problem, I manually go to any cell with
a duplicate number and put in a differ-
ent one. Not a great solution, but it works.
■ FIGURE 6
■ FIGURE 5
easily be cut out and used as separate cards.
The spreadsheet gets its numbers from an Excel command
— RANDBETWEEN(X,Y) — which fills that cell with a random number between the two values, X and Y. You can
make the spreadsheet recalculate all the cells and fill them
in with new numbers by pressing F9.
The only drawback to the program is it produces
duplicate numbers within the columns; i.e., the “B” column
could contain any number between 1 and 15, but there is
nothing to prevent duplicate numbers in that range. It may
be possible to solve this problem using Visual Basic, unfortunately, I am not familiar with this program. I imagine there
are Nuts & Volts readers who are. To solve the immediate
Although I have provided a printed circuit board
layout with the other project files, I constructed my
PCB manually using fingernail polish as an etch resist
medium. It works quite well, and it is easy to correct
any mistakes prior to etching the PCB. The layout and
wiring are not critical, and the project could easily be
done on a proto board using point-to-point wiring.
Figures 5 and 6 show the completed project. I built my
BINGO player inside a Tupperware-type container. It was
easy to fabricate and the unit looks quite novel. It runs on a
standard nine-volt battery and draws about nine milliamps.
The power is routed through an LCD so it is easy to see
when the unit is turned on. To start a new game, simply turn
the unit off, then on again.
This project could be improved by using a larger LED
display that would make its visual presentation much more
striking. The programming would have to change to accom-