Creten Bluetooth Speaker Project

Purpose

This is a fun project inspired by [DIY Perks] (https://www.youtube.com/@DIYPerks) on YouTube. Instead of using carpentry, I elected to draw the project in CAD and 3D print the concrete form and most of the components. I used PLA for the form and a high durometer TPU for speaker components. I also modified his design using a square port on the top to mount controls and other items vs his elongated port. This change allows the concrete to flow into the space below the port more easily so that less water is required in the concrete mix which makes the housing stronger once cured.

This has been a fun hobby project and I hope sharing these 3D print STL files will allow other hobbyists to experiment and try out the appoach.

![[CretenBLE.png]]

Instructions

The included STL models were created with Fusion360 using the free maker edition. The parts were all printed on a printer with 300mm x 300mm bed.

The form built in halves, both to allow the final product to be larger than the printer bed allows as well as to make it so the form can be removed from the housing once the concrete has cured. ![[CretenHousing.png]] The Bottom Plate models are the first to print with the inner and outer shells mounting to the Bottom plates. They all have a tongue and groove design that keeps everything from deforming with the weight of the concrete and also prevents the concrete from leaking, if you use vibration to remove air bubble from the mix.

The Pins hold all of the forms together and allow the form to be dissassembled once the concreete cures.

The Speaker mount, Speaker Rings, Control Panel and USB plug are all printed from TPU. 3" Dayton Audio speakers were purchased from Dayton Audio and 50W BLE amplifier board purchased on Amazon.

Finishing

After the concrete cured I cleaned up the housing by sanding it with 80grit sand paper with a water slurry. This cleaned up the edges and exposed the aggregate on the surfaces. The Speaker mount assembly is a press fit. There is a speaker mount pattern that I used to cut out a thin piece of plywood that give the front an warm accent and hides the speaker fasteners. The Speaker mount and speaker rings have a lip in the design that holds the wood insert. Installing the wood insert is tight and requires a technique similar to mounting a tire on a rim.

I used USB-C type charge port interface in the printed grommet. This was connected to a Battery Management PCB board for a 3S or 4S configuration that is wired to an on/off switch and mattery level indicator. There is a momentary switch type button in the battery level indicator circuit that power the level indicator when pressed. I used Lithium Ion 13650 batteries from disassembled old laptop batteries. in a 3 battery configuration it gives me 8 hours of runtime.

I know the instructions are sparse, but its a hobby project you should modify the materials to your own design and have fun figuring it out.