Orbital Sound 2




Introduction: Orbital Sound 2

Having created a previous project called Orbital Sound, the thought came to mind as to whether I could bring it more up to date and include lighting in addition to sound. This would entail electronics and some form of sensor and control.

The solution presented itself in the form of a Circuit Playground* microcontroller.

This ticked a number of boxes for preinstalled elements, sounder, Neopixels (arranged in a circular pattern), and accelerometer with a small footprint and bolt compatible electrical connections which would come in handy as part of the assembly. Battery operation also being a bonus.

The original version was a fixed form whereas this updated version would enable different sounds and lighting schemes to be employed enabling many variations.

All this would be encapsulated within a 3D printed body.

*The author has no affilation with the CPE/CPB, its creators, manufacturers or suppliers.


Circuit Playground Bluefruit

Battery LiPo 3.7V/500mA

MakeCode Maker

Filament PETG Transparent/Clear - Main Body

Filament PETG Transluscent Green - Cord Fixtures

Slicer Cura or similar application

Bolts M2.5/30mm + nuts - Qty 4

Paracord 140cm length, 1.18mm diameter

No affiliation to any of the suppliers used in this project, feel free to use your preferred suppliers and substitute the elements were appropriate to your own preference or subject to supply.


3D Printer


Screwdriver (to suit bolt head pattern)

Soldering iron/Hot plate

Sanding Paper

Needle Files

3mm Drill Bit


Know your tools and follow the recommended operational procedures and be sure to wear the appropriate PPE.

Step 1: Design

The spinner was designed using BlocksCAD as a 4 part assembly.

The aim being to keep the size similar to the original Orbital Sound for stability and ease of use.

The body consisting of 2 parts, housing the battery in one half and the microcontroller in the other half.

Light transmissible filament is used to enable the Neopixel lighting effects to be seen.

Openings are placed to enable access to the USB and battery connectors.

This means that coding updates and testing via USB and battery charging can be applied without dismantling.

The reset and buttons A & B are accessible.

Additionally, holes in the body align with the bolt through connection points on the microcontroller which are also utilised with bolts to clamp the halves together. The two halves fit together forming a cylindrical encapsulation.

The cord supports consisting of 2 identical elements which fit on the outer side of each body half.

These are separate elements due to the inability to loop a single cord through the central body of the spinner and as such needs to be robust to withstand the pulling forces applied during normal use.

The cord supports also contain bolt alignment holes, enabling the body and cord supports to be clamped together.

Four bolts which pass through both the supports and body are used to clamp everything together.

Step 2: Slicing

Cura was used for the slicing process.

For maximum strength the Infill was set to 100% for all elements.

Base adhesion: Brim

No supports are required.

The total number of elements consisting of a battery compartment, microcontroller compartment, two buttons and two cord supports.

Subject to the size of your printer bed and any colour options, elements can be grouped togther to reduce print runs.

Total print time: 12 hrs 30 mins (In my experience Cura over estimates the print time, therefore consider this worst case)

Step 3: Post Processing

Post processing may be required subject to the quality of the printing.

Remove any rough or sharp edges with sanding paper or a file from the outer edge of the body halves.

Stringers may exist in the holes which can be cleared out with a drill bit or round needle file.

Ensure the domed holes in the cord support are clear and smooth to reduce the likelyhood of cord fraying due to rough surfaces.

The button extenders may require a little sanding on the base to adjust the height to ensure the CPB buttons are not depressed when the two halves of the main body are clamped together.

Step 4: Attach Cords

Using a 70cm length of 1.18mm cord per side.

Having tried a number of different types of cord/ string etc. twisted packing string starts to loose its twist and flat film raffia starts to fray, paracord has shown better long term performance in use.

Additionally of the varieties tested thinner cord (allowing more twists), performed better than thicker cord.

Thread one end of the cord through one of the domed holes and tie a couple of secure knots close together, repeat for the other end of the cord to form a loop.

Pull the cords through the holes until they stop in the underside of the domes and pull tightly.

With a soldering iron, flame or hot plate lightly melt the top of the knot and whilst still molten press it on a cooler flat surface, repeat for the other knot. This process may need to be repeated a number of times until the knot is flatterned to the same level as the cord support. This is so that the cord support lays flat against the main body of the spinner when screwed together.

Repeat the process for the other cord support.

