Ramp voltage or current down for 12VDC gear motor w/ Leonardo, relay shield ?

is possible ramp or down 12vdc somehow w/ leonardo , feed through relay shield used h-bridge flip flop [cw/ccw] motor.   i have tried many ways time delay slow motor down it's not working out , i'll burn relays anyways.  mass i'm spinning motor , gear reduction great, motor stops gearbox locks , of force on directional brake it's still harsh plastic , metal...

i need ramp voltage down 12v  5v in 200 millisec or so.

i don't think leonardo capable of doing on own have 4x 2n3055's , few lm317 around unless can think of simpler setup.

process

start motor cw x-time
slow motor xt
stop motor xt
start motor ccw xt
slow motor xt
stop motor xt

loop xt

stop until reset

what curent draw of 12volt motor.
there gate opener project same problem.
forum.arduino.cc/index.php?topic=352403
slowing motor down @ end.
i posted relay/mosfet motor circuit there (#27).
with added current measurement in case motor gets stuck.
speed-up/slow down motor pwm.
look @ "fade" example in ide.
leo..
 

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