equipment of a digital automatic level control
of water, with the RG-1045S sensor
and Bolt 18F2550 system.
Project development: Moisés Meléndez Reyes
Demo Video in HD:
In this project, for teaching purposes,
a simple model of an on-off
automatic control filling a water container was
built, using the Bolt 18F2550 system and
digital level sensor RG-1045S.
The system can emulate the process repeatedly, and for this purpose includes a
storage container (see Figure 1), which
can be filled again and again through a mini water pump.
It is a control system with1 input and 1
output, ie, the microcontroller Bolt receives a
digital signal in input RC1 and,
through its relay, activate the mini water pump.
In figure 4 the simplified block diagram is shown.
The basic operation of the automatic control is as follows:
if a low water level is detected in the
container (in which case the level sensor will
close its switch), the microcontroller activates the filling
The water level will rise until the level
sensor switch opens, event that will be
detected by the microcontroller, and the
pump shuts off.
The level sensor has a hysteresis range, such that the water level starts
to decline until the switch is closed again and the mini pump
activates, repeating the filling cycle.
Bolt displays the
status of automatic control process, as shown in Figure 2.
If you want to repeat
the experiment with completely empty container control, then the
user has a two-button
control (see Figure 1),
to empty or
fill the container.
For power supply of devices,
two AC/DC adapters are used, which can be
seen in the photo of Figure 1. The first supplies the
two mini water pumps 3 VDC at 1 ampere and
the second feeds the
system with a voltage of 7.5 VDC @ 300 ma.
Devices used in the project.
emulates what would be the cistern
and the red cap container,
the water tank that will be
filled. By means of
the pumps can be
repeat the experiment.
Top view of the devices. The Bolt
18F2550 microcontroller system uses its
LCD display to show the
status of the process. The microcontroller
receives digital sensor signal
on pin RC1
the auxiliary port,
while the relay terminals
(green) are connected to the mini
pump to activate the filling of the container.
Figure 3: View
of stainless steel level sensor.
It consists of a cylindrical piece with
its hollow interior, so that
the maximum level, by flotation, this piece
rises and opens the switch
Figure 4: The
sensor can be seen as a normally closed
switch, which opens when the water
level is reached. This signal is fed to the
auxiliary port. The mini
water pump is energized with 3 VDC,
by the microcontroller relay,
as shown in Fig.
Figure 5: The
electrical connections to
mini water pumps are shown here. Filling
any of the containers can be
done manually by means of two switches
(SW). In automatic mode, the relay
activates the filling pump.
Stainless steel RG-1045S water level switch