I was going to say that $200 seemed awfully expensive for a programmable kitchen timer.

I've had a project idea for a while that would require a bit more juice. In short, I want to make a music practice timer for ADHD kids that avoid actually playing music during practice time. I want it to be beefy enough to run some simple ML for detecting instruments being played, and I only want the timer to count down while the instruments are playing. I picture it looking a lot like the clock above, but with something like a Raspberry Pi jammed inside so it's got enough power to reliably detect "violin."

Any ideas on hardware for that?

"Identifying Different Musical Instrument Sounds Using Fourier Analysis in LabVIEW" Rather than "ML" du jour, I would say that a fast Fourier transform would get you sufficient data to determine if practicing or talking or silence.

Definitely valid callout. I was also looking for an excuse to play with audio ML, but you're totally right that just examining a Fourier series could very likely do a great job of determining whether a given type of instrument is being played.

Which an FFT on an ESP32-S3 with it's Xtensa LX7 vector extensions can be quite fast

https://www.reddit.com/r/arduino/comments/16asjx9/esp32s3_do...

The actual github : https://github.com/stolk/little_kiss_fft

The adversarial child would be playing recordings into the timer within minutes no?

I'm assuming the child is question is not so much adversarial so much as ADHD. They'll be actively looking to divert their attention to more stimulating activities than playing an instrument but not attempting to cheat the system. And I'm assuming a parent is present but not necessarily in full control of the child. Or it could work equally well for an adult in a similar situation.

For the non-adversary who wants something similar in nature, that might help them practice, why not? Not everyone is trying to cheat.

The ESP32S(1?) that's inside is fairly powerful as embedded mcus go but that said...

If you need grunt and you don't specifically want the aesthetic of an led matrix panel you'd probably be better off with an old phone or tablet based thing.

The TC001 afaik doesn't have any mics inside anyway.

Hate to burst your bubble, but as an amateur musician I fear this would backfire, or at least fail to result in any improvement in playing ability. Silence and time are absolutely critical to playing music. By analogy, measuring 'time spent drawing bow across strings' would be as useful to a violin student as 'time spent pressing foot on accelerator' would be to a driving student!

From my own experience learning to play the organ, I have improved least when I play relatively fluidly, practising with music well within my abilities. On the contrary, the most improvement has come when I've slowed down, allowed myself to count the timing, repeat sections, read the sheet music more carefully or even just take a break entirely. So although silence won't improve one's playing by itself, I think it's a natural by-product of an effective studying technique that, if at all possible, shouldn't be discouraged with such a timer.

There could be an allowance for time spent not playing music. Keep the timer going for a few minutes after the music has stopped. Require a minimum ratio of music playing time to overall time. So, after a lengthy silence, only playing music will advance the timer.

But, yeah, it may or may not be helpful.

It's a great point. For a contemplative learner deeply focused on what they're doing, this is definitely a bad idea. I'm aiming at sort of the opposite kind of learner.

i'm building a low volume product. if you add the cost unfortunately you will see it's impossible to do something of good quality and low volume with much lower price.

you don't only add the sum of the electronic parts, but materials, r&d, payment for the one who does the assembly, marketing, taxes & accounting, shipping package, refunds and defects, payment for someone to produce it or the usage of your existing equipment, etc. if you add all of these, you will see that it's not cheap.

This looks great! I've considered building a simple device with an LED matrix that looks similar to this, but could never figure out what gives the LEDs the muted look. All of the devices mentioned here (Tidbyt Gen2, Lamarca, Ulanzi, even the busy.bar) have it. Is the back-pannel just an LED matrix with a custom acrylic in front of it? How do they ensure the light from individual LEDs doesn't bleed into its neighbor?

> custom acrylic

While I'm not an expert, my own experimentation suggests this is correct

I wouldn't swear to it but from mine it looks like there's a grid of light guides between the led PCB and the front screen to prevent any cross bleed. The front screen is translucent but not transparent (think heavy tinted window) acrylic which gives it the muted look.

It's pretty good hardware wise, it would be hard to knock up DIY for $50 even just in BOM.

Edit: teardown in German https://youtu.be/-Dn3A5V8ZPo @ 04:30

This looks exactly what I have been looking for to put outside of my home office to keep my family from interrupting me during work meetings. Thanks for sharing it!

The “Live on air!” sign that triggers with Zoom (or Slack) is a very common usecase.

I wonder why it’s not better addressed. It needs to 1. be out of the office, on the door, 2. therefore bluetooth, 3. always on, and 4. it’s simple on/off light!

This 16x32 RGB LED panel (6.75"x2.75", USB powered, Bluetooth programmable) was $15 for a while, now $26: https://www.amazon.com/dp/B0CP5P7RY7

Programming it with your own code is still a mess, see "Panel Communication": https://github.com/auc0le/JT-Edit

Could be even cheaper as a string of addressable LEDs + some arduino board.

But quite some people are happy to pay the extra $174 for not needing to hack together software, a housing, physical controls, etc.

Yes, exactly, thank you! I have a Tidbyt that I enjoy but it's pricy and has a subscription local API. I thought the thing in the OP might be a discount smart home alternative and was hoping to find exactly this kind of alternative recommendation in the comments.

Neat! This is very close to what I want. I am looking for a very affordable device like this to affix to my home office doors. I would like it to be programmable allowing me to set the status to Don't Enter when I am having a Zoom call, etc.

Very simple if you flash it with awtrix, it has a neat JSON API.

I’d like it to have buttons (the apps Ulanzi mention are view-only).

Neat! Can't tell if it has a speaker at the back or not. Would like to play sounds or alarms...

I'd love to attach this to a PoE to USB-C ethernet adapter to talk to it over API via hardwired. Still looking for something like that. The flipper busy bar seems to at least have some connectivity over USB.

It has a small piezo buzzer, and you can use it to play RTTTL sounds. https://blueforcer.github.io/awtrix3/#/sounds

I have to warn that it sounds like hot garbage though. The neat thing with ESP32 devices is that you can make it sound okay using its built in 8-bit DACs, or great using I²S.

Speaking of hardware hacking; you can also get POE/LAN adaptors for the ESP32, if you have free hardware pins left for it.

+1 for the hot garbage piezo, but as OP says the ESP32 has a lot of fun hacking potential and there's plenty of space in the case especially if you remove the battery.

ahh that's incredible. I've attempted similar projects with various devices over time. this looks cool!

I have 2 of them and love them, blueforcer firmware supports home assistant and I can mix it with automations

As I'm too late to edit - if you use it in a setting where it's always powered, you might want to consider removing the battery as a safety measure. It's a fairly simple hardware hack, various YouTube videos and blogs on the subject.

The Ulanzi TC001 is a great, cheap piece of hardware. I found a second-hand one for $20 and flashed it via USB with https://github.com/lubeda/EspHoMaTriXv2, a more practical firmware if you already have a bunch of ESPHome devices at home.

Thank you! This is a nice rabbit hole to go down to. I've previously thought about building one myself, but this is probably way nicer.

That looks amazing! I'm ordering one, thanks for the tip!

Thanks!

Love the marketing on it: « the body is moderately thick and thin »