If you’ve ever had to work on a project that needed capturing high fidelity audio, you may have come across the ever so popular H4N audio recorder. For an upcoming project, I needed to use the handy device as a boom mic.

I have an on-stage mic stand that works great but mine only came with a typical slide-style mic adapter. I hacked up this bit a while ago but it’s got a broken part and we can make something better. Out of the box, the H4N doesn’t include an adapter for mounting it to a mic stand.

Mic stand Adapters online go for around $10-20(plus shipping), but we can design and 3D print a custom one for about $2.50(in material) using free 3D cad software like Autodesk 123D Design.

Using a on-stage mic stand with the H4N makes a perfect combination for a boom-mic.

Download available on Thingiverse

Because of the ridges between the layers of a 3d printed part, the threads get etched into the cavity of the adapter. The tolerances hold up nicely with a diameter of 14mm printed with 2 shells, 10% infill, 0.2 layer height and 90/150 speeds. The most common mic stand has a metal rod with a threaded tip that has a diameter of 13.5mm.

To secure the connector and attachment pieces together, we’ll need a metal screws with plastic knobs and a screw nut. This simple 2-piece design secures the H4N to the on-stage mic stand rather nicely. Notice the cavity is almost too big to hold the screw nut. This can easily be corrected by adjusting the sketch ~0.3mm smaller.

The connector and attachment pieces have these tiny ridges on the surface where the two parts connect; causing friction when tightened and locked into position. I got this idea from an camera lighting mount that has a similar swivel type mount. Notice how some of the ridges are scuffed up. This is from the ridges smashing into each other from the initial installation. The may wear down over time, but I don’t plan on moving it that much.

It’s very convenient when audio/video devices use standard mounting holes, common among tripods and the H4N has one in the back of the device. The screw has a plastic knob and a standard tripod thread. The knob secures the attachment part to the H4N by fastening through the mounting hole of the attachment piece. It was actually scrapped from the very camera light which gave me the idea for the ridges in the adapter. Since the length of screw was too big, I used a cylinder to create spacer that would keep the pieces tight when fastened together.

The two piece design allows for tilting the H4N in different positions. The knob is loosened and tightened to adjust the position. The screw nut keeps the connector and attachment parts secured when the knob is tightened. The screw nut itself is held inside a cavity on the outside of the adapter.

Designing Parts for 3D Printing

Here are a few simple tips to consider of when designing parts in Autodesk 123D Design.

• Sketches can be drawn directly on a surface (not just the grid) and can be used to subtract selections from objects.
• Creating support structures can be used to add stability to parts making them stronger against stress, tension and weight.
• Support structures like ‘pillars’ or ‘beams’ can also be used to prevent overhanging issues while printing.
• Chamfering edges for parts that extended out 90 degrees also prevent overhanging issues during printing.

Making Circular Patterns with objects

I used the circular pattern function to create the 20 solids that up make-up the ridges in the swivel connector. Instead of painstakingly copying, pasting, and rotating each solid, we can dynamically create an array of objects with the pattern function. Here’s a quick break down on each step.

• Select the object you want to repeat. You may also select multiple objects.
• Select Pattern > Circular Pattern
• Change the selection to Axis and highlight the outline
• Enter a number count and enter to confirm

I really enjoy designing parts for these types of projects because it like designing a fix to a problem. Creating parts that connect things together is a great way to gain experience in industrial design. Personally, it’s very fulfilling and rewarding. I hope this weeks Layer by Layer tutorial gives you an insight on how you can use a free piece of cad software like 123D Design to make a professional quality adapter. Thanks for reading, and until next time – learn, make, share repeat.

Every Thursday is #3dthursday here at Adafruit! The DIY 3D printing community has passion and dedication for making solid objects from digital models. Recently, we have noticed electronics projects integrated with 3D printed enclosures, brackets, and sculptures, so each Thursday we celebrate and highlight these bold pioneers!

Have you considered building a 3D project around an Arduino or other microcontroller? How about printing a bracket to mount your Raspberry Pi to the back of your HD monitor? And don’t forget the countless LED projects that are possible when you are modeling your projects in 3D!

The Adafruit Learning System has dozens of great tools to get you well on your way to creating incredible works of engineering, interactive art, and design with your 3D printer! If you’ve made a cool project that combines 3D printing and electronics, be sure to let us know, and we’ll feature it here!