Add an On-Off Switch to your Talking Timer
by Miami Mike, 02/05/2012.
This project was originally described on
. Revisions have been made since then and are still
ongoing, so please refer to this web page for the latest
Talking Timers similar to this one are very popular down
here in Florida. We use them in our thermal duration
contests and for practice. They're available from
for as little as $15 or so.
One problem I've had with mine is that there's no easy way
to turn it off. The battery drain is very low, but if you
leave it running long enough you'll find the batteries dead
when you need it for a contest. Over the years I've learned
to remove the batteries between contests so that they'll
last longer, but I came up with an alternative. It's a
modification that doesn't take very long to do.
The timer has a switch at the lower-left labeled "REPEAT",
with selections labeled "YES" and "NO." With "YES"
selected, as soon as the timer counts down to zero it
starts over again at the previous start time. I figure the
feature is meant for cooking when you have to stir the pot
at regular intervals, or something like that. At any rate,
I haven't found it very useful for our purposes so I turned
it into an on-off switch. Now, selecting "YES" turns the
timer on and "NO" turns it off.
To do this modification you'll need a small jeweler's
Philips screwdriver, a few inches of
wire strippers, an Exacto knife, and soldering equipment.
You might also want to start out with new
batteries so that you'll (probably) never need to
change them again.
Step 1 - Open the case.
Remove the battery cover and batteries, then remove the
four screws and open the case while the front is facing
downward, being careful not to break the speaker wires.
Examine the bottom of the PC board, then scroll down to
Step 5 and make sure it looks like one of
the two types shown there. If it does then proceed to Step
2. If not, you have a type that I haven't seen yet and
these instructions won't work for you.
Step 2 - Remove the 5 screws holding the PC board.
Step 3 - Carefully remove the PC board.
Gently pry the small PC board on the side of the
main board loose from its plastic slot, being careful
not to flex the solder connections to the main board,
and then remove the board assembly. Set it next to the
bottom half of the case so that you don't have to
disconnect the speaker wires.
Step 4 - Set the top of the case aside.
If the rubber membrane sticks to the top of the PC board,
peel it loose and put it back inside the top half of the
case in the correct position. Notice that in the picture,
the membrane is backward. The corner notch belongs against
the edge of the case.
Keep all of the plastic pieces and the glass display with
its foam strip in their proper positions inside the top
half of the case, and set it aside.
Step 5 - Identify the type of PC board you
So far, I've encountered two types of PC boards, which
I call "Type A" and "Type B." My guess is that Type A is
the most common and Type B is a copy of Type A. You can
tell them apart by listening to the speech. (Type A
has better sound quality.) To continue, examine the
pictures below and click on the type of PC board that you
Talking Timer PC Board, Type B
To continue, click on the type of PC board that you have.