Using this schematic electronic project can be designed a very simple water level indicator electronic circuit that uses a 7-segment display to indicate the water level (low, half and full)in the tank. This water level indicator electronic circuit shows the water level by displaying L, H and F for low, half and full, respectively.
This Lie detector circuit is designed using few common electronic components .The function of this lie detector circuit is based on the variation of the skin resistance that is used to vary the frequency of a tone oscillator . The contact rings can be two bars rings , about ¾ “ .This lie detector circuit can be powered using a 9 volts DC power supply or a battery .
Using the LM1830 fluid level detector device that sense the presence or absence of aqueous solutions can be designed a very simple flow switch circuit electronic project.
Using this flow switch circuit you can implement HIGH and LOW limit control controlling the operation of pumps or solenoid actuated valves .