Drive dual coil steppers without H Bridge

hey,

i came across dual coil stepper based instruments out of car want use display stuff on arduino. coil impedance 200 ohms. can't afford h bridge or motor drive shield, though they're 5 bucks. (don't ask.)

i want other ways drive these small instruments. if understood right make pointer move have drive coils in reverse polarity, 1 powered + / - , other - / + , reverse make go other way. assumption correct? driving both @ same time should take 5 volts / 100 ohms = 0.05amps.

so yeah, i'm pretty looking easy makeshift way make use of gauges. got loglevel mosfets (irl540n, know, overkill, might work) lying around suitable. yeah can't wrap head around yet, advice great.

thanks

sooner or later i'll drive shield it's improvising , learning time.

by way, if pwm output pin 0/off, pulled gnd? , if not, if used resistor pull gnd maybe reverse polarity thing somehow?

5v , 200ohms per winding(*) _is_ within capabilities of arduino pins drive - you
will need protection diodes bolster on-chip ones (preferrably schottky diodes).

so bipolar motor need 4 pins, each protection diode ground , vcc, and
then question of software.  in effect each pair of pins h-bridge.

(*)  5v / 200 = 25ma, whereas pin absolute maximum 40ma.  lose voltage,
perhaps you'll 4v drive between 2 pins due losses in output
transistors.

Arduino Forum > Using Arduino > Motors, Mechanics, and Power (Moderator: fabioc84) > Drive dual coil steppers without H Bridge

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