year. There are 3,600 seconds per hour:
However, on for only .1 seconds = 5 mA hrs 0.1 = . 23 mA hrs
A negligible amount of power goes to an alkaline C
cell which has about 6,000– 8,000 mA hours. However,
the flash still catches the eye.
Building the GPS
Solder the PIC16F916, noting pin 1 goes to the
square pad. Solder the LCD and the switch. Solder the
three 1.0 µF capacitors. These do not have polarity due to
their voltages and construction. Solder the voltage
regulator, noting its flat rotation to the silkscreen.
Pass the battery holder wires through the strain hole;
solder the red wire to the positive pad and the black to
the negative pad. Cut the black wire to the same length as
the red one. The remaining wire will be used to connect
the battery holders.
Using one of the 3/8” spacers, place it next to the
LED to establish its height. Solder the bi-colored LED to
the board with the long lead going to the square hole.
Refer to Figure 1.
Go to the article link and download the GPS
template. Cut out the template and glue it to the top of
the box using a glue stick. Drill the four holes as indicated.
Use hot water to remove the template. Place the two-battery holder into the bottom of the box. Remove the
two posts either using a mill or a Moto tool for placement
of the single C holder. Refer to Figure 2.
Solder a short piece of wire from the positive terminal
of the single C holder to the negative terminal of the
double C holder. Solder the black wire coming from the
board to the negative terminal of the single holder and the
red wire to the positive terminal of the double holder. Use
double-sided tape to attach the holders to the bottom of
the box. Refer to Figure 3.
Put two 5/8” 6-32 screws through the top of the box
and turn it over. Add two 3/8” spacers to the screws.
Attach the screws into the board; the board should self-tap.
Using the GPS
Add three alkaline C batteries, noting their polarity.
Push the switch. The timer will count upward with hours,
minutes, and seconds. The LED should blink green. To
reset the unit, hold down the button until the display
I love coffee, I love tea, I love Nuts & Volts as it is
good for me. NV
November 2015 47
■ FIGURE 1. Coffee GPS board.
■ FIGURE 2. C holder placement.
■ FIGURE 3. Milled out posts.
1200 seconds x 7 mA
3 second interval = = 2. 3 mA hrs