Low-Cost 433 MHz Door Sensors Get Open Firmware

It’s an regrettable fact these times that if you see a cheap piece of client electronics, there’s a very good opportunity its only low cost because it is built to lock you into some ecosystem wherever you’ll possibly end up shelling out a membership, or even worse, have your individual info offered powering your again. One of the most effective tools we have versus these kind of anti-shopper practices is the growth of open supply firmware replacements that place handle of the product into the palms of the group, fairly than a corporation.

Now, many thanks to the perform of [Jonathan Armstrong] we have this sort of a firmware for the 433 MHz magnetic door and window sensors that you can choose up on AliExpress for $4 USD a piece. The new firmware not only guarantees you can use these sensors with a vast array of receivers, but adds a quantity of new capabilities about their stock configuration.

In addition to tweaking the transmission protocol so it can be picked up with present open source tasks these kinds of as the well-liked rc_swap library, [Jonathan] has also extra a periodic heartbeat signal that can be employed to verify the sensor is nevertheless on-line. The new firmware will also transmit the standing of the sensor’s inner tamper swap, alerting you to the likelihood that someone is striving to physically manipulate the sensor.

He’s got extra suggestions for capabilities, but tells us he could use some assistance from people seasoned with the 8051 architecture. [Jonathan] says the development applications [Vincent Defert] place alongside one another for the STC15 microcontroller employed in the sensors received him on the proper keep track of, but he’s battling to use emulated EEPROM as code area. If he could determine that out, it would pave the way for additional abilities this sort of as connecting added sensors to the board.

Substitution firmware projects can not only cost-free a machine from the proprietary ecosystem it was intended for, but open up a full new world of prospects. Just one of our most loved examples is the custom made firmware [Aaron Christophel] developed for Xiaomi’s Bluetooth thermometers, which took a cheap vendor-locked gadget and turned it into a smart household powerhouse.