The Digital Energy Saver
files are on the Nuts & Volts website at www.
nutvolts.com If you don’t have a programmer, the
chip can be purchased along with a commercial
board. Although the board is simple enough to be
wire wrapped, it is better to use a printed circuit board.
There are two jumpers required if you etch a
single-sided board. Solder these first. Pay attention to the
polarity placement of the three diodes and the 220 µF
cap. Both the diodes and the resistors are placed standing
up for space consideration. R3 is a resistor network.
Make sure the common pin of the resistor net goes in
the location marked “pin-one.” The printed board layout
has extra holes, as capacitors come in different sizes. Also
there is an extra hole for the resistor net, allowing you to
use a 10-pin version.
When mounting the triac, hold the triac with
needle nosed pliers at the thick part of the lead and
bend the remainder of the leads down at right angles using
your fingers. Mount the triac with a 4-40 screw and
nut. Cut 6” of red, white, and black #18 stranded wire
and solder to the board to their respective locations. I
recommend using an 18-pin socket for the microprocessor
if you are going to change the programming of the
The switches come in different lengths. Using a
short one adds security against bumping and children,
but requires an instrument such as a pen or pencil to
turn it on. The 7 mm switch is ideal for a light switch
plate. The switch is soldered to the opposite side of the
component side of the board.
Before inserting the microprocessor, secure the
board from moving and connect 110 volts to the white
and black wire. The red wire is the switch’s 110 volts.
Measure the voltage between pins 5 and 13 of the
microcontroller. This should be a 5. 6 volts.
Figure 2. The parts on the PC board.
First, determine the number of seconds, minutes,
hours, or days you wish the appliance to be on. The
dipswitch is a binary switch, which counts in the base of
two. The first six switches program up to 63 units. The last
two sets of the switch provide counting in seconds,
minutes, hours, or days. It is easier to use the look up
table included on the website. For example, if you are
programming for a closet and you want the unit to time for
five minutes, set the switches as follows: 1 off, 2 on, 3 off,
4 on, 5 on, 6 on, 7 off, and 8 on.
Switch Plate Installation
The switch plate is made out of blank electrical box
cover. Do not use metal plates. When purchasing the plate,
Circle #134 on the Reader Service Card.