Abstract-This paper presents a new architecture for multiuser remote laboratory based on an embedded web server used for experiment with the MCS-51 microcontroller system. The design for the remote lab uses a green computing approach, with the aim of reducing energy consumption, lowering the cost of procurement systems, improving performance and use, and also saving space. The remote lab system uses multi user and multi device architecture to support collaborative work and improve scalability. The design of the remote lab has n modules experiment, and each module can be accessed by a single user or a group which consists of several user. The prototype of a remote lab that has been realized consists of an embedded web server based on Raspberry Pi as the remote lab gateway and 2 experiment modules that are controlled by an embedded web server based on MCS-51 microcontroller. Development of the system is expected to contribute to creating an efficient remote lab that is able to facilitate collaborative work and support green computing.

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We report an experimental of free-space optical communication (FSOC) system that use tube propagation simulator (TPS) as the turbulence medium. The FSOC system use wavelength of 1550 nm at the rate transmission of 1000 Mbps and amplified with EDFA at the output of +23 dBm. Index structure of 10-15-10-13 as the representation of atmosphere index turbulences are used for simulation of intensity distribution model or scintillation. The simulation use gamma-gamma and K model as well. The beam wave propagation models used in simulation are plane wave, spherical wave and Gaussian wave. Spherical wave achieves highest performance via gamma-gamma in strong turbulence. While Gaussian wave achieves highest performance also via K model. We also found, characteristical FSOC system performance is calculated more accurately with gamma-gamma method for strong turbulence than K model. The performances from gamma-gamma for strong turbulence are at 22.55 dB, at 5.33×10-4 , and at 9.41 ×10-6. Abstrak Performansi Sistem Komunikasi Optik Media Atmosfir (Free-Space Optical Communication) dalam Kondisi Turbulensi Kuat. Kami melaporkan eksperimen sistem komunikasi optik media atmosfir (FSOC) menggunakan tube propagation simulator (TPS) sebagai kanal media turbulen. Sistem FSOC menggunakan panjang gelombang 1550 nm pada tingkat transmisi 1000 Mbps dan penguatan sinyal dengan EDFA pada luaran +23 dBm. Struktur indeks atmosfir pada kisaran 10-15-10-13 digunakan sebagai parameter skala turbulensi untuk menghitung distribusi model intensitas atau sintilasi. Simulasi perhitungan menggunakan model statitistik gamma-gamma dan K. Model propagasi gelombang yang digunakan dalam simulasi adalah gelombang datar (plane wave), gelombang sirkular (spherical wave), gelombang Gaussian (Gaussian wave). Gelombang sirkular menghasilkan performansi tertinggi menggunakan model gamma-gamma pada turbulensi kuat. Sedangkan gelombang Gaussian menghasilkan performansi tertinggi menggunakan model K. Kami juga menemukan bahwa karakteristik performansi sistem FSOC dapat terukur lebih akurat menggunakan metode gamma-gamma untuk turbulensi kuat daripada model K. Hal tersebut mengacu pada hasil simulasi dan eksperimen. Hasil tersebut adalah dalam kondisi turbulensi kuat performansi berada pada rentang 22,55 dB, dalam rentang 5,33×10-4 , dan pada rentang 9,41×10-6 .

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