Step-by-step Fox Transmitter Controller
Based on the Montreal Foxbox by
François Tremblay VE2JX and Jacques Brodeur VE2EMM.
By Charles Scharlau, NZØI
Introduction
Here's some information to make fox hunting
more fun when you're the one hiding the transmitters. It's always more
fun if you can use an automated fox transmitter that will operate unattended.
I recommend using a battery-powered transmitter (an old crystal controlled
HT will do) and a Montreal Foxhunt Controller. The controller can be built
for less than $20; this includes the printed circuit board, and all the
parts to put on it. Details of the Montreal Fox Controller are available
at the sites listed below. Included is some special software for making
the foxhunt controller do some new tricks. Getting your PIC programmed,
if you don't have a friend with a programmer, is only a little tricky.
But there's LOTS of information available on the Internet that will help
you program your PIC 16F84.
Step 1: Learn more about the Fox Controller
The Montreal Fox Controller, featured in
73
Magazine's "Homing In" column for April 1998, is an inexpensive and
easy-to-build controller that can turn most any handy-talky into an international-style
fox transmitter. Jacques and François do an excellent job of describing
their Montreal Foxbox, including a schematic, on their website at <http://www.qsl.net/ve2emm/index.html>.
You should definitely make their web site your first destination if you
are considering building the fox transmitter controller described below.
Equally informative is the web page which
Joe Moell, KØOV, has dedicated to the Montreal Controller. Make
it your second destination: <http://members.aol.com/joek0ov/mfcupdate.html>.
Step 2: Parts
Here is a list of all the parts needed to
build a complete Montreal Fox Controller. The list is divided into two
parts. List I contains those parts that are not likely to be found in the
average junk box. These parts you will probably need to mail order.
List I: Uncommon Parts
| Description |
Digi-Key Part# |
Qty Needed |
| Printed Circuit Board |
n/a |
1 |
| PIC Processor* |
PIC16F84-10/P-ND |
1 |
| 18-pin DIP socket |
AE7218-ND |
1 |
| DIP switch (9 pos) |
CKN3008-ND |
1 |
| 4.19 MHz Crystal |
CTX007-ND |
1 |
| 10K Pot |
3386P-103-ND |
1 |
| 5V Regulator |
LM78L05ACZ-ND |
1 |
| 22 pF low-temp-coef 5% cap |
P4841-ND |
2 |
List II contains those parts that are fairly
common. You might want to try to scrounge the parts listed in List II before
resorting to buying them new.
List II: Parts to scrounge
| Description |
Digi-Key Part# |
Qty Needed |
| 10K resistor |
|
2 |
| 4.7K resistor |
|
1 |
| 1K resistor |
|
1 |
| 47K resistor |
|
1 |
| 100K resistor |
|
1 |
| 6.8K resistor |
|
2 |
| 0.1 µF cap |
|
5 |
| 0.01 µF cap |
|
2 |
| SPST mom. cont. |
|
2 |
| 1N4148 diode |
|
5 |
| 2N2222 transistor |
PN2222ADICT-ND |
2 |
| LED |
67-1106-ND |
1 |
Other parts you may want or need: battery,
battery holder and connector, wires & connectors to connect the controller
to your HT, chassis box, PCB mounting hardware.
Step 3: Programming the PIC
Jacques provides some sources of PIC information
(i.e., Microchip Corporation) and at least one supplier for PIC programmers:
<http://www.qsl.net/ve2emm/outilpic/pictools.html>
An inexpensive way to program the PIC16F84
is to modify a Montreal Fox Controller circuit board so that it can program
the PIC in circuit. The so-called No Parts PIC Programmer can be
wired directly to the modified Fox Controller circuit board allowing the
PIC to be programmed and then tested without having to remove the PIC from
its socket. This is especially handy if you ever write software for the
PIC, or make modifications to the Montreal Fox Controller software. You'll
be able to quickly make changes to the software, assemble it, program it
into the PIC, and then test it.
Many electronics projects have been designed
using the PIC16F84 processor. Having a way to program them will open up
a world of new project possibilities. So, if you enjoy building small electronics
projects, the afternoon spent turning a Montreal Fox Controller into an
in-circuit PIC programmer is time well spent.
Step 4: New Software for the Montreal Controller
If you are planning to modify Jacque's original
software for this project, and you are a native English speaker, you might
appreciate this English translation of the Montreal Fox Controller assembly
code:
FOXBOX2.ASM
FOXBOX2.HEX
If you have an interest in making the Montreal
Controller use shorter transmit intervals, then this new version of the
Fox Controller for ROCA-style hunts might be of interest:
ROCAFOX.ASM
ROCAFOX.HEX
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