Sensors to measure wrist bending I'm working on gesture gloves project, which means it detect hand movement or current position, to be used in something else such as controlling a car.

I wanted to measure how much the wrist joint is bending, i used flex sensor, but when the wrist is bending while the fingers are pointing to upward ( _| ) the flex sensor became more longer in length than the wrist.. which make it hard for sewing ..

is there any alternative sensor?
It sounds like you have not allowed the flex sensor to slide through a sheath attached to the back of the hand.  Consider attaching a sheath to the back of the glove the width of the flex sensor.  It's length should be equal to or greater than the flex sensor when the glove is worn and the hand is fully dorsiflexed.  Anchor only the wired end of the flex sensor to the glove.  If there is still not enough room for the sensor when the hand is fully dorsiflexed, revers the sensor position and anchor the wired end to the back of he hand.  Allow the sensor to travel beyond the cuff of the glove if necessary.