LowCost Spectrum Analyzer

Posted on Feb 5, 2014

This circuit uses a very simple approach to detecting smoke in the air. Quite simply, it uses a bulb as a light source, and an LDR (Light Dependent Resistor) as a light detector. As fire smoke comes between the bulb and LDR, the resistance of the LDR changes, which in turn trigger an alarm. This probably isn`t an ideal approach given that ambient

LowCost Spectrum Analyzer
Click here to download the full size of the above Circuit.

light levels are likely to cause false alarms, however it is an interesting experiment. Just please don`t set any fires while experimenting. And please don`t rely on it as a replacement for a real fire alarm device.

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