Freezer thaw watch guard

After a longer absence from my home and freezer I was never secure that there was no power outage and the food was thawed and refrozen after the power was back.

The designed modul can help me in the future to detect a malfunction during my absence from my home. You can also use a electronic thermometer to check the min and max temperature, but I prefere a 3D printed tool.

What have I to do to prepare the watch guard:

1. Print the 3 parts (base, sensor and lock)
2. Insert two small Mini-Magnets (8*3) in the watch guard. One in the base, one in the sensor.
3. Insert the sensor in the hinge of the base
4. Insert the lock

Now the construction of the device is finished.

How I use it:

1. Close the sensor and the  base (against the small force of the magnets)
2. Close the lock
3. Fill the opening of the base with water and put it horizantal for 15 minutes in your freezer (do not overfill it)
4. After the water is frozen open the lock, the watch guard is now ready

How it works:

When the water freezes the sensor is bocked in the frozen water of the base, the force of the magnets is not strong enough to open the device.

When the water is thawed the senor will open. A good sign to see that there was a malfunction. I have tried it with different freezers to find out if it works and how much water the watch guard needs.

You need support material for the sensor and the base. 

I have designed the three PLA parts with Fusion 360 and used a Prusa slicer.

If you have no magnets you can try to use the guard in a different way. Open the sensor, fill die base with water, freeze the water, close the sensor. Now the sensor touches only the ice. If the ice thawed and freezed again, the sensor will sit in the ice. the function depends on the ease of movement of the parts.

If you want to use it for your freezer, test the function and use it on your own risk.