Talking Alarm Clock
I've been playing around with the Voice Recorder IC's that were used on the Staples
Easy Button Mod. The uses seem endless, however one thing comes to mind.
From my childhood one of the toys that I remember really wasn't a toy - but a clock.
Yes, there was a talking "Masters of the Universe" alarm clock that had this really
obnoxious dialogue, which went something like:
"He Man, Its Teela
we've been called again
we must not let Skeletor
keep us from our friends."
"Then call with me Teela:
Its time to wake up
smile and be happy
brush your teeth
and make it snappy
we never fail with our wake up verse
because we're the Masters of the Universe."
Taking this track and retrofitting an ordinary digital alarm
clock would be great! As an added challenge, the retrofit must be done in
such a way that only the beeping sound is replaced (you can't always wake up to
Teela).
After a search on E-Bay, I was able to buy a clock that was broken (no audio and
alarm switch stuck on) for
$15.
After some prying at the clock face, I was able to get to the audio player.
This is definitely a time warp, as the only electrical component is the motor used
to spin a miniature record.
Notice the needle is attached to the base of the translucent speaker cone.
It's a mini-phonograph!
In the case of this clock, a rubber belt had slipped off of the motor spindle and
after this was reset, the clock could speak again! Here is a recording of
the clock, which was filtered via Audacity to remove some of the record crackle
and pop.
With the audio track finally obtained, the next phase is to get an appropriate alarm
clock to upgrade.
With this end in mind, I went to the local Target to get a "Cool looking" alarm
clock. The RCA model I chose had a simple display and a digital radio.
After bringing it home and popping it open I was horrified to see how this thing
was put together. There were multiple PCB's all
connected with a tangle of hand soldered wires. In addition, the lack of space
had them leaving long legs on the electrolytics and then hot gluing them to the
top of previously inserted components.
This has to be one of the worst designs for manufacturing. I can't believe
it even worked!
The New and Improved Talking Alarm Clock
After failing to find the perfect new clock, I turned to an old alarm clock that
was laying around. One of the drawbacks with choosing a clock that is a few
years old is finding datasheets for the parts it uses. It seems the two IC's
used in my Sony alarm clock (Radio Tuner Sony CXA1019 and the Clock Sanyo LM8560)
were discontinued. After some searching, a Japanese version of the radio IC
datasheet was found.
After tracking down the alarm outputs from the Sanyo IC, the basic principal for
the clock was mapped out. There are 2 alarm outputs: The first is the
output set when the alarm time is reached - with the option of listening to a beeping
sound or the radio. The second is the sleep timer, and is usually set to leave
the radio on for up to an hour. Our focus is on the alarm output, as one of
the premises of this project was to keep the alarm clock as functional as possible.
The operation of the radio and beeper is a little tricky. The beeper is always
present, however the duty cycle is such that with a relatively small capacitor,
a general purpose NPN can be biased to enable the Sony radio IC's gain control. Looking at the alarm
output on the, the LM8560 functions approximately the same was as the
Sanyo LC85632, which has a much better data sheet (shown below).
The fact that the
radio is always enabled explains why you can sometimes hear
a little bit of the radio playing on some alarm clocks even when only the beeper
was selected.
A separate line into the radio IC (which I will assume is a line in since I can't
read Japanese) also delivers the beeping signal but with a chip resistor for the
volume control. This signal was measured at 40mV Pk-Pk so the retrofit will
attempt to duplicate these levels. It is interesting to note that the clock uses the 60Hz AC signal
to keep time. When the battery backup is engaged, an external oscillator is
used (and why the clock will be a few minutes off after running on battery power
for a while).
Now that the basic operation of the clock is understood,
a location to tap into
the circuit is needed. Power, ground, line input, and a switch output are
needed. This part proved most tedious, as the lack of documentation hurt.
Starting at the alarm selector switch, the output line was traced to where the beeper
went into the line in on the Radio IC. By copying the same circuit for
switching based on the duty cycle of the alarm, the enable for the sound track was
obtained. Finally, the power and ground pins for the Sony Radio IC were tapped.
Unfortunately, the DC regulation on the board is pretty simple and seems to vary
quite a bit. In addition, the IC's that Sony used can withstand voltages >
7VDC, while the Winbond chip tops out around 5.5VDC. Consequently, a 3.3VDC
regulator was chosen to keep the voice module functioning. A 4 pin connector
was used to tie the alarm clock into the voice module.
A PCB was created with the help of a friend (Thanks Monte!) that captured the requirements
above along with those of the Easy Button Mod project.
Since the message in the clock will not be changed often, the buttons necessary
to program the Windbond chip were placed on an external header. The round
PCB for the voice module fits in the clock thanks to Sony's
cubic design. The programmed voice module was screwed into the plastic
housing for the alarm clock, the interface connected and the clock re-assembled.
The He-Man clock will now live on in the digital age (or at least until it drives
me nuts and I'm forced to throw it across the room)!