does anyone know why when i put a voltmeter probes on the gnd pin and potentiometer the realding goes from few milivolts(the reading i get when the electrodes are in the air) to a complete zero?
while im testing that i have everything connected as it should be, however every voltmeter i try show the same things. (I'have tried it with like 3 or four different multimeters, even tried with AC voltmeter:D).
at first i tHought that the drivers were somehow damaged , but it was unlikly because the motors were turning. and then i tried using an oscilloscope and only then i got a reading.
(i have already adjusted my potenciometers, im just curious why doesnt it work with a vltmeter)
oh and if anyone knows a correct Vref equassion that actually is accurate, i COuld realy use one, because I have only seen two, one in howtomechatrinox.com which is way off, and one that i allways get whenever i look for a different datasheet on a4988 (I rated =V ref/(8 * R sense). which also did not work, my motors started to shiver only after i set the current twice as high as the equassion said
With the probes in the air you have an antenna picking up mains frequency from things nearby and
from you (select AC and this will be more obvious), due to the high input impedance of the meter
(probably 10M or more)
Once you connect the probes you don't have an antenna (well, technically you have a magnetic
loop antenna still, but that's way less efficient).