■ FIGURE 1. Bike Blinker schematic.
the temperature sensor and a single pushbutton switch
while operating the flashing LEDs. I have used this chip for
a number of model railroading projects and knew that it
had more than enough capability for this endeavor. I also
knew that the eight-pin 12F683 was available in a surface-mount package that would go a long way towards
meeting one of the objectives — making the unit as small
and lightweight as possible.
Solder the PIC12F683 to the circuit board; sure to
align pin 1 properly. To check the wiring, I like to program
the chip as soon as it is
mounted. Just connect
power (three to five volts
DC) to the board and
plug in a four pin header
programming will confirm
that the chip has been
Using the Serial
Output for Testing
■ PHOTO 6.
■ PHOTO 5.
Pin 7 and ground can be
connected to a PC’s serial
port for testing. The PIC’s pin
7 goes to pin 2 on the PC’s
DB9 serial port connector and
ground goes to pin 5 on the
DB9. On your PC, set
Hyper Terminal for 9600 baud, eight
bits, one stop bit and, no parity.
When power is applied to the
completed Bike Blinker, the version
number and current Celsius and
Fahrenheit temperatures should be
displayed (see Figure 2).
Comments in the PICBASIC PRO
program listing (available at
www.melabs.com) explain why the