Introduction: Concrete Volume Knob With LED

A wooden speaker needs some nice volume, bass, medium and tremble knobs, but on the market I could not find something that I would use, so without any further thinking I thought to Make Them !

Step 1: Experimenting

I found Concrete quite hard to make slick small objects so a lot of experimenting was done. These are the first knobs produced, but they were not as good as they can be.

I even covered some knobs with White Glue and that gave a glossy finish to them, however it does not look well done.

Step 2: Final Mold

After some trials the final mold was decided as on the image. It is a piece of PVC tube with a cut to take out dried concrete easily and a tape attached to the bottom so it stays inside the tube. A thick metal wire was added so the knob can spin the volume potentiometer.

Step 3: Adding LEDs

It was supposed, that each knob will have some warm ambient lighting and this was achieved by adding a flat LED to the knob right next to the wire in the middle.

Step 4: Epoxy Fails

Failure is a good lesson, it turns out epoxy resin in not a very dense liquid (when it is ready to apply), and what happened is that it just went down through the space between the PVC tube and the concrete knob so there was nothing left to cover the LED. The idea was to create a small bath with LED, then pour epoxy resin to that bath and let it dry, fixing the LED in place and adding rigidity to the metal support.

Step 5: Pre Final Knob

The next method worked and this is how the knob looks like. I also added a bit of flower to the Epoxy resin so it is translucent, not transparent. You can see the difference between the small knob and the big knob lit.

Small knob has only Epoxy Resin

Big knob has Epoxy Resin mixed with flower.

Step 6: Pre Final Look

As the whole process took a lot of time and patience, I was very excited to attach the knobs to the speaker and they WORK !

However, I am not satisfied with:

- Knobs are not aligned (To place the support exactly in the middle is a challenging process, if you have any suggestions on how to achieve it please let me know).

- The light is not spread equally. This is because of different thickness of the epoxy resin layer I guess, and because the LED is not in the middle.


Step 7: Next Steps

The next steps to fix all the bugs are:

- Find a way to put the support exactly in the middle

- Each knob should have more than one LED so the light spreads equally.

Epoxy Speed Challenge

Participated in the
Epoxy Speed Challenge