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Show HN: I built a synth for my daughter(bitsnpieces.dev)
285 points by random_moonwalk 5 days ago | 58 comments
fainpul an hour ago | parent | next [-]

> A 3D-printed enclosure is fine for a prototype, but a real product likely needs injection-molded parts, which require expensive tooling.

For kid-friendly toys, yes. But for older users not necessarily:

https://teenage.engineering/products/po

speedgoose 27 minutes ago | parent [-]

I have two of those. They are great additions to my drawers.

One has a silicon case and is nicer to use though.

solfox an hour ago | parent | prev | next [-]

Looks amazing! Reminds me of a funny reddit thread about a man who built a fiber optic star ceiling for his daughter. The top comment was "First child?". :)

https://www.reddit.com/r/DIY/comments/8g8pce/fiberoptic_star...

Brajeshwar an hour ago | parent | next [-]

And then the things you do to redeem your guilt for the second child is a whole interesting area.

random_moonwalk 16 minutes ago | parent [-]

That's what the drum machine module is for.

gwbas1c an hour ago | parent | prev [-]

Don't assume: Could be an only child, or the spouse is stay-at-home, or the author has family wealth and doesn't need a full time job.

prodigycorp 36 minutes ago | parent [-]

could also be the first child ;)

random_moonwalk 17 minutes ago | parent [-]

Can confirm, they're my first child

JoeDaDude 14 minutes ago | parent | prev | next [-]

Cool! Reminds of the Music From Outer Space synth in which the designer makes the claim that it "can actually get a child away from a television" and includes a video to prove it.

https://www.youtube.com/watch?v=i6M_KrZByz4

MFOS Weird Sound Generator

https://musicfromouterspace.com/index.php?CATPARTNO=WSG001&P...

afandian 20 minutes ago | parent | prev | next [-]

Amazing the things we do for our little ones. I built a toddler-friendly keyboard for my son. He's still playing some form of piano 6 years later, no longer with his fists.

https://blog.afandian.com/2019/09/ux-for-toddlers/

cjonas 15 minutes ago | parent | prev | next [-]

I've been learning CAD, 3d printing, PCB design and brushing up on my embedded programming... all with the goal of being able to build toys for/with my son. It's incredible how accessible it is in todays world, made possible by these advancements:

- incredibly powerful and cheap microprocessors (esp-32) - Fast, high precision desktop 3d printers - Affordable small batch PCB manufacturing - LLM's to advise on circuit design and help with embedded programming

Would you have any interest selling a non-comm license to the PCB, f3d files and source code? My 1.5yo son would absolutely love this!

thenthenthen 13 minutes ago | parent | prev | next [-]

Looks so nice! The sam is a midi synth chip right? Super cool. How/where did you get the knobs?

random_moonwalk 9 minutes ago | parent [-]

Thanks! Yes it's a little digital synth that receives MIDI.

I used Chroma Cap knobs: https://store.djtechtools.com/products/chroma-caps-knobs-and...

Waterluvian an hour ago | parent | prev | next [-]

If I have zero experience designing PCBs but wanted to do a similarly (non)-complex one, how much of a tall order would that be? In my completely made-up mental model, I'm guessing I just take the parts I've already breadboarded, look them up in some sidebar, and drag and drop them around, snapping to nice clean spacing, and then connect all the various pins together and have it automatically organize things? We're not going for perfect here. Just "Baby's first PCB" that at least works.

And then when I have one designed, how much would it cost to get made and sent to me if I was okay if it took a month?

But most importantly: how do I build personal confidence that I'm not shipping a potato off to be printed? Is there a community I could ask for a review from?

random_moonwalk an hour ago | parent | next [-]

Hi, your mental model is essentially correct, though it took me a good few evenings over a couple of weeks to get the workflow down in fusion 360. The electronics retailer will usually have the footprint and 3d model available on the component page. You can then import it, define which pins you want connected to each other in the footprint and in the PCB editor you can drag the routes (wires) to connect them.

