Can anyone recommend any good voice activation modules?
Check sparkfun.com they have quite a lot of stuf with example code.
I’ve used a “EasyVR” module. It’ve very limited compared with an smartphone’s voice recognition. Really the cheapest VR solution is likely a smartphone and a Bluetooth module. To use a smartphone this way you’d need to know how to program it correctly.
If you don’t want to use a smartphone then the EasyVR module is the way to go.