MP3Trigger Sound

The MP3Trigger setup is the easiest way to add sound to your droid and control it via the R2 Touch iPhone app.

MP3Trigger sound requires
- An up to date version of the R2 Touch app (version 1.2 or higher)
- An up to date version of the MarcDuino Master: Firmware 1.6
or higher  (PanelController_MP3Trigger_v1.6.hex)
- A sound card in the MP3Trigger where you unzipped ALL the files in this archive available from the bottom of this page.

Setting up the MP3Trigger board

The MP3Trigger boards are available from Sparkfun:

First, you will need to purchase a MicroSD or MicroSDHC card (a 1 or 2 Gb is enough, but I use an 8Gb), and copy all the files (including the .txt file) from the sound zip file available at the bottom of this page. The order you copy the files in is unimportant. However, the number and dash at the beginning of the names of the files are important - don't change this number prefix. This is what the MarcDuino and R2 Touch use to play the right file.

Then you need to hook up the board to a MarcDuino main (panel controller) board as follows. The MarcDuino controller has to be loaded with the firmware version that is specific to the MP3Trigger sound (the other version if for the CF-III sound).

Here is a video that explains how to do the hook-up:

Adding Speakers

The MP3Trigger can only drive earphones directly. For speaker sound, you'll need either an amplified speaker (the easiest), or use an amplifier board. I use this Sure 2x15W cheap one with good success:

For just $5 more you have a 2x25W:

Customizing the sounds

The sounds are triggered by the number prefix in the filename. You can call them anything you want, but the number prefix has to be right for it to play with the R2 Touch app. They are bunched in banks of 25, which correspond to the R2 Touch buttons. In practice, since there are only 22 keypad buttons in R2 Touch, you can only access the first 22 sounds of each bank:

Files named 001-xxx to 025-xxx: Generic Sounds (i.e. triggered by the "Gen" buttons on the R2-Touch app).

026-xxx to 050-xxx: Chatty Sounds

051-xxx to 075-xxx: Happy Sounds

076-xxx to 100-xxx: Sad Sounds

101-xxx to 125-xxx: Whistle Sounds

126-xxx to 150-xxx: Scream Sounds

151-xxx to 175-xxx: Leia Sounds

176-xxx to 200-xxx: Music Sounds

255-xxx: Startup Sound

The flash image comes with 64 sounds, but is devoid of commercial music. The few music files I put there are placeholders (a beep version of Star Wars and of the Imperial March). You will probably want to replace these files with purchased music, and add some more music files of your own. To replace, just keep the same file name and overwrite the file with your own MP3. If you want to add more sounds, add them in sequence in each bank using the naming scheme outlined above.

You will be able to access additional sounds via the R2 Touch keyboard buttons. However for the 4 lower banks, additional sounds will not play using the auto modes (see below), which is limited to the original number of sounds that come with the flash image. If you want to use the random auto and bank modes with your custom sounds on the four lower banks, replace existing sound files instead.

Random Auto and Bank modes

The R2 Touch App can directly trigger any specific sound using the keypad buttons. It also has a Random Auto mode (the center round button), and a Bank mode (the outer circle buttons). Bank buttons behaves slightly differently depending on the sound bank, read below if you care about the details.

  • The keypad buttons work in conjunction with the numbering scheme explained above. 
  • Press the circular bank buttons once to change the keypad to the appropriate bank.
  • For the Gen, Chat, Happy and Sad banks, pressing the circular "bank" button a second time (or pressing once more if the bank is already selected) will play the next sound in the bank. Use this to generate a random sound of the right "mood". Pressing repeatedly will cycle up to the number of bank sounds pre-loaded in the default flash image. It will not access added sounds unless you modify the MarcDuino code.
  • The 4 "special effect" banks (Whis, Sing, Leia and Mus) behave differently. Pressing these bank buttons will always play the first sound in the bank. This is setup to guarantee quick access to four precise special effect sounds: a whistle, a scream, the long leia message and the cantina music. You can change these default sounds by replacing the the first sound file in the appropriate bank. Other sounds in these banks must be accessed via their specific keypad buttons.
  • The auto random mode is actuated by pressing the round Auto button in the center. It will play random sounds at random intervals. Only sounds from the first five banks (from Gen, up to and including "whistle") will be played (i.e. never from Sing, Leia or Music). It will also limit itself in each bank to the number of sounds that come in the default flash image, even if you add more sounds.

Curious Marc,
Nov 3, 2013, 5:04 PM