Introduction: Pocket Amp! Near-Universal Clip-on Amplifier for Smartphones

About: Hi I'm Michael! I love all things Science, Engineering, & 3D Printing. If you've enjoyed my work then I've love to hear from you!

This device is a clip-on passive sound amplifier for your smartphone!

*If works by redirecting the sound from the side of your phone to the front. Its hollow and linearly expanding geometry amplifies the volume for the user while reducing undesired noise emitted in other directions.

*It is nearly universal in that it fits any smartphone with a SIDE speaker. Please see reference image for acceptable speaker locations.

*It also has a key chain loop so you can keep it handy.

*We deigned this device so we could distract our child with a phone in public spaces without bothering other people. It lets our daughter engage with a phone & actually hear it in a crowded restaurant. We prefer this to headphones because she can still remain engaged with us and we can ensure that she is not damaging her hearing.

Video demo with sound. (Note we added the knob to the screw after filming so you can do it by hand without the screwdriver.)

Step 1: 3D Printing Settings

This design is very forgiving, stl file attached to this step. (Please note and respect sharing license thanks!.)

*Material- Any 'hard' material acceptable. (PLA, PETG, ABS, etc)

*0.2mm layers have been proven to work. Finer would be OK. After printing, cut off the large support disc on the bottom around the perimeter. (It is there to aid in bed adhesion during printing.)

The job takes about 2 hrs, and costs about $0.33 in PLA. Good candidate for an end-of-spool-job.


This device requires one non-printed part. 1x: Phillips Rounded Head Thread-Forming Screws for Plastic, Zinc-Plated Steel, Number 4 Size, 5/8" Long

Press the screw into the nut and superglue the head in place to make them into one permanent piece. Then screw it into the amp as shown.

----The design intent of the screw is to push on one side of the 'tongue' so the screw never directly contacts your screen which would damage it, also the flexibility of the tongue can provide some compliance to maintain the clamp without hurting your phone. (There is are surprisingly vast differences in phone thicknesses out there!) Still, don't over-tighten it.

-Note this device will not fit around bulky phone cases. If you want to try to make it work on top of a thick phone case you 'might' be able to warm it with a hair dryer for a few seconds to soften it enough to open the bracket more.

That's all there is to it, this is an easy project. Enjoy!

Audio Challenge 2020

Participated in the
Audio Challenge 2020