|File Size||65.68 KB|
|Create Date||December 24, 2015|
Ultrasonic Movement Detector Circuit Project
Battery operation is not recommended for this ultrasonic movement detector circuit. As the battery potential decreases the sensitivity will change. This is partcuarly so if the unit is triggered often (as in detecting a door opening.) It is better to use a power supply. Use 9V to 12V DC. You could go to a maximum of 15V but you may have to replace the 78L05 by a 7805.
Immediately after you connect the power let the unit stand for at least 20 seconds so whole circuit will settle down electrically. The schematic shows that the setting of the trimpot value is critical to the operation of the detector. We provide a 1M trimpot. Set it to about 400K by eye. We have found that below about 300K the detector is too sensitive and will self-trigger. Trial and error will show the best setting for your particular requirement.