I have been sent a few things I will be using to make a prototype for the Halloween project. The main features will be playing audio on demand, and switching lights (or other 120V items) on and off in time to the audio. Here are the items I will be evaluating:
- MP3 Shield ($19.99) from CutiDigi.com. This shield has its own flash storage and lets you load MP3 files over from SD memory cards or USB thumb drives. In addition to control buttons on the shield itself (vol+/-, pref, next, play), it also has buttons to start up the copy operation and put the unit to sleep. There is a 1/8″ headphone style jack for getting audio out. It is controlled via serial (tx/rx) and can be made to play a specific track number off the memory.
- Relay Shield ($7.59) from e-Bay seller happyvalley009. This shield has four relays that can handle 120V up to 3amps, which is a small amount but enough for our needs. It is dangerous to run 120V in to a shield like this, as a short could really cause some problems. A better solution might be to use a separate relay board ($8.49 with Amazon Prime shipping) that is controlled without being attached to the Arduino itself. That would let it be physically separate and still be controlled the same way (and, this one can handle more amperage).
As soon as my funding source returns from vacation, we will order more items and begin working on a prototype.