this is water alarm ball,
this is very usefull gadget,
and helping in save water.
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Step 1: What You Need
one bc547 transistor,
3.7 v li ion battery,
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.