Water Alarm Ball

About: this is amezing app

this is water alarm ball,

this is very usefull gadget,

and helping in save water.

Step 1: What You Need

you need

one bc547 transistor,


3.7 v li ion battery,

piezo buzzer,


one plastic ball.

Step 2: Build Circuit

build circuit as circuit diagram with PCB&soldering iron

Step 3: Fitting All Component

fitting all component in ball,

first cut the ball with cutter,

and fix circuit in ball and out side two wire

and joint the ball.

for full voice some do hole in ball opposite site of two wire.

Step 4: Use

where do hole in ball fix rope with small hangar,

and hang over the water container,

when water rise up to ball two terminal and touch water,

the buzzer is activate.



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    3 Discussions


    1 year ago

    Are you sure of your schematic diagram? Seem you are trying to bias the NPN transistor with a ground. Usually this type circuit uses the positive lead from the battery to bias the base when current flows through the water probes. Just wondering.

    2 replies

    Reply 1 year ago

    Is the battery turned around?