Portable Formaldehyde Detector Indoor

Formaldehyde, chemical formula for an experiment. Is a kind of strong excitantodour of colored gas. Formaldehyde is a gas at room temperature conditions, butusually in the form of aqueous solution. Formaldehyde is a kind of important organicraw materials, mainly used in plastics industry, synthetic fiber, leather industry,medicine and dye, etc. Formaldehyde is protoplasmic poison, can combined withproteins, inhalation of high concentrations of formaldehyde, there will be a severerespiratory stimulation and edema. The skin direct contact with formaldehyde, cancause dermatitis, splash, necrosis, etc. Often in a small amount of formaldehyde, cancause chronic poisoning, pregnant women to long-term could lead to a new babydeformity, even death. Toxic chemicals in our country priority control formaldehyderanked second on the list. Formaldehyde has been the world health organization(WTO) as material cause cancer and birth defects, is regarded as the allergy source, isalso one of high potential mutagenic.Although at present many determination methods of formaldehyde, such asspectroscopic method, chromatography, fluorescence method, chemical method,electrochemical method, etc., most of these methods must use atmospheric samplerfirst on the formaldehyde in air to absorb in the night, then back to the lab for analysis.In this case, the experiment cycle is long, not suitable for rapid detection in publicplaces. And only electrochemical method can fast accurate detection of formaldehyde.This paper introduces a portable formaldehyde detector based on electrochemicalsensor.On the design of hardware circuit, the use of electrochemical sensors, sensorwhen the formaldehyde diffusion to internal, react with internal liquid, produce aweak current signal, current signal is converted to a voltage signal through the workcircuit, voltage signal into a signal processing circuit, the input to the AD ADconverter, in AD sampling to the single-chip microcomputer, signal processing, theninto a button LCD also communicate with the operator.On the software design, as far as possible to shorten the running time of the CPUas the principle to design programs, try to reduce system power consumption. Whennone of the instrument operation after a period of time, the system will automatically shut down part of the peripheral device and MCU in the sleep state in order to reducepower consumption. In the signal processing arithmetic, using median filter, in orderto reduce the disturbance to the system.In debugging and the experiment, after complete the basic function, using theinstrument to test the formaldehyde content in indoor, the basic reflect the distributionof indoor formaldehyde content.