Buzzing sound in the background

@frankje I think it would be cool if you uploaded this to and link to @pjd 's original post in your description. While you’re at it, perhaps you’d like to change up the code to use react to input Bits?

Hello @JackANDJude,
Well, right now I’m working on this project to add fresh sounds and drum loops. I might as well add a few more functions in the sketch.
When completed, I will upload this to littlebits inventions with permission of @pjd. He was so kind to share his Project as open source.
I will do my best :blush:


Hi @Frankje @pjd @JackANDJude,

great alternative BeatBox, this Mini Pops !
I built this little machine and found two really funny things:

It worked without the extra voltage drop bit. Huh? …
I checked with my multimeter and it worked on 5.05 Volt.
How to explain…

The new pulse output for an additional sequencer on D1 did not work in the beginning, I added my oscilloscope and saw very small pulses. So I added a little delay in the ino program (2 msec for the gatePin) and voila, the sequencer started… Use 10 msec and you get a different sound)
As a consequence the maximum beats per second dropped, but you can’t have everything… :joy:

See the result here, with a sequecer and a micro sequencer with in total 4 different sound combinations:

(4 out of a zillion possible sounds !) :musical_score: :musical_score: :musical_score: :musical_score:
Great !


Hi @alexpikkert

Cool, dude!

WRT your second observation, I suspect that the sequencer as some timing requirement on its gate signal. I can’t remember if I passed this suggestion to the littleBits folks, but it would be great if they published the timing requirements for the gate signal. This bit of info would eliminate a certain amount of trial and error. It would also help to publish a set of requirements and guidelines for using the Arduino buffered outputs (D5 and D9) with everyday digital circuits. The OP AMP slew rate affects timing when driving CMOS logic.

All the best – pj

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hi @alexpikkert and @pjd and @JackANDJude !
Thank you Alex for taking time to study the mini pops project and for finding a solution to the delay of the sequencer pulses : you’re the best ! :clap:
I’ve given it even more time (30) and also adapted the tempo control,so that the extra delay for the pulses, are compensated.
Could you give it another try ?
In the meantime doing so, I programmed 4 new extra patterns and these can be controlled by the dimmer at a1.
I’ve uploaded a new ino file with the updated sketch to the MiniPops project. It’s best that you download ALL files ( including kits, patterns and waveforms and minipops.ino).
Unlucky for me, 5V to the arduino gives buzzzzzzz., so I really need the 4.6V adapter and opto circuit :open_mouth:
Tomorrow, I will create a optocoupler bit with the HDK.
Many greetings


version 3 with 8 rhythms and better sequencer trigger output on D1
:musical_score: :grinning:


3 posts were split to a new topic: Cardboard Sequencer & Noisemakers

Hi Frank @Frankje
Can you maybe rewrite the beatbox pops ino program for an arduino UNO or NANO?
It seems to work only for the Littlebits W6 Leonardo version… :grinning:
I got this question on my Youtube channel…

Hello @alexpikkert
Its best to ask pjd to transfer the code to Arduino Uno.
He has developed the program so he will certainly know how to do this properly.
I just created new sound samples and patterns for the drum loops.
Wish you the best,

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Thanks Frank,
I will try.

@alexpikkert I think @pjd mirror posted all his littleBits projects on his site. Maybe check here to see if he originally wrote it for Uno?

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I can’t tell exactly how to set this up with the proto-bit. Can you give more instructions? Thanks

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Did I make a mistake? I still get the same buzz but at just a tad different frequency. Output say 4.59v

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Hi @brohoho
Your protobit circuit seems good for powering your bits.
Did you also use the filter bit (as described in the project) ?

I’ve tried it this morning and it sounds fine. Can you upload a sound snippet ?

This is the link to the original MiniPops arduino file. Maybe you have a bad sketch ?


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I downloaded your sketch and get the same buzz. I will try to make the filter on a proto bit. I don’t have the perf board or ends to do like you did. It may take me a bit of trial and error to get it. I’m not great at reading schematics nor understanding exactly how the proto bit is setup.

Hi @brohoho,
This is how the protobit works:
The input side ( +5Volt, GND and data) is connected to the lower screw connector
The output side(+5 Volt, GND and data) is connected to the upper screw connector.
When the three black connector pieces (1,2,and3) are in place, the input side is directly connected to the output side,
If they are removed, the input side and the output side are disconnected from each other.
This gives a lot of possibilities to connect several things in a littlebits project.
Hope this helps to undestand how the protobit works, :grinning:


Hi @brohoho and @alexpikkert
thank you Alex for this great drawing, I always had to look how the connections are made :grinning:

So, for the circuit :
If you’re not familiar with perfboard, you can always wire the filter circuit to a littlebits Proto Bit.
Here’s a picture of how this can acomplished.

Don’t forget to put 2 jumpers on positions 1 and 3 (left and right, center is open)

This should also work.


You guys are awesome. Thanks for the help. Completed and working. Buzz is gone.


Hi @brohoho @alexpikkert @JackANDJude

You’re welcome ! This is what this forum and Littlebits are all about, helping wherever we can :grinning:

I hope you’re enjoying the MiniPops project :grinning:

Which brings me to a question :
I’ve seen my inventions back in my profile (YippeeYaYee). However, when I looked at my MiniPops project, the arduino files were not correct. When I edit them in the inventions editor, it seems I cannot add these back again (only image files).
I solved this by adding a link to my dropbox. But is this the way it should be done ?
My other inventions (string synthesizer) suffer from the same problem.
You can download these files, but they are not working in arduino IDE.


Can someone try this also with mine or their files ?


Hi @brohoho,
Great to see it is ok now !
Just curious, does it work now also without the first voltage-drop filter, the one directly after the powe bit ?