This project allows almost every door to be opened via low-power Bluetooth, while the battery has been idle for several years.
    I want to open the door by fingerprint, so I need some door-opening devices.
    Specifically, I want to open the door by pulling the handle.
    In addition, cables are unacceptable. Therefore, some low-power communication methods and hardware are needed.
    For this reason, BLEnky is the best tool as it allows the low-power consumption feature of the nRF52 to be utilized without writing any C code.

    In fact, the only code needed is this gpioASM fragment:

    Therefore, write 100 and 110 to the output, enable the driver and step 540 times.
    Write 000 disables the driver.
    In order to make with BLEnky nrf51 run the code, I only need through my ESP MQTT to send 00800001 bytes c1200101c52001b0029c0401c0 to BLE gateway.
    Twelve AA batteries provide sufficient power to drive the stepper motor.