Fajar Budiman

2D map creator for robot navigation by utilizing Kinect and rotary encoder

2D map creator for robot navigation is used for robot to move around the surrounding without any collision. Typical robot navigation is relied on ultrasonic sensor as well as rotary encoder. In this paper, we present 2D map creator system for robot navigation based on Kinect device and rotary encoder. 2D map creator system allows robot for self-mapping the surrounding area while robot is moving around. The output is a 2-dimensional (2D) map representing areas that have been passed by the robot. Next, the map is used by robot to return to home automatically. Moreover, we present a technique in map creator system for robot navigation. The Kinect device and rotary encoder are placed on the robot. The depth image is utilized to distinguish between obstacle and non-obstacle object. The combination between depth image and rotary encoder produce a 2D map used for robot navigation. We use Djikstra algorithm for calculating the shortest way between robot positions and home position. Our system has been tested under laboratory environment. The effective distance range is 60 to 600 Cm. Our rotary encoder sensor is also successfully realized and has average error 5.05%. Our 2D map creator required 1.46 second for every creating map at one location. Also, it has 2.23% of error distance on 2D map. All experiment results show that our 2D map creator is ready for performing return to home automatically.

Pengarah Suara Pada Sistem Audio Berdasarkan Beda Phasa

Pemberian informasi seperti pengumuman, ceramah, dan musik sering dilakukan dalam berbagai acara yang memerlukan ruangan yang luas. Supaya pemberian informasi hanya mencapai target yang dituju dan tidak mengganggu pengunjung lain maka suara harus diarahkan untuk lokasi tertentu. Pada penelitian ini telah dilakukan sebuah perancangan dan realisasi sistem deret speaker dimana intensitas sinyal suara dapat diarahkan dengan sudut kemiringan antara -90o sampai 90o. Untuk menghindari munculnya intensitas suara pada arah yang berlawanan maka jarak antar titik pusat speaker untuk frekuensi 2Khz adalah 8,6 centimeter. Pengarahan suara dilakukan dengan cara memberikan waktu tunda di setiap speaker dengan menggunakan Field Programable Gate Array ALTERA DE-2. Sinyal audio dikonversi dengan menggunakan Analog to Digital Converter 24-bit. Waktu tunda tersebut dihasilkan dengan menggunakan sub program 8-bit D flip-flop dengan clock input sebasar 1 mikro detik. Data pengujian dengan menggunakan osiloskop menunjukkan untuk waktu tunda pada beda phasa 90o sampai 90o memiliki rata-rata kesalahan 3,5%. Data hasil pengujian lobe deret speaker menunjukkan rerata kesalahan pengarahan suara sebesar 19%. Sistem dapat diterapkan pada berbagai acara komersil sehingga meningkatkan efisiensi penggunaan daya dan mengurangi noise lingkungan.

Rancang Bangun Wireless Sensor Network Pada Pendeteksi Dini Potensi Kebakaran Lahan Gambut Menggunakan Banana Pi IoT

Lahan gambut merupakan bagian dari ekosistem yang banyak mengandung bahan organik yang tidak mudah terurai. Seringnya terjadi kebakaran lahan gambut membuat Indonesia kerap menderita kabut asap, sehingga diperlukan suatu sistem yang dapat mendeteksi potensi terjadinya kebakaran lahan gambut. Telah banyak penelitian tentang hal penanganan masalah tersebut, namun penelitian yang ditawarkan biasanya berupa pendeteksi paska kebakaran lahan gambut. Selain itu banyak teknologi yang ditawarkan mempunyai harga produksi yang mahal dan penggunaan daya yang tinggi. Sistem yang dirancang pada penelitian ini adalah penerapan Wireless Sensor Network menggunakan topologi tree pada pendeteksi dini potensi kebakaran lahan gambut yang diintegrasikan dengan Internet of Things. Menggunakan Arduino sebagai prosesor dari sensor node yang dibuat dan menggunakan Banana Pi sebagai server dari keseluruhan sitem. Sistem ini mengutamakan penanganan sebelum terjadinya kebakaran dengan membaca suhu lingkungan setiap node. Hasil dari sistem keseluruhan dapat dilihat pada tampilan halaman web yang dapat menampilkan informasi suhu permukaan lahan gambut. Jarak optimum peletakan antar node adalah 100m dan kesuksesan membaca GPS mencapai 80%.

A handy and accurate device to measure smallest diameter of log to reduce measurement errors

Log is a forest product as a basic ingredient of furniture such as cabinets, chairs, and other refined products. It is widely used by all people as households, offices, and shops. Thus, business in log industry is promising. Yet, a problem in pricing of log is faced by log business industry. Traditional pricing method is generally based on the calculation of log content (volume) where the value begins with the diameter measurement. Workers measure the smallest diameter value of log to be used as a reference. Conventionally, calculation begins with adding the horizontal and vertical diameters; the result is then divided by two. Error in measuring a log diameter occurs since it does not always form a perfect circle. Besides, measurements taken by one person to another will vary. In fact, a small difference of just one centimeter can determine the log grade which impacts on the price and economic loss of the industry. In this paper, a handy but accurate device is proposed that can be used in standardizing the measurement of log. The device is designed with raspberry pi as single board circuit embedded with image processing technology. The device is equipped with SD card to be easily replicable for mass production, and it has only 500 gram weight and dimensions of 90 × 55 × 60 mm. The measurement tests of real log with grade 17, 18, and 19 result 0.4%–1.9% and 0.08%–3.4% for minimal and maximal errors respectively. The proposed tool exhibits its accuracy, and it also effectively reduce the time measurement twice compared to conventional way.

Non-Dispersive Infrared (NDIR) sensor design and its application on alcohol detection

Alcohol concentration measurement becomes very important in mixing a chemical solution. The measurement in general uses a conventional method that requires direct contact and a long time of measurement period, such as using a capacitive sensor. Another method is Non-Dispersive Infrared (NDIR) which is capable of measuring the concentration of alcohol without any direct contact and within relatively short test period. In NDIR system, infrared light generated by an infrared source passes through the sample tube. Then, the infrared light that can be absorbed by the hydrocarbon particles of the alcohol is sensed by an infrared detector. In this paper, the infrared source is made of inexpensive 19 Gauge nichrome wire heated at different temperatures to find the best alcohol absorption. PID controller system is employed to maintain constant temperature of the infrared source. The infrared light absorbed is then detected by a thermopile sensor. The result showed that the best alcohol absorption is at 60 °C, and it is proportional to the magnitude of the concentration, the greater the concentration, the higher the value of its absorbance. Absorbance value for distilled water is 0 while the absorbance value for 20% alcohol is at 0.15 and for 60% alcohol is 0.26. This proves that the higher the concentration of alcohol, the infrared light absorbed will be higher. Overall, the inexpensive NDIR system is capable of observing and detecting alcohol that may be used for other solutions in further research.