Rondo started with a broken music box.
Ines found it at a flea market in Lisbon: a tin box the size of a matchbox that played one waltz, with three notes missing. Theo offered to fix it and got slightly carried away.
A music box plays one loop, forever.
Inside the tin was a brass cylinder studded with pins, turning under a steel comb. Each pin plucks one tooth, and one turn of the cylinder is the whole song, played the same way every time since about 1950. That is the charm of a music box. It is also its limit.
So we asked a slightly silly question on the back of a receipt. What if there were four cylinders instead of one, each a different length, so they drifted apart and fell back together like planets? And what if you could move the pins yourself?
Four loops that never quite agree, and pins you place with a fingertip. That was the whole idea.
There was a second reason, harder to say out loud. Almost everything we owned came with an app, an account and a quiet countdown to its own retirement. We wanted to make one object that would still be on the shelf in 2037: still working, still worth picking up, needing nobody’s permission.
We called it Rondo, after the musical form in which the main tune keeps coming back, a little different each time.
From cereal box to sapphire.
Four years and a lot of prototypes, most of them built on one kitchen table. Tap any of them to hear what it could play.
2023Cardboard rings and a phone
Four rings cut from a cereal box, spinning on a lazy Susan, with a phone underneath reading them through its camera. It managed one drum ring and one melody, and it crashed every four minutes. We played it until two in the morning anyway.
2024Printed prototype no. 7
Numbers one to six were too big, too loud or too fragile. Number seven was printed in orange, turned on skateboard bearings and glowed through frosted tape. It had three rings of different lengths, and for the first time the loop drifted on its own. Nobody wanted to put it down.
2025The first aluminium
Fifty bodies turned from solid aluminium for our engineering validation test, EVT for short. The rings finally clicked like a watch bezel, Glow arrived to play chords, and we found one hundred and twelve things to fix. We fixed them.
2026Into production
Anodised in four colours, then carried everywhere for a year: kitchens, night buses and one very long flight. Every trip sent a list back to the bench, and it was retuned more times than we can count. Its loop is Morning Orbit, the one we open every demo with.
Ships spring 2027.
Two hundred and thirty‑eight grams.
That’s all of it. Here is where every gram goes, and what making it costs, as plainly as we can put it.
| Part | Share of the weight | Weight |
|---|---|---|
| Aluminium body and four ringsAt least 70% recycled | 152 g | |
| Battery, 2,400 mAhOn a connector, not glue | 42 g | |
| Circuit board, chips and 384 LEDs | 17 g | |
| Speaker and passive radiator | 12 g | |
| Steel bearings, magnets and screws | 7 g | |
| Frosted glass light rings | 6 g | |
| Sapphire sun | 2 g | |
| Rondo, in total | 238 g |
Mostly recycled aluminium.
At least 70% of the aluminium has been used before, and every offcut from turning the body goes straight back to be melted down. We want 100% for the second batch. If we miss, we’ll say so here.
Paper, not plastic.
Rondo travels in a moulded paper-pulp tray and a card sleeve printed in one ink. No plastic bags, no foam, no twist ties. Even the cable is held with a paper band.
Boats, not planes.
Stock crosses oceans by sea and finishes the trip by road. It’s slower, so we simply plan further ahead.
About 9 kg of CO2e each.
Our estimate for one Rondo, from the mine to your door. Nobody independent has checked it yet. When they have, the full report goes on this page, even if the number goes up.
A way home.
When you’re finished with it, send it back at our cost. We’ll reuse what we can and recover the aluminium and the battery. Better still, give it to someone.
The ten‑year promise.
Six promises, and exactly how we keep each one. They’re printed on your receipt as well, signed by both of us.
- No subscription. Ever.
You pay once. Every sound, every feature and every update is in that price. There’s no server behind Rondo, so there’s nothing to renew and no bill to pass on to you.
- No account, no app, no cloud.
Rondo does all its thinking on the device. A loop travels as a link with the whole song written into it, so sharing needs no server and will still work in 2037. It connects through standard ports that will outlive all of us: USB-C, 3.5 mm TRS MIDI in and out, and Bluetooth MIDI.
- Open firmware.
Rondo OS is published under the MIT licence on the day we ship. Its complete source, build tools and signing keys are also held in escrow by an independent solicitor, to be released to everyone if we ever stop trading.
- Made to be opened.
Four T5 screws hold the base on. Behind it sits a 2,400 mAh battery on a connector, not glue, that you can swap in five minutes. We stock every part until 2037, sell them at cost, and publish a free repair guide for each one.
- Updates until 2037.
Written on your receipt. An update is a plain file you install over USB-C, with no account involved, and none of them will ever take away a feature you already have.
- Five years of cover.
If anything stops working as it should in the first 5 years, a tired battery included, we repair or replace it for free. And you get 100 nights to decide whether it stays.
Ines & Theo
Two people and a kitchen table.
Ines
Industrial designer
Ines spent ten years designing things that were thrown away after two. She draws every part at full size on paper before it goes near a computer, and she chose each radius on Rondo by carrying it in her pocket for a week.
- Favourite loop
- Snow Day · open it in Rondo Web
- Favourite finish
- Moon, for the tool marks
Theo
Sound engineer
Theo writes the software that turns numbers into sound. He built all five of Rondo’s voices from scratch, and the clock that keeps four rings in time to the millisecond. He has tested every firmware build with the same loop, which has been playing on his desk since 2023.
- Favourite loop
- Kettle · open it in Rondo Web
- Favourite finish
- Eclipse, because he works late
See youin 2037.
That’s the plan: one small instrument, a long time, no strings attached. Try it in your browser first. It’s the same instrument, minus the aluminium.
- 100-night trial
- 5-year warranty
- No subscription, ever
P.S. Ines still has the music box. It still skips.