Wireless Effect Trigger

Beginning in August of 2011 I started exploring the idea of a wireless sound effect trigger. After researching various platforms to build off of, I eventually settled on the Arduino. Arduino is an open-source electronics platform for developing projects. They offer a variety of circuit boards with a micro-processor built in which can then be programmed using a free programing environment that users can download. I chose the Arduino not only because it of the vast amount of knowledge available online, but also because of the cost and the versatility of the platform. Most of the preassembled circuit boards cost no more than $30. The user can connect a wide variety of inputs and outputs to the Arduino to achieve the desired outcome. Programming an Arduino is relatively easy due to the vast amount of sample code and tutorials available through the knowledge base created by users.

I was eventually able to make a functional trigger system for about $70. The system I developed uses an Arduino Nano as the basis for transmitter. I chose this board since it is the smallest Arduino available with a built in USB connector for programming. The Nano is approximately 1.75” by 0.75”, so it is a small and compact unit. Connected to the Nano are a small push button switch and an inexpensive RF transmitter. The transmitter runs at 315 MHz and is matched to the receiver used on the base station. The Arduino is currently powered by a 9V battery, but can be powered by anything capable of outputting 7-12V. The receiver base station is built off of an Arduino Uno. I chose the Uno for this since it has plenty of inputs and outputs available without being overly large and it can be powered using an A.C. adapter. Connected to the Uno are the receiver unit, running at the same 315 MHz as the transmitter, and a MIDI cable for outputting control signals.

The system uses MIDI signals to trigger effects on any device with a MIDI input. When the push button connected to the transmitter is pressed, it then sends a number to the receiver based upon the number of times it has been pressed. The receiver interprets this signal and then outputs a MIDI Control value based on the number received. I tested the system using the sound system in the Drama Theater here at the University at Buffalo. I routed the MIDI signal to a Mini-Mac running Q-Lab with multiple effects set to respond to specific MIDI signals. When tested, the system worked flawlessly at ranges of up to 60 to 80 feet.

I feel like this system could be very useful. Being so versatile, it could be mounted inside of a prop in order to allow an actor to trigger an effect, or mounted somewhere in the set. It does not have to be limited to triggering audio however. It could be used to trigger anything capable of responding to MIDI signals.  I plan to continue developing this system over time to include more input options as well as improved capabilities.