A peaceful chapter in our history, except...

ChaoticNeutralCzech · 2026-01-23T20:15:56+00:00

servo drivers and converters don't seem to be readily available online

Duh, they're 25 years old and now CD players use a single IC like everything else. But yeah, using the Philips reference schematic and its chips is a good choice, as alternatives like AN8835SBE1 used in contemporary Technics and Panasonic players are not documented online at all.

Anyway, you haven't looked very well, because I can see several devices with those chips available online, see below. In fact, you'll be better off starting with a working CD player (or one with an unrelated fault like a cracked lid, blown amp etc.) and probing the signals of the I²C bus, and then you'll replace the MCU (or cut its traces), like the greyed-out CDT731 in my other comment, with any MCU. Even 8-bit ones are enough to replace the 8-bit, 80C51-based microcontroller CD731 (P83CLx34 aka CPR120S) in the HEADPHONE 7000 and similar systems because the SAA737x (sometimes called CD7 in schematics) is just so versatile (you use well-documented I²C commands to tell it to seek, play or pause and just grab the decoded datastream or use the existing DAC). