Croakers' Chronometer

About the project

Smile at the frogs and they will vibrate in a manner that can be translated into the current time.


Frogs "looking up" represent hours in binary (left to right; 8,4,2,1).

Frogs "looking forward" represent minutes in binary multiplied by five (left to right; 40, 20, 10, 5).

Smiles are detected by a Google AIY vision kit (camera behind the frog in the booth).

Frogs were made by my wife, Annelle, using polymer clay. They were part of the "Froggy World" project a few years ago.


Google AIY vision kit

(2) Arduino Uno

5 volt power supply (5 amp)

(8) micro motors (3 volt)

Pushbutton switch

Polymer clay

3d printed parts


(8) 2n3904 transistors

(8) 1n4007 diodes

(8) 100 ohm resistors

Photo resistor

1/4 inch plywood

(16) 3mm x 6mm screws




Files can be found here.

Step 1:

The Google AIY Vision kit includes smile detection in the default setup mode. The "hat" atop the cardboard Google assembly is a LED button that changes color when a smile is detected. A photo resistor can be used to detect that change. With "no face," I measured 12 K ohms across the photo resistor. With "face detected," 1.8 K shows up on the photo resistor. With "smile detected," .6 K is measured on the photo resistor.

Detecting a smile causes a relay to operate, providing power to the motors that shake the frogs.

Step 2:

Print and assemble the lilypad spacers.

Step 3:

Cut the top from plywood. Drill holes and paint.

Step 4:

Solder wire wrap wire to the motors.

Step 5:

Insert the motor into the canister.

Step 6:

Screw 3mm screws into the "wobbler."

Step 7:

Press the wobbler onto the motor shaft.

Step 8:

Run the motor wires through plastic bolts that have been inserted in the top of the lilypad.

Step 9:

These bolts prevent the cans from turning around and moving out of position when vibrating.

Step 10:

Insert the cans on the pad.

Step 11:

Glue a piece of wood to the lower lilypad base.

Step 12:

Add velcro to the wood and attach the lower and upper lilypads.

Step 13:

Wire according to the schematic diagram in step #2.

Step 14:

Place the cap over the top of the Google AIY Vision kit--we don't want ambient light to impact smile detection.

Step 15:

Secure the frogs using duct tape.

Step 16:

Velcro the "Smile Booth" to the lilypad--angled upward so that the camera will "see" someone looking at the clock.

Smile . . . then perform binary math and multiplication to tell the time :)


Photo of electrouser778


I am an author and electrical engineer.


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