How to get signal from hall flow sensor FM-HL3012? (STM32F103C8T6 board)

[IUSTI.1]

Hello. I try to get signal by ETR pin my STM32F103C8T6, but get floated count of pulses, much more than wroted in manual.

My video: https://www.youtube.com/watch?v=p-3flyYvOg0

My wiring diagram: https://yadi.sk/i/aH0v7njCSlYeeg

The manual: https://datasheet.lcsc.com/szlcsc/1912111437_EPT-TECH-FM-HL3012_C379915.pdf

Is my diagram wright?

Have you ever worked with such kind of sensors?

PSC is set to 99, and I get 2401 pulse on 200 ml. It's mean that the MCU gets 240100 pulses, but according to the manual it should be 646.

[ANT11]

May I ask if you checked the signal at the sensor output vs. at the BC547 collector?

Is this bipolar transistor correctly biased?