Printing is way cheaper than I initially thought it would be - I paid £35 or so, including delivery and 5 of them arrived in 5 days. You can get cheaper delivery though. Also most of that cost is shipping and the setup fee - the marginal cost for each additional PCB print in the order is on the order of low single digit dollars.

Tbh my circuit was fairly simple so I just took a bit of a chance (and some extra care wiring things up). I think there’s a subreddit where people give feedback though I haven’t submitted anything.

TheJoeMan an hour ago | parent | prev | next [-]

As a hobbyist, I have had a good experience using EasyEDA [0]. It's free to use, with the caveat that you are pretty locked in to their PCB ordering service from China. However, pricing is crazy good, like <$50 total for 5 PCB's (although there will be tariffs).

Regarding your mental model, it's more like a 2-step process. First, you draw the netlist, which is the electrical circuit diagram. It's this stage you ensure there are no short-circuits, etc. Then in the second stage, you drag-drop the components to the physical layout you want. The software then has an auto-router that references the netlist and automatically generates the first pass of PCB traces. You can tweak them if you wish. The EDA software also has a rules engine that checks for correct trace spacing, vias, etc.

For a "baby's first PCB", I bet you have more skills than you realize and I would encourage you to just give it a shot. Also, if you make a small mistake, you can manually "bodge" the board by cutting wrong traces with an exacto knife and/or soldering wires to the pads.

Everything else just comes from experience! If you're staying in the sub-kHz (audio) range, you probably won't need the crazy high-frequency tricks/trace capacitance/trace-length-matching concerns.

[0] https://easyeda.com/

bluGill an hour ago | parent | prev | next [-]

Depends on complexity. The article gives a price, for 5 PCBs which isn't unreasonable. However this was a simple PCB that used a lot more physical space than it would need to (for this application most of the space was needed because of the physical space the buttons/sliders needed so it was needed so this isn't a criticism). If you want to make a small PCB much more work is needed. This was a few analog sliders and buttons - no high speed digital data, if you are designing a computer (even Apple II level complexity) it is a lot harder. If you are designing a radio there are a lot of complexity. If you want to get this FCC (whatever your local government is) certified there is a lot more complexity.

This project is something that should be easy for someone with basic CAD experience. However many projects require a lot more complexity, so don't think that because most people could figure this PCB out in a day make you think anyone can do more complex PCBs, things get complex fast.

jmb99 an hour ago | parent | prev | next [-]

If the board is small (10x10cm or less) it will be almost completely free, like single-digit dollars, through somewhere like JLPCB. So I’d say don’t worry too much about that, just jump in and try!

As for actually designing, it’s a little more complicated than that but not by much. I did my first pcbs with KiCAD ~5 years ago by pretty much just guessing and googling where things were. Completely feasible if you have 0 background experience.

drivers99 an hour ago | parent | prev [-]

jmb99 already said the part about cost/price. I just made a PCB for someone’s Halloween costume and it was only the 4th PCB I ever made. (So far I’ve used PCBWay for all 4 but since I’m in the US I also ended up doing a rush order from US-based Osh Park because I was panicking about how long the shipping was taking. Tariff situation has made shipping from China to the US more complicated. I found out DKRed, which is part of DigiKey, also makes PCBs in the US.)

For designing it I’d check out a kicad 9 tutorial playlist. You don’t need to know everything but it helps to know the right things, like how to run the design rules checker to make sure your PCB layout conforms to your schematic. There are a bunch to choose from but this one seems good: https://youtu.be/4YSZwcUSgJo

I haven’t done this but you can also try submitting your PCB design to /r/PrintedCircuitBoard subreddit for review, and they can also answer questions there.

danvoell 18 minutes ago | parent | prev | next [-]

This is awesome. Just awesome. Love that it looks like a baby toy and packs enough punch to get a kid about 20 years up the line of music understanding.

BjornW an hour ago | parent | prev | next [-]

What an awesome project. It looks fabulous!

Reminds me of the Dato Duo I have.

