Category Archives: Halloween

2014 Halloween project update

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.

2014 Arduino projects for Halloween

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…