type your circuit.
I purchased an Industrial
Control Enclosure from All
Electronics to house my project;
unfortunately, these are no longer
available. I recommend that you
first choose your PCB and other
components. You can then determine the size of the case needed
to enclose your circuit, transformer, and control relay.
My pool shed tends to leak,
so I wanted to make sure the
case was waterproof. I sealed all
holes with hot glue and made
sure all cables exited at the
bottom or underside of the case.
Figure 3. The new pool timer.
the littlecounter threshold.
In order for the Nemesis to do its
job, I needed to load it with a small
program. I say small because this
program only uses about one-twenti-eth of the available memory. (Go to
the Nuts & Volts website for the program code; www.nutsvolts.com)
The knob is read once each second and its values are checked against
internal timers. In order to get the
length of time needed, I used two
counters, the littlecounter and maincounter. Think of the littlecounter as
an inner counter. It is incremented
once each second, and, when it reaches 60, the maincounter is incremented.
By doing this, the maincounter
represents minutes. You can shorten
or lengthen this interval by changing
I’d like to conclude with a word
about safety. If you decide to build
this circuit, I can’t place enough
emphasis on how important it is to
use a CFGI outlet. If you are not
currently using a CFGI outlet, then I
recommend you install one.
The Nemesis is a very powerful
microcontroller and supports a high
level basic language as well as inline
assembly. I haven’t even touched on
the kinds of enhancements you could
add to this timer. The Nemesis also has
a command for controlling a TW523
X10 transceiver. By utilizing this device,
you could use an appliance module to
control the pump. Be sure to visit the
Kronos Robotics website for updates to
this and other articles. NV
Athena WorkBoard PCB
Athena WorkBoard Deluxe
7805 5 volt regulator
Athena Compiler Software
Source and Part Number
Kronos Robotics #16406
Kronos Robotics #16460
Kronos Robotics #16457
Kronos Robotics #16167
Kronos Robotics #16208
Kronos Robotics #16136
Free download from Kronos Robotics website.
Circle #77 on the Reader Service Card.