Figure 2. Telematics Transmitter Board.
transmitter unit mounts on the
Hydrocar’s reversible fuel cell and
has terminals that attach to the fuel
cell, the solar panel, and the motor.
There is also an ON-OFF switch that
controls both the electrolysis function
of the fuel cell (OFF), as well as
switching over to power the
transmitter electronics and motor
after enough hydrogen has been
created (ON). When the switch is
OFF, voltage from the solar panel
flows into the reversible fuel cell to
allow the water to be split into
hydrogen and oxygen (Figure 4).
Substitute a three volt battery for the
solar panel if you want the
electrolysis process to go faster.
When enough hydrogen is
generated, switching to the ON
position cuts out the solar panel to
the fuel cell connection and cuts in
the fuel cell connection to the motor.
It also applies power from a standard
1.5 AAA battery to power the
transmitter electronics. The 1.5 volts
is stepped up to 3. 3 volts with an
onboard DC-to-DC converter circuit.
I’m also testing two 1.5 Farad super
capacitors in parallel (C3 and C4) to
replace the 1.5 volt AAA battery, but
my test results are not ready at this
I designed the transmitter board
with separate terminals for the solar
panel, fuel cell, and motor to
eliminate all the time-consuming and
confusing hookups that come with
applying the solar panel to the fuel
cell for electrolysis, then tearing this
down to hook it up to the motor, etc.
One ON-OFF switch does it all for
you, and you’re off and running
doing the experiments in no time.
The receiver is simply another
connected to an
chip that, in turn, is
connected to the computer with a
USB cable (Figure 5). Data from the
Hydrocar’s transmitter is received
and sent to the REEL Power software
where all the electrical parameters
are plotted as we shall see next.
Figure 3. Telematics Receiver Board.
the Telematics Car
If you’ve ever wanted to “really
know” what kind of electrical
performance a model car expends
while it rolls across the floor and up
and down ramps, the telematics car
will show you. I think you’ll be both
surprised and amazed at what
happens — even if our Hydrocar
doesn’t do wheelies. So, let’s start at
the beginning by preparing to
electrolyze some water into hydrogen
fuel for our reversible fuel cell. Fill
both cylinders to the 20 ml mark
with distilled water and remember to
correctly hydrate the fuel cell.
ZigBee — or officially IEEE 802.15.4 —
is a low-cost, low-power, wireless mesh
networking proprietary standard. The low
cost allows the technology to be widely
deployed in wireless control and
monitoring applications, and the low
power usage allows longer life with
smaller batteries. The mesh networking
provides high reliability and larger range.
The ZigBee Alliance is an association of
companies working together to enable
reliable, cost-effective, low-power,
wirelessly networked, monitoring and
control products based on an open global
standard. The most popular applications
• Home Automation
• ZigBee Smart Energy 1.0/2.0
July 2010 39