This project repurposes an old toy trivia game robot named 2-XL as a new face and voice for the Amazon Echo Dot. Vintage 2-XL units can be found used in thrift stores/ebay/etc - but the main idea here could easily be applied to other retro robot toys and similar items.
We'll replace 2-XL's innards with a Metro Arduino-compatible board, a Wave Shield for generating audio, and an Adafruit Proto Shield to accommodate a simple audio input amplifier.
The project uses code from Phil B's excellent Voice Changer guide.
The audio signal is sent from the Echo to the amplifier, and then from the amplifier to the Analog input of the Metro. The Metro then applies a pitch shift effect to the audio signal and outputs it via the Wave Shield's built-in DAC. The signal is then sent from the Wave Shield to the preexisting speaker in 2-XL's chassis.
Both LED eyes are controlled by a single pin on the Metro which allows them to be synchronized with the audio output.
The four buttons on 2-XL's front panel are wired to digital pins on the Metro, which allows them to trigger playback of audio samples stored on the Wave Shield's SD card.
Power is sourced from 2-XL's front panel jack and is turned on/off using the switch built into the preexisting volume pot. The volume potentiometer is not used in this guide but audio output could be wired through it if you prefer.
- Echo's mics are unable to here new commands while it's voice is being output through the voice effects generated by the Metro.
- Mounting the Echo inside 2-XL would have been preferable - but because of its built-in near-field microphones, the Echo needs to be mounted on the outside of the 2-XL enclosure.
- Amazon Echo Dot
- Adafruit Metro
- Adafruit Proto Shield
- LM386 audio amplifier IC
- SD Card for audio samples
- solid core and stranded wire
- 2 x 3mm red LEDs (for 2-XL replacement eyes)
- panel mount 3.5mm jack
- capacitors - 100uF x 3, 10uF x 2, 47nF, 0.1uF
- resistors - 20KΩ, 470Ω, 10Ω, 2.2KΩ, 150Ω, 56Ω
- 3.5mm audio cable
- adhesive velcro strips (for mounting Echo on 2-XL)
- soldering iron & solder
- clippers / flush cutter tool
- desoldering pump