ALAT PENDETEKSI DINI KEBOCORAN GAS ELPIJI MENGGUNAKAN SENSOR GAS MQ-6

Pembuatan alat pendeteksi dini kebocoran gas menggunakan sensor gas MQ-6 bertujuan untuk mencegah kebakaran karena terjadinya kebocoran gas elpiji yang dapat menimbulkan kerugian. Dengan adanya alat ini maka seseorang dapat mengetahui apabila terjadi kebocoran gas elpiji. Metode yang digunakan untuk membuat alat pendeteksi kebocoran gas elpiji ini adalah metode rancang bangun yang terdiri dari beberapa tahap yaitu, (1) Identifikasi Kebutuhan, (2) Analisis Kebutuhan, (3) Perancangan Sistem, (4) pembuatan, (5) Pengujian Alat, (6) Pembahasan. Alat ini terdiri beberapa bagian, terdiri dari rangkaian catu daya yang menghasilkan tegangan 5 Volt dan -5 Volt, rangkaian sensor MQ-6 sebagai pendeteksi gas elpiji, rangakaian komparator untuk pembanding tegangan dari sensor dan tegangan referensi, rangkaian driver relay dan buzzer sebagai indikator apabila terjadi kebocoran gas elpiji. Alat pendeteksi dini kebocoran gas elpiji menggunakan sensor gas MQ-6 telah berhasil dibuat sesuai rancangan. Berdasarkan pengujian alat, ketika sensor MQ-6 tidak mendeteksi adanya gas elpiji tegangan keluaran sensor ± 1 Volt. Tegangan ini lebih kecil dari tegangan referensi komparator, karena itu tegangan keluaran komparator belum dapat mengaktifkan transistor yang mengakibatkan relay dan buzzer belum aktif. Terdeteksinya gas elpiji oleh sensor MQ-6 menyebabkan tegangan keluaran sensor menjadi ± 3,69Volt. Tegangan keluaran ini lebih besar daripada tegangan referensi komparator, karena itu tegangan keluaran komparator dapat mengaktifkan transistor yang menyebabkan relay dan buzzer aktif. Hal ini menunjukkan bahwa alat pendeteksi dini kebocoran gas elpiji menggunakan sensor MQ-6 bekerja sesuai dengan yang diharapkan

Using context to make gas classifiers robust to sensor drift

The interaction of a gas particle with a metal-oxide based gas sensor changes the sensor irreversibly. The compounded changes, referred to as sensor drift, are unstable, but adaptive algorithms can sustain the accuracy of odor sensor systems. This paper shows how such a system can be defined without additional data acquisition by transfering knowledge from one time window to a subsequent one after drift has occurred. A context-based neural network model is used to form a latent representation of sensor state, thus making it possible to generalize across a sequence of states. When tested on samples from unseen subsequent time windows, the approach performed better than drift-naive and ensemble methods on a gas sensor array drift dataset. By reducing the effect that sensor drift has on classification accuracy, context-based models may be used to extend the effective lifetime of gas identification systems in practical settings

Fluidic hydrogen detector production prototype development

A hydrogen gas sensor that can replace catalytic combustion sensors used to detect leaks in the liquid hydrogen transfer systems at Kennedy Space Center was developed. A fluidic sensor concept, based on the principle that the frequency of a fluidic oscillator is proportional to the square root of the molecular weight of its operating fluid, was utilized. To minimize sensitivity to pressure and temperature fluctuations, and to make the sensor specific for hydrogen, two oscillators are used. One oscillator operates on sample gas containing hydrogen, while the other operates on sample gas with the hydrogen converted to steam. The conversion is accomplished with a small catalytic converter. The frequency difference is taken, and the hydrogen concentration computed with a simple digital processing circuit. The output from the sensor is an analog signal proportional to hydrogen content. The sensor is shown to be accurate and insensitive to severe environmental disturbances. It is also specific for hydrogen, even with large helium concentrations in the sample gas

1700 deg C optical temperature sensor

A new gas temperature sensor was developed that shows promise of sufficient ruggedness to be useful as a gas turbine temperature sensor. The sensor is in the form of a single-crystal aluminum oxide ceramic, ground to a cone shape and given an emissive coating. A lens and an optical fiber conduct the thermally emitted light to a remote and near-infrared photodetector assembly. Being optically coupled and passive, the sensor is highly immune to all types of electrical interference. Candidate sensors were analyzed for optical sensor performance, heat transfer characteristics, stress from gas loading. This led to the selection of the conical shape as the most promising for the gas turbine environment. One uncoated and two coated sensing elements were prepared for testing. Testing was conducted to an indicated 1750 C in a propane-air flame. Comparison with the referee optical pyrometer shows an accuracy of + or - 25 C at 1700 C for this initial development. One hundred cycles from room temperature to 1700 C left the sapphire cone intact, but some loss of the platinum, 6% rhodium coating was observed. Several areas for improving the overall performance and durability are identified

Gas leak detector is simple and inexpensive

Pressure sensor monitors small gas leaks in piping and pressure vessels. A combination of a paper ribbon and adhesive plastic tape is used to cover the area to be monitored and the pressure sensor is placed over a hole in the tape and paper

Modified POF Sensor for Gaseous Hydrogen Fluoride Monitoring in the Presence of Ionizing Radiations

This paper describes the development of a sensor designed to detect low concentrations of hydrogen fluoride (HF) in gas mixtures. The sensor employs a plastic optical fiber (POF) covered with a thin layer of glass- like material. HF attacks the glass and alters the fiber transmission capability so that the detection simply requires a LED and a photodiode. The coated POF is obtained by means of low-pressure plasma-enhanced chemical vapor deposition that allows the glass-like film to be deposited at low temperature without damaging the fiber core. The developed sensor will be installed in the recirculation gas system of the resistive plate chamber muon detector of the Compact Muon Solenoid experiment at the Large Hadron Collider accelerator of the European Organization for Nuclear Research (CERN

Highly sensitive micro coriolis mass flow sensor

We have realized a micromachined micro Coriolis mass flow sensor consisting of a silicon nitride resonant tube of 40 ?m diameter and 1.2 μm wall thickness. Actuation of the sensor in resonance mode is achieved by Lorentz forces. First measurements with both gas and liquid flow have demonstrated a resolution in the order of 10 milligram per hour. The sensor can simultaneously be used as a density sensor