Adding vibrato to the Korg Littlebits

Hi all !
I would like to add vibrato, generated by a second oscillator, to the oscillator bit.
So far, I’ve tried with a mixer and split, but nothing seems to work correctly.
Has anyone a clue how to do this, so that notes are sounding correctly ?

Shame that the LFO bit is not in production yet :cry:

Hi all !
It seems a hard thing to do, adding some vibrato to the littlebits synth kit.
Well, there’s no way to connect some extra bit to the Oscillator.
So, I came up with this idea.
Assemble a LFO and some peripheral components on a breadboard and connect this between the keyboard ( or midi bit ) and the oscillator.
And whilst we’re at it, using the gate bitsnap to add a vibrato delay ( the vibrato comes slowly in when pressing a key on the keyboard ).
I don’t know for sure where to post this, so I did it here and hope that fellow LittleBit users can contribute to this.
Anyway, I made a small video about this.

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Hiya @Frankje,

Have you seen Alex’ latest invention? It’s an electro-mechanical tremolo for the Korg.

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Hi @chris101

Yes I have ! Its a cool invention !
I even created my own version of tremolo, using an optocoupler circuit, see
Optocoupler circuit :
Seashore sound waves :

Vibrato gives the sound a warmer touch by slightly detuning the oscillator by a LFO.
Unfortunately, littlebits seems to wait forever to release the LFO from the bit Lab :
Would make things a lot easier, though :yum:

I hear you about the contributed bits not moving forward. I suspect that the bitLab became too expensive and difficult to support. It seems to have all but disappeared.

Please upload a project with instructions to make your LFO device!
Then folks like me, with rudimentary electronic skills, could make your bit and add it to our own instruments.

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Maybe @sean_littleBits can answer this question please? :musical_score:

Hi Chris @chris101 and Frank @Frankje,

My electro-mechanical tremolo works as a tremolo and also as a vibrato.
When connected to the filter bit after an oscillator it changes the volume so you get a WAH WAH effect, as shown in my project mentioned above.
And when it is connected directly to the input of an oscillator it changes the tone of the oscillator instead.

I am not sure how to call this gadget then, there seems to be a lot of confusion on the internet about the real definition of these effects. Vibrato and tremolo are mixed up a lot, even by specialists knowing much more about music then i do. So I could call it a vibrolo. Ha. :joy_cat:

Making a real LFO would be nice, it is a great addition to the KORG Littlebits set.

What a great idea Alex !
Since LittleBits is known as an open source project, it would be neat If we could make our own LFO bit.
And oh Alex, since vibrato modulates the tuning of the oscillator, care must be taken that this modulated tuning still follows the notes of the tone scale.
If not, it would be musically a misfit :rofl:
As such, I’d love to continue in the spirit of the synthkit and relie on analogue circuitry.
If you like, I could provide a PCB layout for smd components, so that everyone can make their very own LFO bit.
So, the circuit I designed could be improved somewhat to suit some needs.
What do you like to see implemented ?
For now, the circuit uses only a pure sine wave, which modulates the control voltage coming from a keyboard or midi bit.
I have used a precise opamp to accurately follow the control voltage.


@Frankje what chip are you using?

I tried making an smd Bit with a pcb etched at home. I found the process challenging, but Im open to trying it again. Maybe you can share some tips & tricks with us?

One challenge was soldering grey Bitsnaps to the board. How would you approach that problem?

Hi @JackANDJude
I must check my design for the right chip number, but I’m confident it exist also in smd.
For the grey bitsnaps, I think we should use the eagle files of littlebits since the pcb design is fairly easy to adapt our project.
For prototyping bits, I use a small drill for the female bits, since their contacts don’t align the standard pin width.

Hi –

Glad to see the usual suspects on the job! :grinning:

I drew some inspiration from the Velleman MK-105 signal generator kit. It is a 555 timer followed by a two stage passive filter and an NPN transistor wave shaping stage. The passive filter converts the 555’s square wave into a triangle wave and the transistor stage shapes the triangle into a sine wave. The signal generator is tuned for 1KHz – too high for an LFO.

However, the littleBits i16 Pulse module a good starting point. It’s 555-based and the frequency sweeps from sub-audio into the lower audio range. A two stage passive filter tuned to 7Hz (R 100K, C 0.22uF) produced an interesting result. I haven’t been able to get the transistor wave shaper to work (yet). A Dimmer or Mixer acts as a level control and sets the depth. The build is on a solderless breadboard and hooks in through a Proto module.

This project has driven my spouse crazy! (Not the interesting result mentioned above.) :smile:

All the best – pj

Hello @pjd and @JackANDJude and @alexpikkert !
For the seashore soundwave project, I’ve created a LFO circuit around littlebits. As PhD mentioned, the pulse bit is a good start point for creating a slow LFO. Follow this by a timeout bit, you can create a long on, short off pulse. Then connect this to a envelope bit and voilà, you have a LFO.
With the attack and release controls, you can create a triangle, sawtooth or anything in between.
A pure sine wave is hard to achieve, so for the vibrato I’ve used a so called phase shift oscillator.
But maybe there are better ways ?
Included here a schematic diagram and fritzing layout, enjoy :yum:


Perfect! Thank you @Frankje.