Judul: Rancang Bangun Komunikasi Data Wireless Mikrokontroler Menggunakan Modul XBee ZigBee (IEEE 802.15.4)
Abstrak: This research implement microcontroller wireless data communication on automatic irrigation. Microcontroller unit (MCU) is used to read soil moisture level by using Soil Moisture sensor. Sensor values need to be sent to main controller (server computer) for monitoring. Past research (Nugroho 2011) has implemented serial cable for communication between field controller and main controller, but it will be inefficient for field application because serial cable implementation would be difficult if the field is far from the computer. Therefore, wireless data communication needed. XBee was choosen because compared to other wireless devices (Bluetooth, GSM, and WiFi), XBee has the lowest power consumption, lowest cost and the most suitable for monitoring and controlling. XBee performance is tested using the number of data packet loss. From the test result, the best distance to place the field controller is obtained, which is less than 20 meters from the main controller. For a better performance in decreasing the data packet loss incurred by the longer distance, it is advised to use the newer XBee series.
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Judul: Rancangan dan Uji Coba Otomatisasi Irigasi Kendi.
Abstrak: Development of science and technology today make automatic control have important role. It gives us ease to get performance in dynamic system. Automatic control be able to less routine work that operator always do. Automatic control tools have many kinds. Microcontroller ATMega328P is a kind of automatic control. The function is control and record data then save it. Automatic pitcher irrigation system constructions consist on hardware and software. Hardware consist on water level sensor and soil moisture sensor series, microcontroller, stackable SD card shield, real time clock, relay, battery and solenoid valve. Software is a program for microcontroller that used C/C++ language. Each sensor will be calibrated before use. Daily high water level and soil moisture data was data obtained. The data was obtained each 5 minutes. Data in microcontroller was obtained by record data on memory that was set in microcontroller. Calibration results express that microcontroller capability in monitoring high water level and soil moisture has high accuracy. Determination Coefficient calibration equation from the sensor is 0.955 for high water level sensor and 0.887 for soil moisture sensor. Furthermore, set point for control high water level is 5 cm for bottom margin and 14 cm for top margin.
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Judul: Perbaikan Proses Pemurnian Gliserol Hasil Samping Industri Biodiesel Menggunakan Distilasi Vakum
Abstrak: Gliserol dari hasil samping industri biodiesel minyak sawit setiap tahun jumlahnya kian meningkat. Gliserol tersebut umumnya hanya memiliki kadar gliserol 40-50% karena masih banyak mengandung pengotor berupa sisa metanol, sisa katalis, asam lemak, air, maupun bahan pengotor lainnya sehingga perlu ditingkatkan kemurniannya agar dapat digunakan di berbagai industri dan meningkatkan nilai jualnya. Salah satu cara yang digunakan untuk memurnikannya adalah dengan penambahan asam fosfat yang dapat meningkatkan kadar gliserol dari 47% menjadi 83%. Penelitian ini bertujuan untuk mendapatkan kondisi proses pemurnian gliserol (±80%) menggunakan metode distilasi vakum untuk menghasilkan gliserol dengan kadar lebih tinggi (±90%). Kondisi terbaik proses pemurnian gliserol melalui metode distilasi vakum adalah pada suhu 90-95°C dan tekanan 15 InHg (0,51 Bar) dengan kecepatan pengadukan 300 rpm selama 2 jam. Kondisi tersebut menghasilkan gliserol dengan kadar gliserol 94,19%, kadar air 0,01%, kadar abu 2,96%, kadar MONG 2,84%, densitas 1,261 gr/cm3, specific gravity 1,264, viskositas 214 cP, viskositas kinematis (40°C) 106 cSt, warna kuning kecoklatan, pH 6,2, bilangan asam 3,88 mg KOH/g sampel, titik didih 110°C, titik nyala >140°C, titik tuang -30°C, dan titik awan -21°C. Hasil ini menunjukkan bahwa suhu yang digunakan pada proses distilasi vakum telah memberikan pengaruh yang signifikan terhadap karakteristik gliserol murni yang dihasilkan.
Keyword: gliserol, biodiesel, minyak sawit