How to read output across a 2-wire DC magnetic or hall effect sensor? Also my requirement of switching frequency is 1000 Hz, but most of the sensors out there have a maximum switching frequency of 5000 hertz. Will this affect accuracy when I measure low frequencies?
If the Hall sensor can be triggered as fast as 5kHz then operating it at 1kHz shouldn't really be a problem. Hall sensors work all the way don't to DC and are designed to have a flat frequency response. I'm supposing that the Hall sensor you have considered has a digital output from the way you've couched the question. You need to read its specification to see what supply voltage it needs and what pulsing output voltage it produces. Then you need to ask yourself what it feeds into (your circuit) and if the signal levels are compatible then there should be no problem.
If you want more detail in the answer you have to give more information in your question.