This hack allows you to play your own custom messages through an animatronic talking Hamster. If you are unfamiliar, these hamster toys repeat everything you say in a cute cartoonish animal voice while bobbing up and down. By replacing the hamster's microphone input with an audio feed from an Adafruit Audio FX board, and using a vibration switch as a trigger, you can have the hamster basically say any prerecorded message you want when you tap its nose. This makes for a fun and easy personalized gift for children of all ages.
While this isn't a difficult electronics project, it does require some knowledge of electronics and soldering. To learn about both, check out the Electronics Class.
Step 1: Materials
Step 2: Skin the Hamster
Remove the hamsters little furry pelt by cutting the small zip tie holding it to the inner hard plastic enclosure.
This can be found in the back of the hamster near the base.
Step 3: Open the Enclosure
Remove the screws holding the enclosure shut and set them aside for reassembly later.
Pull the back plastic shell away from the assembly to expose the circuit board.
Step 4: Drill a Hole
Drill a 3/16" hole in the back enclosure shell. This will be used to pass through the wires from the audio FX board.
Step 5: Wire the Switch
The vibration switch needs to be wired in parallel to a capacitor in order to debounce the switch and ensure a clean trigger of the audio board.
So, to begin, solder a lead from the capacitor to one on the switch, and then solder the other pair together.
Take note of which pair is wired to the ground stripe and the capacitor, and solder a 4" black wire to this pair.
Solder a 4" green wire to the other pair of leads.
Slide shrink tube over each solder joint and melt it into place.
Bend the capacitor backwards such that it is in-line with the vibration switch. Slide a piece of shrink tube over it and melt it into place to insulate the assembly and hold everything firmly in place.
Step 6: Record and Upload Audio
Record a sound clip using your audio recording application of choice. Mine is Audacity. It is free and relatively easy to use.
You can record up to 10 audio tracks.
Some considerations to keep in mind when recording audio is that if there is a break in audio that extends more than a second or two, the Hamster might drop some of the words after the break. Thus, try to prevent dramatic pauses. Also, the Hamster will wait for the entire clip to play before repeating, so it is advisable not to make the clip too long. Another thing to keep in mind is that if the audio is too quiet, the Hamster will assume it is just background noise and not repeat it. Finally, leave a few seconds of silence at the end of each audio clip. This gives the animatronic motion time to stop and prevents it from re-triggering the audio board at the end of the clip.
When you are happy with all of your audio, export them as .WAV files and with the following naming convention:
This naming convention will play the 10 files at random when pin 0 on the board gets grounded.
When all your files are saved, connect the Audio FX board to your computer via the USB port. It should show up as a regular hard drive. Simply copy your audio files onto the FX board and eject it from your computer.
Check out the full Audio FX board documentation if you are confused.
Step 7: Wire It Up
Connect the green wire from the switch assembly to pin 0 on the audio board, and the black wire to ground on the audio board.
Solder a 6" red wire to the Vin pin on the audio board.
Solder a 6" black wire to the ground pin on the audio board.
Solder a 6" green wire to the L (audio channel) pin on the audio board.
Solder a 6" black wire to the ground terminal next to the L terminal.
Step 8: Cut the Microphone Wires
Cut the red and black electret microphone wires away from the circuit board.
Step 9: Insert the Wires
Pass the four 6" wires from the audio board through the hole drilled in the plastic shell from the outside in.
Step 10: Power Wires
Solder the red power wire from the audio board to the same terminal on the hamster's circuit board that the red wire from the battery compartment is attached to.
Solder the black wire from the audio board to the terminal on the hamster's circuit board that the black wire from the battery compartment is attached to.
By doing this, when the power switch is toggled, it will turn on both the hamster's circuit board and the audio fx board.
Step 11: 1K Resistor
Solder a 1K resistor between the terminals that the microphone was previously attached to.
Step 12: Resistor and Capaictor
Solder a 10K resistor to the positive lead of a 10uF capacitor.
Bend back the negative lead of the capacitor and solder that to the 6" green wire from the audio board.
Finally, insulate most of this assembly with shrink tube, but leave the lead from the resistor sticking out the end.
Step 13: Wire the Rest
Solder the remaining 6" black wire from the audio FX board to the lead of the 1K resistor attached to the electret microphone's negative terminal on the hamster's circuit board.
Solder the unconnected 10K lead to the other side of the 1K resistor that is connected to the electret microphone's positive terminal on the hamster's circuit board.
Step 14: Hot Glue
Secure the resistor and capacitor to the surface of the circuit board with a little bit of hot glue. This will keep it in place and keep the connection from breaking.
Step 15: Close the Case
Reassemble the plastic casing using the screws you set aside earlier when you took it apart.
Step 16: Insulate the FX Board
Using a large 1" (or so) diameter piece of shrink tube, insulate the audio board to keep it from shorting, and to hold the wire securely in place.
Step 17: Insert
Insert the sensor into the hamster's cute little nose, and the audio board up into it's soft little head.
Slide the hamster's pelt back onto it's inner skeleton and use a new zip tie to secure it back into place.
Step 19: Insert Batteries
Insert batteries, close the lid, and turn your hamster on.
You're now done.