Judul: Rancang Bangun Pendeteksi Otomatis Ketinggian Permukaan Air Berbasis Sensor Medan Magnet UGN3503
Abstrak: An automatic detector of water level with sensor UGN3505 as detector of changes water level has been successfully be made for this research. Sensor UGN3505 is a hall effect sensor which works based on the large magnetic fields on the surface. The output voltage generated by the sensor without the influence of a magnetic field is 2,525 volts, the output voltage is different than it should be 0.025 volts is 2.50. This shows that the sensor is not completely free from magnetic field sources, there is still the effect of the Earth's magnetic field to the sensor. Sensor output voltage will increase, with increasing magnetic field on the surface of the sensor. As the central data processing equipment, used microcontroller ATmega16. The input of microcontroller is the changes output voltage of sensor than has been converted into digital data (internal ADC ATmega16) caused the changes of magnetic field. The digital data are readable by microcontroller be processed and displayed in the 16x2 LCD, LED indicator and buzzer. Programs created using software tools CVAVR with C + + language.
Keyword: Sensor UGN3505, magnetic field, hall effect, CVAVR, ATMega16, DC

Judul: Rancang Bangun Alat Pengukur Intensitas Hujan Dengan Metode Jungkat-Jungkit Berbasis Sensor Medan Magnet UGN3503.
Abstrak: This research has been done on making rain intensity gauge using a magnetic field sensor UGN3503. Sensor UGN3503 can detect the magnetic field on its surface. The sensor is placed above a seesaw that was inserted magnet. The magnet used is Neodymium magnet is a type of permanent magnet with stongest magnetic field compared to other types of fixed magnetic field magnets. When the seesaw discards rainwater, the distance between sensor and magnet is closer and causing the keluaran voltage of the sensor increases. The keluaran voltage of the sensor is compared with a reference voltage by the comparator so that the sensor keluaran data is in digital form and ready to be processed. As the processing and sending of data used ATmega16 microcontroller, microcontroller take sensor data once every 100 ms and display data to the LCD (Liquid Crystal Display) 16x2. Every 30 minutes the data is processed into the rain intensity is then stored into a computer.
Keyword: rain intensity, seesaw, comparator, microcontroller, sensor UGN3503.

Judul: Lejeuneaceae Subfamily Ptychanthoideae (Hepaticae) in  West Java
Abstrak: Subfamily Ptychanthoideae of the family Lejeuneaceae (Hepaticae) in West Java is still poorly known. Publications on this subfamily are out of dated and written in the 19th or early of 20th century. The last taxonomic treatment of Ptychanthoideae of West Java was in 1933, many species names have changed since then. Studies on Ptychanthoideae of West Java are urgently needed. Studies on the Ptychanthoideae were based on the specimens collected from West Java. A total number of 361 of specimens deposited in the Herbarium Bogoriense (BO), Herbarium Biotrop (BIOT), Gottingen Herbarium (GOET) and Bangi Herbarium (UKMB) were examined, those are old and several recent specimens collected in West Java. Recent collections were made from Telaga Warna, Ciater, Gunung Halimun Salak National Park, Cibodas Botanical Garden, Bodogol Education Center and Conservation (Gunung Gede Pangrango National Park), University of Indonesia Campus Depok, including several collections from Banten Province. Twenty four species of Lejeuneaceae subfamily Ptychanthoideae are known from West Java, belonging to 8 genera namely Acrolejeunea (Spruce) Schiffn. (2 species), Archilejeunea (Spruce) Schiffn. (1 species), Lopholejeunea (Spruce) Schiffn. (10 species), Mastigolejeunea (Spruce) Schiffn. (3 species), Ptychanthus Nees (1 species), Schiffneriolejeunea Verd. (1 species), Spruceanthus Verd. (2 species) and Thysananthus Lindenb. (4 species). Two new records of Ptychanthoideae: Mastigolejeunea indica Steph. and Thysananthus minor Verdoorn are reported for Java. A determination key to the species is presented including their descriptions and illustrations.
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