The "Dato Duo" is also a synth aimed at kids. It allows 2 kids to play together. it is made by a Dutch company called Dato (https://dato.mu). Their latest musical invention the "Dato Drum" had a successful Kickstarter and is shipping now. This drum machine allows even more kids to play together.

PS: As the owner of a Dato Duo I can share you a little secret: it's also fun for adults :)

tapland 26 minutes ago | parent | prev | next [-]

This is great. I’m going to start making something like this, but with some cut apple wood knobs, for my birds.

oldestofsports 13 minutes ago | parent | prev | next [-]

This is very impressive, it looks great!

tanepiper 2 hours ago | parent | prev | next [-]

I'm a 44 year old man and I would love this - for years I've tried to dabble with music with much lack of success - but this looks really fun to play with. Great job.

turbotim 27 minutes ago | parent | next [-]

I've been messing around making a small web based project that does something similar if you're interested in trying a dabble: https://shantylab.com

fainpul an hour ago | parent | prev | next [-]

There are also free software synths and DAWs available. GarageBand is the obvious one if you use macOS. I had lots of fun with that and with NanoStudio on iPad. I also own a Pocket Operator, which is fun and very mobile, but a bit pricey.

bluGill an hour ago | parent | prev | next [-]

The problem with music is you can't dabble. You need to dedicate half an hour per day for a few weeks before you reach the point where you are not terrible. You need years of dedicated practice before you can call yourself good. Finding that time is hard. Still making your own music is run and so I encourage you to press through.

0xMalotru an hour ago | parent | prev [-]

Go grab a Teenage Engineering Pocket Operator, it's definitely worth a try ! I personally recommend the PO-33 (KO!), it is fun and easy to play with :)

semi-extrinsic 3 minutes ago | parent [-]

The POs are fun to play with, but from experience I would much rather recommend getting a used mk1 Novation Circuit. For $150 - $200 you have a four track drum machine plus two tracks of a great synth engine, with a built in mixer and simple effects, midi in if you want to use a keyboard, and the thing is still compact and battery powered.

binary132 35 minutes ago | parent | prev | next [-]

Totally rad! Makes me think about what kind of simple programming could be possible with a minimal HCI like this.

habosa an hour ago | parent | prev | next [-]

This is fantastic, as a hardware synth lover and a dad you’re making me pretty jealous.

0xdada 2 hours ago | parent | prev | next [-]

Wow! Looks great and very inspiring. Great idea to make separate components that can be connected - something like a drum machine, sequencer, maybe even a chord synthesizer? It can be constrained such that you are always diatonic, you could have a mode knob too.

Jamming with other people can be a life changing experience, and to do that as a child would be a great privilege to have.

random_moonwalk an hour ago | parent [-]

Yes exactly, it would be great to be able to sync the clocks so they all ‘just work’ together. And maybe also a module that gives all the other synth parameters for the more advanced user too. I say it’s for my daughter, but I actually would love this too.

gwbas1c an hour ago | parent | prev | next [-]

Makes me wonder what the difference, in definition, is between a sequencer and a synthesizer? Is this really a synthesizer, or is it really a sequencer?

Yes, I'm splitting hairs about semantics.

strogonoff 42 minutes ago | parent | next [-]

A synthesizer is generally a higher-level ready-to-use product containing any number of oscillators, sequencers, and other circuits and bells and whistles under the hood. A device with an oscillator and a sequencer qualifies as a basic synth.

At a lower levels you find modules like sequencer, oscillator, etc. They are generally not used by themselves: you plug a sequencer into an oscillator to make use of it, just like a standalone oscillator by itself simply makes a continuous noise that gets old quickly. A synth does that connection for you and exposes the controls.

