This paper presents the design and construction of an ultrasonic scaler. The principal of Phase-Locked Loop circuit inside the IC 4046B controls the 25-kHz frequency generator with constant phase and frequency.The coil inside the hand-piece sheath produces the magnetostriction process with the magnetostrictive stack which works only at 25-kHz frequency. This proces causes the magentostrictive stack to expand and contract with high frequencies making the scaler tip to vibrate more than 20000 times per second. This dental scaler could be used to eliminate the micro-organisms in the form of plaque or tartar and dirt in the gum groove and around the tooth root surface. This tool is as effective as and cheaper than the imported equipment used by dentists. In addition the construction of an ultrasonic dental scaler helps the staff to improve their maintaining skills.

This research is Design and construction board led dot matrix was create for study about microcontroller. It apply to use in communication & information indoor type by sending messages from computer on internet network systems. This research has implemented LED dot matrix display for display message characters. The research is composed of 4 major parts: the first part is LED dot matrix display with dimension of 16x192 dots. The second part is the control circuit by using a micro-controller ARM 7 which receives the data from computer the third part by using Microsoft Visual Basic. the forth pat program remote desktop. From tests and results we have found that it can display the message characters which move from Internet System successful.