This board has been in development for quite some time. One of the holdups was finding suitable MP3 playback modules. The ones we used take a standard SD card and play files in the .MP3 format. You simply record the sounds you want onto 2 x standard SD memory cards and plug the cards into the players.
This board has two players that are both stereo and have seperate volume controls. The outputs are mixed together and fed to both line out sockets (to enable the use of an external amplifier) and the onboard stereo amplifier chip.
The board can be powered by almost any secondary voltage found in most EM machines (20~50V AC or DC) ar a 12V plug pack.
It has eight inputs to trigger seperate short sounds and four to trigger longer background music. This allows a background theme or longer sound file to be run while seperate sounds for bumpers or gun shots are superimposed over the background music - both with their own volume control.
The inputs are designed to be wired directly across a coil (solenoid or relay) with any voltage from 5V~50V AC or DC being suitable. They can also be configured to be triggered from a normally open switch.
Here is the first prototype nearly assembled:
I have parts for these in my current container due in port late next week so, allowing some shipping time to Cairns and then assembly time, I should have finished units ready in about a month. Price is as yet unknown but they won't be cheap....I plan to have them available in single and dual player models to make a cheaper option available.
Here is the prototype working:
