Adafruit NeoTrellis M4 808 Drum Machine

A while back (umm, last year?) old pal Kirby gave me an Adafruit NeoTrellis M4 with Enclosure and Buttons Kit Pack which I believe he got in an Adabox. At the time I was like, “Hey, this is neat!” and put it aside because I was busy with work. Well, I finally found it when I was cleaning the office and decided to dig a little deeper and discovered the demo code it shipped with was already running a minimal drum machine! They had some samples loaded up and it was a super-basic tracker. Fun!

The provided samples were not that great so I grabbed a kick, tom, snare, and hi-hat from the classic Roland TR-808 which, well, you probably know. As for the Adafruit NeoTrellis, it’s is a fun little drum machine! A bit challenging, and definitely minimal, but worth spending some time with. The audio is running out of the NeoTrellis and through a Bastl Dude and filmed/recorded to an iPhone.

Note: I found this guide to Trellis M4 Beat Sequencers which should prove extremely useful! It’s way more capable than I imagined, which shouldn’t be surprising since it’s from Adafruit.


Parametric Sink Strainer / Sifter

Continuing on the journey of improving my OpenSCAD skills I worked up this parametric sink strainer for the slop sink in our basement. It’s a useful print because sometimes we clean dirty things in the sink (like muddy shoes) and keeping yard waste out of the drain is probably a good idea.

Here’s the sink drain in question. I just measure the diameter and depth of the hole and created a strainer that could fit inside.

It’s not a super snug fit so it’s easy to remove the strainer by just sliding it out when not needed.

You can also make a sifter, which is something I designed and printed before when I needed to sift the rocks out of some concrete.

You can customize the diameter, height, wall and floor thickness, and size and spacing of holes. I didn’t add the capability to switch to round holes versus square holes, but that may be an improvement in the future. There’s also no lip/edge like most strainers have, so maybe that should get added to the list as well. (Or you can check out Customizable Drain Strainer by fardog.)

You can get the .scad file from – Parametric Strainer / Sifter. Just open in it OpenSCAD, set the size of things and render your object.


Fan Shelf Brackets

Once again my fan can sit on the window sill and cool my home office! We got new windows installed this year, and since it was a complete tear-out the new windows have this large lip that prevent you from placing a fan on the sill. 3D printing to the rescue!

Here’s the giant lip, which is about 6mm thick. I guess this is how they make moderns windows… I’m not sure I’m a fan. (Ha Ha.)

Here’s the giant lip, which is about 6mm thick. The bracket has a 6mm slot that fits onto the lip. The bracket also has different heights on each side of the lip to accommodate the different heights of the sill on either side.

I used 1/2″ long #4 screws to secure the brackets to a piece of 1/4″ thick Baltic Birch plywood I have lying around. (The brackets were designed with using that hardware in mind, so the lip on the bracket would be enough to prevent the 1/2″ screws from pocking through.)

Here is shelf. Good shelf. Shelf works. Shelf is removable. The only downside of the shelf is that I do not think it will support our 10 pound cat. And it definitely will not support our 20 pound cat/ Which is a shame. Obviously I’ll need to come up with a solution for those problems.

You can get the STL file from – Fan Shelf Bracket, though unless you have the same windows, it’s not going to work. Feel free to use it as inspiration to fit your own windows.


Parts Tray with Sliding Lid

I get a lot of hardware from Bolt Depot and it comes in these tiny bags with labels, which are great, but when I’m building products I find that I’m always opening and closing bags to grab what I need and I wanted to try another way. I designed a parts tray with a sliding lid to organize things a bit better.

Here’s a render showing how it fits together. I do this stuff in OpenSCAD. (I’m still far from being an expert in that application, but I am getting better, and exercises like this help.)

It’s a three piece design. There’s the bottom part (the tray) that holds things, a top part which gets attached to the bottom part with screws, and a lid. I laser cut some clear(ish) acrylic for the lid so I could see the parts inside. You could just print the tray part if you don’t need a lid.

No laser cutter? No problem! You can also just print a lid. Obviously you can’t see the contents with the 3D printed lid… though maybe if it were printed in resin? I don’t know… I don’t print with resin. Anyway, there are files to laser cut a lid and for 3D printing a lid.

Part of the idea of two separate pieces connected with fasteners was to allow for making the fit tighter or looser, to some degree. There are friction bumps on the top part that the lid slides against, and the top part flexes a bit to allow for a good sliding fit. That’s the idea anyway.

Now, the first sliding lid I laser cut didn’t fit… seems it was 2.8mm acrylic, not 3mm acrylic. To make it fit right I just added a bit of tape along the edge of the lid. (Note: Clear tape might be better. I used blue tape for this photograph so you can see it.) You can also adjust the top part and print it until you get it right. It’s a small part that doesn’t use too much filament.

I posted the in-progress photos of this on Twitter and a fellow named Pooch asked if I could just print it as a single piece standing up. Turns out you can, so I included an STL for that method as well. (I’m still a fan of printing in two pieces and then using a laser cut lid but hey, options are good!)

Because options are good I also created a “deep dish” version that’s a bit taller and will hold more (or larger) hardware a bit easier. There’s also some OpenSCAD files so you can change whatever you want. So… many… options!

You can get all of the files from – Tray with Sliding Lid.


Recording Video and (Line-in) Audio to the iPhone

I record audio & video of all my musical jams on my iPhone. I plug all my synth devices into a Bastl Dude mixer, then out to a splitter, one side goes to headphones so I can monitor, the other goes to a USB audio dongle with 1/8″ input, then into a USB to Lightning adapter plugged into the phone. It’s a little weird but it works great for me. I’ll try to describe the setup in detail below.

I’ll start by saying this. I’ve worked in media production a long time. I’ve worked on commercial video shoots, I’ve worked as a sound engineer, I subscribe to Tape Op, and I know there are a million ways to record things. This is the method I use because it’s easy for me, and a simple workflow for recording music means I can focus on actually making music and capturing it easily. Also, and this is important, I want to record audio and video together into one single file.

Not including the mixer and phone, here are the other components.

Here’s what it looks like all connected together. (Click the image for a larger version.)

Are there other ways to do this? Yes. Are some of them better? Probably. This works for me with the equipment I had on hand. I didn’t buy anything special for this because these are all components I had for other purposes or projects. Chances are if you’re already making music you have most of these things. If you’ve got an iPhone but still need the USB Audio Adapter and Lightning to USB Adapter you can get them both for under $20 USD.

For the actual recording I just use the iPhone’s built-in Camera app in video mode. It does the right thing with regards to grabbing the audio. This solution also allows for monitoring, since the audio signal splits before it goes into the phone. (Monitoring audio from the phone is… tricky.) Is it perfect? No, but it works. Audio levels are where they should be, and I don’t need to sync a separate audio file to a video file when editing the video.

I did try a bunch of other methods when I started. Including a Lightning to 3.5mm Headphone Jack Adapter, a Zoom recorder (great for audio, but no video), recording directly to a computer (video was not great) and… probably others I forgot about. Yes, I know about the Headset Buddy, and I tried a lot of different apps on the iPhone. Again, this works for me. If this is helpful to you. You’re welcome!