I have been tasked with creating two control systems for some Halloween attractions this year. I have a small budget for building the prototypes, and if they work, then I will be building a dozen or so of the units. I thought it might be fun to document the entire process here.

There are two projects:

1. A device will sense motion, then begin playing sound and toggle four outlets in a sequence that goes along with the audio.

2. A device will sense its location, and play a specific sound based on that location. It will have a fallback mode where buttons will trigger the sounds, for manual operation.

I plan to use low-cost Arduinos since there are many add-on Shields available for it to handle things like this.

Audio could be played in high quality using a cheap ($20) MP3 add-on, or, with a small amount of hardware (and a cheap SD card reader), lower quality audio can be played directly by the Arduino.

For triggering, the I/O pins will be used, hooked to a motion sensor. For the proximity sensor, I am researching iBeacon style tech (BLE, bluetooth low energy) or IR (infrared). Right now, it seems we could use cheap IR remotes, with a button taped down beaming and endless pulse. The Arduino can hook up a $1 IR receiver and software could decode the pulses to see which zone it is in.

For the outlets, there are $8 high voltage relay boards that can be wired to the Arduino’s Digital Out pins, and even a cheap $7.50 4-channel relay shield that can handle 120 volts 3 amps on each relay. The Shield is a nice idea, but dumping 120V in to the Arduino could be a problem if there was any kind of short.

I will document the various products I have found so far, soon.

To be continue…