Step 5: Assembly

Fit one of the four M2.5 bolts into each corner of one of the cord supports and align the smaller outer crescents with the connector openings in the battery compartment.

Place the battery compartment with the cavity uppermost over the bolts.

Insert the battery into the battery compartment with the battery plug aligned with one of the two exit slots with 20mm of free wire extending beyond the body.

Ensure any excess wire is folded along the side of the battery rather than underneath.

Wire under the battery will prevent the two halves clamping together neatly.

Place the microcontroller (facing upright, buttons visible), over the battery this should fit into the circular recess in the battery compartment with the battery socket in line with the battery plug. The bolt through holes in the microcontroller should align with the holes in the body half.

Fit the two button extenders into the holes in the microcontroller compartment.

Fit the microcontroller compartment over the microconroller aligning the '+' symbol with the power plug and the 'U' with the USB connector. This ensures the buttons align with the holes in the body.

Ensure the button extenders do not fall out.

Place the second cord support over the four bolts ensuring the centre hole in the cord support aligns with the hole in the main body.

Over the bolts fit the nuts (add threadllock or use self locking nuts) and tighten.

Check to make sure that everything is secure by first pulling on each cord in turn and then together in opposing directions as would be the case in use.

The assembled size is 68 mm diameter x 31 mm thick and weight of 80 gr

Step 6: Software

The application code is created using MakeCode Make Blocks.

Utilising the accelerometer to assess direction of rotation and magnitude which is then used to control the ring of Neopixels.

Two functions are used which follow the same basic methodology.

Forward - Increases the tone frequency and increments through each Neopixel in turn.

Reverse - Reduces the tone frequency and decrements through each Neopixel in turn.

All encapsulated within a forever loop.

External control is facilitated with buttons A & B

Button A, allows one of 10 single colours to be selected on each button press.

Button B, selects between single colour and random colour mode.

Pressing Buttons A & B together switches the sound on and off.

If required the reset button is accessible via a hole into which a probe can be inserted.

Step 7: Operation

Ensure the battery is charged prior to use either prior to assembly or in situ.

Connect the battery to the microcontroller.

Button A, allows a different single colour to be selected on each button press.

Button B, selects between single colour and random colour mode.

Pressing Buttons A & B together switches the sound on and off.

The reset button is accessible via a hole into which a probe can be inserted.

Before use and periodically during use check that the spinner has no issues and that the string is not fraying.

If any issue are found better to re-thread with a new string.

As a precaution wear eye protection in case there is a failure of the spinner or the string should snap.

Without handles:

Stretch out the string loop to form two parallel lines with index and middle fingers of each hand looped through the turns at the extremes

Clasp the string in closed fingers.

With handles.

Stretch out the string loop to form two parallel lines clasp the handles in closed fingers.

The rest of the process is applicable to either method.

The spinner will be self centred if the strings have been fitted to form the same length and/or equal lengths held in the hands.

Hold the string loosely with forearms parallel such that the spinner and string form a "V" shape with the spinner at the bottom of the "V".

The string is tensioned by rotating both hands in unison (creating small arcs), maintaining the "V" shape (as far as possible); as the string tightens it should shorten as it is wound.

Once the string starts to produce kinks, it is wound sufficiently.

At this stage maintaining parallel forearms pull your hands outward away from each other.

The spinner will start to spin unwinding the twist previously applied.

At the same time sound will be emitted with the tone changing in frequency, increasing rotating forward and reducing rotating backwards.

The Neopixels following a similar process but with light.

Once unwound the momentum will cause the string to wind its self in the opposite direction but at the same time losing momentum and slowing down.

During this stage relax the opposing pull between your hand and pull them apart again causing the spinner to rotate in the opposite direction picking up speed in the process.

Repeating the process with a smooth co-ordinated action will keep the spinner rotating with light and sound.

It may take a little practice to get the spinner to rotate.

It's also a good exercise for your arms, in fact more so than the original design due to the increased mass which requires more force to maintain the rotation.

Step 8: Finally

There we have it, all done for now.

Time to give it a whirl or a spin either way have fun.

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    3 months ago

    Looks good but I'd like to see and hear a video of the spinner in action!


    Reply 3 months ago

    See Step 7 were a video file has been included :)


    Reply 3 months ago

    Thanks...I was looking for a 'play' button, the mp4 is not obvious so assumed the download for the file was part of the build.


    Reply 3 months ago

    Thanks :)