known motion sensor can be used however the preferred sensor switch 21 has the unique feature that one of the contacts of the sensor is a conductive plate 24 having two openings 25 the diameter and spacing of which controls the sensitivity of the switch and the other contacts are in the form of members 26 extending through the openings the use of a stamped and formed plate 24 provides the least expensive contact possible and since the switch is used as a trigger the plate can simply be allowed to slide around on the circuit board so long as the plate 24 is not allowed to slide off the contact members 26 which can easily be accomplished simply by bending over the ends of the two contact members 26 to loosely retain plate 24 in place the use of a plate having two openings fitted over two stationary contact members to move relative thereto without falling off replaces the spring or vibrator of the conventional motion sensitive switch which has a cost of around us 0 10 per sensor mainly due to the cost of the spring or vibrator and the difficulty in properly positioning the moving element relative to the stationary contact or contacts and affixing the element in place no such difficulties exist for the present invention by utilizing a plate with two holes fitted over two stationary contacts the cost of the sensor can be reduced by as much as 90 furthermore since virtually all of the control functions can.