Another example with LM3914 is sound level, water level and voltage level can be used in many applications. Sensor Used for Alcohol level measurement MG-3 The level is observed with 10 LEDs at the LM3914 outputs. Supply voltage dc 12 volt dc.
Simple Alcohol Level Meter
The small circuit will show you the alcohol in your breath and therefore your blood alcohol concentration (BAC).
Driving under the influence of even a small amount of alcohol is certain to suffer. Response times will be longer and although you may feel confident about driving, anything that requires decision-making can have disastrous results.
The Alcohol Level Meter circuit can be used to detect and display the presence of alcohol in your breath. It works with sufficient sensitivity to detect the amount of alcohol in the blood below the critical 0.05% concentration.
Before we go any further, let’s make one thing clear: this unit does not and cannot replace highly calibrated devices used by the Police. Therefore, “0. Below 0” or “0. It should not be used to make a driving decision based on a “below 0” reading. Our advice would be: Don’t drink and drive!
Alcohol Meter Circuit Diagram
MG3 Alcoholmeter Circuit
Source: http://www.siliconchip.com.au/cms/A_105289/article.html
MG3 Alcoholmeter Circuit PCB schematic alternative link:
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Published: 2008/09/03 Tags: analog circuits projects
PIC16F628 LC meter circuit
LC meter circuit made with 16F628 microcontroller can be used to measure the inductor and capacitor values.