it always on and control it via remote."
The full teardown is available on Raducanu's website.