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: Rotary Encoder Series Testing by Using Hall Effect Sensor to Measure Water Level Change.
Abstrak: Tinggi muka air merupakan salah satu parameter hidrologi. Tinggi muka air dapat menggambarkan karakteristik suatu daerah aliran sungai. Perubahan tinggi muka air dapat diukur dengan menggunakan alat ukur tinggi muka air tipe pelampung. Cara kerja dari alat tipe ini adalah dengan mengukur arah dan besar perubahan berdasarkan pergerakan pulley yang berputar karena adanya perubahan tinggi muka air. Pada alat tersebut umumnya terdapat sensor gerakan dan rangkaian penerjemah arah gerakan. Rangkaian penerjemah gerakan dapat dibentuk dari IC (integrated circuit) seri 4093. Dengan menggunakan hall effect latch sensor sebagai sensor gerakan yang memberikan input bagi rangkaian penerjemah arah gerakan, perubahan tinggi muka air dapat diketahui. Untuk dapat mengetahui besar perubahan tinggi muka air perlu dilakukan pengolahan terhadap sinyal output dari rangkaian penerjemah arah gerakan. Pengolahan sinyal tersebut dilakukan dengan menambahkan rangkaian inverter serta rangkaian monostable positive - negative edge trigger dengan output terakhir pada sirkuit dengan gerbang OR. Pada penelitian ini, untuk setengah putaran pada pulley dihasilkan satu sinyal yang menandakan gerakan naik ataupun turun. Besar gerakan tersebut dipengaruhi oleh ukuran pulley, Dengan menggunakan pulley bediameter 1cm didapatkan resolusi sebesar 1.57cm.
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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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