Abstract: An obstruction sensing and control arrangement for door or gate opening-closing mechanisms. The arrangement compares the operating rate of change of a predetermined characteristic with a preset rate of change and stops or reverses the motor in the opening/closing mechanism. The characteristic preferred is motor body temperature which is monitored indirectly. The control arrangement also includes a back up static control threshold to sense a second static operating characteristic of the motor and a second comparator means set at a preset threshold level to stop or reverse the motor. A common motor sensor is used for both the dynamic and static control thresholds. The invention also includes means to sense operating temperature and to alter the preset static threshold level automatically in response to temperature changes.