Broadlink Smart Bulb, a Conversion to Open Source

Smart devices of all sorts are becoming more and more common in everyday households. One such device, smart LED light bulbs, come in a variety of sizes, functionalities, and manufacturers, but all require a WiFi connection and are set up using your smartphone and one of many apps. Gadgets that function in this way pose a variety of issues. The apps that come with them are closed source and require you to provide sensitive data such as the name of your WiFi network, password, and location. They also require a constant internet connection to operate, and control happens through some servers over which the user has no control or authority.

Viktor Takacs has developed and outlined a method to convert these Broadlink smart bulbs to open source. Many of the current bulbs no the market are based on the same ESP8266, so it is quite easy to replace the firmware in them. For bulbs with chips that are not open source nor well-documented, like one with a Broadlink BL3336T-P WiFi module, writing new firmware would first require figuring out what the chip does and how. Instead, it is possible to replace the WiFi chip along with its PCB and other parts that drive the LEDs and design a new, drop-in replacement based on the ESP8266.

This process involves identifying the connections in the circuit used in your particular bulb and reproducing the functionality with ESP8266-based circuit. In the case of the bulb that was reworked in this particular DIY project, the driver panel that housed the Broadlink WiFi controller was a completely separate plugin to the rest of the bulb, making it easy to replace. After designing the replacement circuit and confirming its functionality, it is necessary to create a PCB that fits the size constraints imposed by the bulb design and solder it to the original header.

With the redesigned smart bulb, it is possible to switch the light on and off without the internet, and without trusting information to a third-party app. Settings or features can be changed using the bulb’s built-in web pages, or it can be hooked up to any home automation system. A little DIY should leave you with a smart device that functions exactly as you want.