Hacking an analog clock to sync with NTP - Part 3

Most battery-operated analog quartz clock on the market today are quite similarly internally. They are usually based on an oscillator driving a Lavet type stepper motor, Movement is made by alternating the current running through a copper coil in every step, followed by an interval without current so as to provide time for the magnetic gear to turn to its new position.

I am going to disassemble the Ikea clock and connect two jumper wires to the clock mechanism. These two wires will then be connected to the GPIO pins of the ESP-12 for ours to control.

To remove the plastic cover over the clock face, turn the clock over and disengage the 3 plastic tabs holding the cover using a flathead screwdriver.

Once that is done, pull out the second hand, followed by the minute then the hour hands.

With a butter knife (I used a plastic pry bar), gently pry the clock mechanism out of its holding cavity.

There are tabs on both sides of the clock mechanism holding the front and back halves together, which is easy to take apart.

When pulling the front and back halves apart, it is best to do it with the spindle always facing up to minimize the gears falling out all over the place and having to spend time fitting them back together. Also, take photos every step of the way to make it easier to fit the parts back later if needed.

The cluster on the right containing the copper coil is what we are interested in. If you look closely, the coil is actually connected to the two solder points at the front. When powered by a battery, alternating pulses will be applied by the osciallator (the metal tube) at those points, powering the copper coil and causing the tiny magnetic gear to rotate in steps.

What we want to do is to solder two jumper wires at those points so that we can power the copper coil at will.

I also used the soldering iron to create a small hole in the casing for one of the jumper wires to pass through.

Now it is time to put everything back together.I find it easier to place the magnetic gear upside down with the other gears:

then carefully invert the other half containing the coil onto this half, after carefully lining up all the holes and connectors.

At this point, it is best to check if everything has been assembled properly by fitting the second hand into the spindle and inserting an AA battery. If the second hand starts to tick as normal, the operation is a success!

Once the testing has been done, I can insert the clock mechanism back into the holding cavity. In order to accommodate for the new wires, I used the soldering iron to melt two holes at the side:

Then reinsert the plastic cover over the clock face, and we are done!

To be continued...


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