(To make things even more fun, the lines between lower-level audio modules are often blurred. For example, the difference between a sequencer and an oscillator can be best summed up as: the former is commonly designed for unipolar control rate signal change where you can specify exact level per step, while the latter is designed for bipolar audio rate signal change between two predetermined extremes—however, as the “designed for” hints, you could configure some sequencers to output a bipolar signal changing so fast it is audible, just like you could run a square wave oscillator so slowly that it becomes a 2-step sequencer.)

oidar an hour ago | parent | prev | next [-]

The linked project is both. A synth makes sounds, and a sequencer controls the sound over time usually with note on/off data. This sequencer has 4 steps before looping back to the beginning. To simplify, think of a sequencer as the music box drum and the synth as the tines in a music box.

butlike an hour ago | parent | prev | next [-]

A sequencer is always in steps. A synthesizer has a signal generator and can modulate a single step. This toy is both a synthesizer and a sequencer, but since you cannot toggle the 4 steps off, it will always be a sequencer in addition to the synthesizer

PaulDavisThe1st an hour ago | parent | prev | next [-]

The answer to your question is "yes".

It is a synthesiser AND it is a step sequencer.

dave_sid an hour ago | parent | prev [-]

Both

gulan28 an hour ago | parent | prev | next [-]

This is awesome. I had vibecoded something similar called https://chippytune.com for myself. Still working on wav support though

NickC25 an hour ago | parent | prev | next [-]

that's great! may your daughter make great use of it!

love the fact that your step sequencer even has a display to tell you what note you are adjusting to and from. i've always found that tuning synths and sequencers both analog and digital can be a pain because you can forget the note (or you don't have a good set of ears or perfect pitch) even if the result sounds good.

greasegum 2 hours ago | parent | prev | next [-]

This is an inspiring project! I would love to see more stuff like this and updates if you decide to evolve the project further.

fiatpandas 2 hours ago | parent | prev | next [-]

Regarding case material for productizing, you could consider a combination of plywood and bent sheet metal, eg like a Moog. Also check out dato.mu for a few examples of kid proof synth enclosures.

Thorrez 2 hours ago | parent [-]

Would bent sheet metal have any sharp corners or edges? For kids it's probably best to avoid those.

bluGill an hour ago | parent [-]

That depends on how much effort your spend on finish work. Files and sandpaper works wonders, but that take time. Or you can fold the edges over so that the sharp edges are on the inside (cars do this). The plywood is likely to cover all those sharp edges - plywood is easier to shape than sheet metal so this is a common cheat that can look good if done right.

dmd 2 hours ago | parent | prev | next [-]

Very cool. Reminds me of things like the Blipbox myTRACKS and the CHOMPI.

fny an hour ago | parent | prev | next [-]

Great work! This brings back memories of futzing with knobs on a boombox as a kid.

For your sake, I hope you built a heaphone jack.

random_moonwalk an hour ago | parent [-]

Thank you! Unfortunately I decided to save that feature for v2!

phplovesong an hour ago | parent | prev | next [-]

As a father to a daughter this warms my heart. Well done daddy! Points to you!

nimrody 2 hours ago | parent | prev | next [-]

It's beautiful and the demo video shows how someone with music background can make even such a limited tool sound so amazing.

bitwize 22 minutes ago | parent | prev | next [-]

The other day I came across a post on Facebook that was just some guy grousing that the new Teenage Engineering gadget looked like "a baby's activity center". And now we've come full circle: a baby's activity center that's actually not far off from Teenage Engineering kit.

eat_your_potato 2 hours ago | parent | prev | next [-]

Reminds me of the concept of the Data DUO, very inspiring

ronbenton an hour ago | parent | prev | next [-]

Wow looks professional

lovegrenoble 2 hours ago | parent | prev | next [-]

Absolutely, Kickstarter is a good idea

skrebbel 2 hours ago | parent | prev | next [-]

wow

dude250711 2 hours ago | parent | prev [-]

Another good option for a child: https://www.eltamusic.com/solar-42

On a serious note: https://www.ericasynths.lv/shop/standalone-instruments-1/bul...

eitally an hour ago | parent [-]

Perhaps more realistically, Teenage Engineering products: https://teenage.engineering/store

persedes an hour ago | parent [-]

yes, the pocket operator is a great gift for 8-9+ year olds if you're not as talented as OP :D