If you wish to add humidity and temperature sensors to your private home automation sensor, you may — like [Maker’s Fun Duck] did — purchase some generic ones for a couple of buck. For a greenback, you get a little bit sq. LCD with sensors and a button. You even get the battery. Are you able to reprogram the firmware to bend it to your will? As [Duck] exhibits within the video beneath, you may.
The system advertises some customized BLE companies, however [Duck] didn’t wish to use the seller’s telephone app, so he cracked the case open. Inside was a microcontroller with Bluetooth, an LCD driver, a sensor IC, and little or no else.
The processor is an ARM Cortex M0, a PHY6222 with very low energy consumption. The LCD is a really low cost panel with no drivers onboard. All of the drive electronics are on the PCB. The sensor is a CHT8305C which makes use of I2C.
Fortunately, the PHY6222 has a publically accessible SDK with English documentation. The PCB has two units of UART pads and it’s attainable to flash the chip through one of many UARTs.
Finally, [Duck] put a customized firmware on the field, however we had been intrigued by the concept for a buck you could possibly get a little bit low-power ARM module with an LCD and a sensor. It looks as if you could possibly do extra with this, though we’re certain the LCD is just not very normal goal, absolutely this little field may act as a panel meter, a countdown timer, or plenty of different issues with some customized firmware.
These are, after all, knock offs of the marginally dearer Xiaomi sensors, and people are flashable, too. We aren’t certain how correct both sensor is, however humidity measurement is a posh matter.
