Created in collaboration with Jamie Robertson, the MP3 Trigger is quite possibly the most versatile, low-cost, low power embedded MP3 Player. The board has 18 external trigger pins that will directly trigger pre-selected MP3 tracks, and a full-duplex serial control port that provides full transport control, remote triggering for up to 256 tracks, and fast real-time volume control. The board plays the MP3 files directly from a FAT16 microSD flash card and supports 192Kbps stereo playback. There is also an on-board navigation switch for local access and playback of all MP3 tracks on the flash card.

Alan Bond has interfaced this board to a radio receiver to allow use in radio controlled models such as boats. See details of his project in the 'Your Projects' section above, it's called '8 ch MP3 Sound Unit'.

New for Version 2: Aside from more than doubling the number of trigger inputs, the MP3 Trigger v2 now contains a resident bootloader that enables firmware updates directly from the microSD card without requiring a hardware programmer. The PSoC Designer IDE can be used to generate hex files for the bootloader. See the datasheet below for more details on how to use the bootloader.

The board uses a Cypress PSoC CY8C29466-24SXI microcontroller and a VLSI VS1053 audio codec.

Board can be powered by an external wall wart, FTDI Basic, or raw 3.3V input (see related items below).

NOTE: If you purchased an MP3 Trigger V2 before May 1, 2010, please update your firmware to version 2.10 below. This update addresses an issue with the serial control port baud rate. Please note that there are three different downloads: One for the standard serial baud rate of 38.4 kbaud, as well as one each for 9600 baud and 2400 baud.

These files are only for MP3 Trigger V2, not for the older original model, which does not require an update. Here are the hex files.

1. v2.10 38.4k baud
2. v2.10 9600 baud
3. v2.10 2400 baud

Instructions on how to update your V2 firmware are in the datasheet, but here’s a quick review:

1) Download and unzip one of the files above.

2) Copy the resulting hex file to a microSD card and rename it to: “MP3TRIGR.HEX”. It does not need to be the only file on the card – it just needs to have that precise filename.

3) Insert the microSD card into your MP3 Trigger V2 and turn the power on while holding down the center navigation switch.

4) Wait for the Status LED to go solid, then cycle the power. You’re now running the new firmware.

Please refer to the datasheet for a more detailed description of the Status LED indications when running the bootloader.

5) Please read the document "VLSI Application Note for protecting analog outputs V2" from the 'Downloads' tab as there are restrictions when connecting to amplifiers with common ground connections (the GBUF pin is biased internally at 1.25V)

Features:

• Input voltage: 4.5-12VDC
• Current Consumption: 45mA idle, 85mA playing
• File system: FAT16
• Audio out: line level stereo (1/8" stereo jack), see app note below if connecting to larger stereo jack
• Trigger inputs: 3.3-5V, active low inputs with internal pull-ups
• Serial: Full duplex, 8N1, 38.4K baud