Uploaded November 2025 | Updated September 2026, 1 week ago

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In this third part of my Animatronic Frog series, I show how to control servos using the Adafruit 16-Channel PWM/Servo Driver (PCA9685) with a PICAXE microcontroller.

There’s almost no documentation online about using this board with a PICAXE, and it took me a lot of trial and error to figure out how to make the two communicate correctly over I²C.

In this video I cover:
• How the PCA9685 servo controller works
• How to wire it to a PICAXE (power, SDA/SCL, address lines)
• How to send I²C commands from a PICAXE to control any servo channel
• How this fits into my animatronic frog system

This servo controller is what physically brings the frog to life. After the MP3 player sends DTMF tones and the MT8870 decodes them, the PICAXE uses this board to animate the mouth, arms, body, and more.

Next video: Putting it all together — programming the frog’s behaviors.

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Parts used:
• Adafruit 16-Channel PWM/Servo Controller (PCA9685)
• PICAXE 14M2
• MT8870 DTMF Decoder
• SparkFun MP3 Player Shield (MY1690X-16S)
• Various micro servos

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