Make Your OP-1 Into a Toy




About: I build, I teach, I learn. Happiest when covered in saw dust, sweat and machine grease. Visit for more projects and info.

The OP-1 is a powerful synth and sampler. It’s also small and so well built that kids can safely play with it, mash the buttons, and have a blast. A favorite game among OP-1 parents is to sample kids singing, cut the sample into pieces, pitch shift it all over the keys, and have them create a cacophony of sound. The trouble is that the OP-1 is full of powerful menu and settings keys that are right next to the sound-producing keys. When you’re mashing the keys, it’s too easy to hit all the wrong ones and need help making the synth beep again, especially if you’re two.
This 3D-printed cover hides those menu and settings keys and leaves exposed the keyboard and sound-modifying keys. Mash and explore all the exposed keys, and they all either make sound or modify the sound.

The two-year-old operator shown had his longest solo session to date on the OP-1 with this cover. He has tried toy synths and kid instruments, but they don’t hold his interest. He is discerning enough to distinguish real hardware from fake, and only wants the real stuff. This cover makes that practical.

The small holes over each key allow access to the recording functions to an adult user with a paper clip or other small diameter too.

A note to those who think negatively about allowing kids to play with professional level toys:

First off, this is not my synth and not my kid (Eric and Christy lay claim to both). I designed this key cover for a friend. Secondly, it is important to treat kids as real people and exposing them to real tools at a young age is a really good way to do that. The OP-1 happens to be well-built and durable enough for kids to play with and not break anything.

Step 1: Design

I used Autodesk's Fusion 360 software to design this case for the OP-1.

The first step was to create an accurate model of the OP-1 itself. I used digital calipers to accurately measure the synth and imported those measurements into Fusion 360. The rectangular pattern tool was really helpful in creating multiple buttons of the same size and shape. I have included the OP-1 file as well as a full top cover for the synth in this Instructable for anyone who is interested in making other accessories for this powerful toy (errr... tool).

Once I had an accurate model of the device, I used the shell command to create a new body that is offset from the original by a small fraction of an inch. I cut away the areas where the buttons are that I wanted to remain open and added some clips to keep the cover latched on.

Step 2: Print

The fabrication of this key cover was done entirely by a fancy robot. I used an Objet Connex printer, but it is just small enough to fit comfortably on the MakerbotZ18 build plate (It is just slightly too big for the Replicator 2, sorry).

Step 3: Clean the Print

If you are using a resin-based printer like I did, you will need to clean the print after it is done printing. Make sure you do a thorough job cleaning, so that you don't get goo all over your expensive music toy.

Step 4: Play!

With all the recording buttons covered up the OP-1 becomes a more kid-friendly toy. Youngsters can play with all the fun buttons and not get distracted or frustrated by the less fun ones.



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    8 Discussions


    3 years ago

    This is fantastic! Would you mind if I used referenced your OP-1 model in an upcoming Instructable?(I'll give credit haha). I'm designing a rather unique case/ interface device for the OP-1!

    1 reply

    Reply 3 years ago

    No problem at all. Instructables exists for the purpose of sharing, so go forth and build. Glad you like the project. Please also share a link to what you make. I look forward to seeing it.