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Asked — Edited
Resolved Resolved by joseph4760!

Sparkfun Mp3 Trigger

I purchased a MP3 Trigger for my Wall-e project. After building the trigger, I have connected a speaker, supplied power and it works. But when I connect it to the EZ-B board the trigger does not work. I have played around with the settings but with no luck. Do I need to use some particular naming convention for the MP3 files? This is the last piece to my Wall-e project and everything except this is working. Thanks in advance for your help!


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Hi Chrisb66,

Yes the files do need to be a certain format.

Can you manually cycle through your sounds with the on-board switch?

Are you sending serial commands via the EZ-B or using EZ-Script commands
-> MP3TriggerPlayTrack(D7, 38400, 164) ?

Do you have a pic of your connection to the MP3Trigger from the EZ-B?

Have you configured the init file for the MP3Trigger?

I use one of these boards on my big R2-D2. Once setup they work great.

I can help you through, just need more info.

Hi Kris,

When the MP3 trigger is not connected to the EZ-B and I supply power to the device, I am able to cycle through the sounds stored on the trigger. But when I connect it to the EZ-B, I can not get any of the recorded sounds to play. Either by cycling through them with the switch or with through the EZ-B software. I have set up the software to look for the D4 port that I plugged the trigger into and have tried various other settings with no luck. I have tried to plug the trigger into other ports, also with no luck.

Do I have to save the sound files using a specific type of name? Examples of names that I used: beep.mp3, hello.mp3. Is this okay?

Thanks for your help!
Also, I have tried to play the various sounds by selecting the buttons on the MP3 Trigger window and by using commands.
Hi Joseph4760,

Port: D4
Baud Rate: 38400

Thanks for the help!

First take a read through the MP3 Trigger manual. It outlines the basics,
such as what your files need to be named ect.

Linky -> MP3 Trigger Manual

Next, we need to know what your connection from the EZ-B to the MP3 Trigger is.
Can you tell me the exact pin to pin connections you are using?

Have you configured the MP3TRIGR.Ini file to match your baud rate and such?
Are you running the latest firmware on the MP3 Trigger? 2.53?

Also when you connect the EZ-B to the MP3 Trigger, are you powering it from
the EZ-B or External power?
I take it that you went through DJ's tutorial on the MP3 Trigger and wired yours according to DJ's instructio I ns?
If I remember correctly there is a switch on the MP3 Trigger. Toggle that switch to the other position and try it again.
If you power the trigger of the servo wire then you need to switch it to USB. There is a small switch on the board. For internal and USB power. I'm righting this on my phone. So if you need more help. Just ask. And by then I will have my PC infrot of me. LoL
One tiny thing that is often overlooked when connecting other powered devices to the EZ-B is that every self powered device MUST share a common ground with the EZ-B circuit board.
Thanks to everyone for your help (Robot-Doc, vhs896, joseph4760, and Lumpy. I flipped the switch to USB and now the board does play when connected to the EZ-B. Something I should have seen much, much earlier. Unfortunately the sound volume is very low. I am able to issue commands to trigger sounds and change the volume level. But between the volume levels 25-255 nothing is audible. Volume level 0-24 can be heard, but is not useful for my needs. Could the speaker that I am using be the problem? Thanks Again!
You might want to look into getting a small 5 volt pcb amplifier to boost the output audio level. An ebay or Amazon.com search will offer you many choices.
@chrisb66, I had that same problem as well. I also thought about getting a small amplifier, but opted instead for a mini rechargeable Bomb Speaker (about $8.00) that I got off of Amazon. It works really well, and can be very loud.
@chris like robodoc suggested the output is a low level output. It would work great for headphones:)

Here's a 38 watt amp from sparkfun if you want to keep with the same store.
This should be enough power for any speaker you use. 38 watts is 4 ohm so at 8ohm it's 18 watt output.
There is a great community here on EZ-Robot. Thanks to everyone for your help!
And the nerd will inherit the world... LoL