Judul: Rancang Bangun Pendeteksi Umur Panen Spirulina platensis Berdasarkan Optical Density (OD).
Abstrak: Efisiensi waktu dalam penanaman Spirulina platensis merupakan hal yang sangat menguntungkan. Pembuatan alat pendeteksi umur panen menggunakan sensor TCS230 ini dapat membantu petani dalam memprediksi umur panen Spirulina platensis dengan lebih mudah dibandingkan dengan cara konvensional menggunakan spektrofotometer. Pantulan warna hijau kebiruan dari kultur Spirulina platensis dideteksi oleh sensor TCS230 yang telah terintegrasi dengan Arduino UNO R3. Tempat pengukuran sampel berbentuk tabung yang terbagi menjadi dua bagian, yaitu tempat sampel dan tempat densor. Hasil pengukuran sensor terhadap sampel Spirulina platensis pada filter biru menunjukkan sensitivitas yang tinggi, lalu diolah sehingga didapatkan hasil berupa nilai Optical Density (OD) dan prediksi fase penanaman dengan R2 sebesar 0.995. Hasil pengukuran tersebut lalu ditampilkan pada LCD 20X4.
Keyword: arduino, optical density, Spirulina platensis, TCS230

Judul: Real-time And In Situ Internet of Things Integrated Microalgae  Growth Monitoring System Based On Optical Sensor
Abstrak: Pemantauan pertumbuhan mikroalga yang dilakukan saat ini masih menggunakan metode yang kurang praktis, yaitu melihat warna kultur atau pengukuran kepadatan sel menggunakan spektrofotometer secara manual. Pembuatan sistem pemantauan pertumbuhan mikroalga terintegrasi Internet of Things ini dapat membantu pengguna untuk memantau pertumbuhan mikroalga dengan lebih tepat dan cepat. Absorbansi (kepadatan sel) dapat diukur untuk kemudian diolah menjadi informasi pertumbuhan mikroalga dengan memanfaatkan fenomena gelombang evanescent yang terjadi pada serat optik,. Pada penelitian ini, Spirulina plantesis dipilih sebagai objek penelitian karena waktu pertumbuhan yang relatif singkat. Hasil pengambilan data sinyal sensor untuk dibandingkan dengan data acuan dengan menggunakan spektrofotometer sehingga menghasilkan persamaan yang dapat digunakan untuk merancang alat untuk mengukur absorbansi kultur mikroalga S. plantesis. Hasil uji coba menghasilkan nilai R-squared sebesar 0.878. Selain diukur dan disimpan pada penyimpanan lokal, data pengukuran juga dikirimkan ke server untuk diolah menjadi informasi yang ditampilkan pada antarmuka web dashboard., Microalgae growth monitoring currently carried out still use methods that have low accuracy and efficiency such as looking at the color of culture or measure cell density using a spectrophotometer manually. The creation of an Internet of Things integrated microalgae growth monitoring system can help farmers to monitor microalgae growth more precisely and quickly. By utilizing the phenomenon of evanescent waves that occur in optical fibers, absorbance (cell density) can be measured and then processed into microalgae growth information. In this study, Spirulina plantesis was chosen as the research object because of the relatively fast growth time. The results of the sensor signal retrieval to be compared with reference data using a spectrophotometer to produce an equation that can be used as a tool to measure the absorbance of S. plantesis microalgae culture. The trial results produce a R-squared value of 0.878. In addition to being measured and stored in local storage, measurement data is also sent to the server to be processed into information that is displayed on the web dashboard interface.
Keyword: absorbansi, evanescent, Internet of Things, mikroalga

Judul: Distribution and Diversity of Ectoparasite Mites on Geckos in Indonesia
Abstrak: Data on the diversity and dispersal of parasitic mites on house geckos in Indonesia are very scarce. In this work, the distribution and diversity of mites living on three species of house geckos, namely Cosymbotus platyurus, Hemidactylus frenatus, and H. garnotii collected throughout Indonesia, has been elaborated. Geckos and mites were captured and immediately preserved in 70% ethanol. Whole mount of the mites was prepared by clearing in lactophenol followed by mounting on polyvinyl lactophenol solutions. The SEM preparation was conducted to examine the detail morphological characters of the mites. The results showed that among 448 individuals of geckos, 221 geckos were infected by Geckobia mites. Prevalences of C. platyurus, H. frenatus, and H. garnotii infested by mites were 14.8%, 50.69%, and 79.6%, respectively. Three different spesies of Geckobia (G1, G2, and G3) could be differentiated; and based on similarities of their morphological characters to ones described in published literatures, Geckobia G2 is Geckobia glebosum and Geckobia G3 is Geckobia bataviensis while G1 could not be identified to the species level. The highest mean intensity of Geckobia G1 infestation was found on H. garnotii (I=7.0), G. glebosum infestation on H. frenatus (I=3.5), and G. bataviensis infestation on H. garnotii (I=11.8). In general, C. platyurus was infested by the least number of mites. Geckobia G1 were found living on the skin folds on the claws, G. glebosum were found mainly on the body and thigh, and G. bataviensis were found on almost all parts of the host’s body. Geckobia mites are distributed randomly throughout Indonesian Archipelago, following the pattern of distribution of their hosts. So it is concluded that Geckobia G1, G. glebosum, and G. bataviensis are sympatric.
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