Mp3 player with sound sensor that plays random or sequential tracks


I’m new to LittleBits and a total newbie.

What I would want is that my doll when spoken to,
triggers an mp3 player and plays a random track from the sd card.
I have 8 sound files in total.

I’ve seen a video of something that was close.

And from what I could tell, I need…

  • Mp3 player bit
  • Sound sensor bit
  • Power bit ( battery powered )
  • Speaker
    Probably other stuff, but since I’m a total newbie… :wink:

I also would like that it has some sort of delay,
what I mean by that is that there would be a delay instead of playing back a track right away.
Is this possible ?
Also is it possible to have a random track played each time ?
If not, I hope there is a possibility for sequential playback ?

Can anyone help me choose the right components and also I know nothing about coding,
so I hope anyone can help with that as well.

Thanks in advance for any info.


Can the mp3 player bit be used with another speaker, besides the synth speaker, like a regular speaker ?

For example, like this one :

Thanks in advance.

For the sound delay part, can the “timeout Bit”, maybe be used to achieve this ?

and then there wouldn’t be any coding necessary I think, so no need for an Arduino bit.

So the complete setup would be something like this -

Power 9volt bit --> Optional on/off Toggle switch bit --> Sound Trigger Bit --> Timeout Bit --> Mp3 player bit --> my best guess would be then to connect a speaker to the headphone jack, should be possbile, right ?
Or else there’s maybe a way to dismantle the synth speaker, and only use the speaker part without the housing ?

Does that sound about right ?
Hopefully the delay I’m looking for can be achieved by the Timeout bit ?
And would the sound trigger be triggered by the sound coming from the speaker and start some sort of loop ?
If so, is there a way around that, or does the time-out bit take care of that ?

Thanks in advance for any info.

I did a quick mockup in Photoshop.

For example if the timer is at 10 seconds and in those 10 seconds it detects another sound,
will the timer reset or not ?

For example if I would say a phrase of 3 words, would it detect that as 3 different triggers and thereby trigger the timeout module 3 times ?

Another idea is -

(which is a player with 200seconds of memory,includes a speaker and plays track sequentially when you push the button.)

to connect it to the sound sensor somehow, I don’t know if that’s even possible.
The way I thought it might work was to remove the pushbutton from the wires and connect that wire maybe to a bitsnap or proto bit and in turn connect that to the timeout bit.

If that were to be possbile, that would eliminate the need for the mp3 player bit and speaker.

Hopefully the experts in here can provide some insight…

I also have another idea, but I don’t know if that is possible -

Can the power bit be turned on wireless, perhaps with the remote trigger bit,
instead of using the slide switch or toggle switch to turn it on or off ?

Hi @Soxbrother,
welcome to the forum !
I have some answers to your first post:
It is possible to trigger the mp3 player by speaking to it. As you mentioned, it can be done including a delay.
I tested the following setup and it worked:
power bit-sound trigger-timeout-mp3 player-wire-synth speaker.
Set the sound trigger to medium sensitivity, the time out bit to ON-OFF and the mp3 player to play the next sound.
It is not possible to play sounds random, only sequential.
I added the wire to avoid that the sound from the speaker triggers the mp3 player.
The timeout bit delays appr. 3 seconds in my setup.
No coding needed.

Your second post:
The external connection on the synth speaker only works with a headphone or as output for an external amplifier, not with a speaker as you showed. It results in a very low sound level.

Your third post:
You can connect an external amplifier to the synth speaker. I added a wire as described to increase the distance between the sound trigger bit and the speaker to avoid a loop. The timeout bit itself does not avoid a loop,
I think you can damage the synth speaker bit if you remove the little white speaker and replace it by another type. Not recommended to do so…

Your fourth post:
During the time delay a new trigger will not be detected.
You can test its behaviour by mounting a led bit after the sound trigger bit and experiment with the setting.

Your fifth post:
The sound trigger sends a 5 volt DC pulse.
you could connect this pulse to an external system with a proto bit. Maybe it works, but there is a risk to damage the sound trigger this way…

Your sixth post:
I do not have a remote trigger bit but I tried the w30 ble bit and it worked. I placed it between the power bit and the sound trigger and then the system only worked when the ble bit was activated via the purple button or the slider on my cellphone app. So I think the remote trigger bit will also work like this.

Hi Alex,
Thanks for the very useful info !!!
And thanks for testing my future setup with your bits !!

I also have discussed this with the customer service.

And came with up with a solution myself.
You said something like it in your reply.

My solution is as follows (copied from support page) :

"In my new solution, the Timeout bit would be in on/off mode,
e.g. the duration of a sound file is 6 sec., so if I want a delay before the sound file starts, I can set the Timeout bit to maybe 11sec. (look below for why it’s 11 sec.)
So when the sound sensor gets triggered, the Timeout bit will send a continuous “on” signal for 11 seconds and then plays the sound file.

Since the Timeout Bit sends a continuous “on” signal for 11 seconds,
in that time frame, every sound the sound trigger would pick up, will be ignored,
because the state that the Timeout bit is in can’t be changed while it’s working.

So why 11 seconds then, well that’s quite simple, in the example the duration of the sound file was 6 seconds.
So let’s say we want a delay of 5 seconds, that would be 11 seconds total.
So we must edit all the sound files to include the 5 seconds of silence at the beginning of the sound file.
So in the end the sound file from the example would be 11 seconds in length, 5 seconds of silence and then the 6sec. sound.
Off course if you have multiple sound files, you’d have to see what is the longest sound file in length and make all other sound file the same in length.
I didn’t check my sound files yet to see how much the durations differ,
so hopefully they all have somewhat the same duration."

In regards to the random playing of the mp3 player,
I have read here on the forum about a possible solution that uses the pulse bit.
You would set the pulse bit so that it sends 2 pulses, so then the mp3 player plays the second track and then the 4th track,… or whatever number of pulses you like.
( You need to start your sound file with a second or 2 silence with this method, because otherwise you hear the mp3 player play the tracks for a second while it skips through them !! )

But maybe there is another way, although I can’t test if this works because I don’t have any bits, yet.

The setup would look like this -
Power bit 9v - Sound Sensor - Timeout bit - Random Bit - Pulse bit - Mp3 player

So the idea in theory is that the Random bit would send a random signal to the pulse bit and then the pulse bit would send a random pulse every time. ( Again it’s just a theory )

In regards to the speaker -
Can the synth speaker be dismantled, so that you just have the speaker without the housing ?

Hi @Soxbrother,
the random bit makes random noise or generates a random voltage between 0 and 5 volt DC when activated.
Sadly the pulse bit does not react on this, it just needs a trigger of 5 volt DC at its input to start making pulses. The number of pulses is only set by its little adjustment potmeter on the front.
So your setup will not work…
The synth speaker is glued in a solid plastic box and cannot be dismantled without breaking the box.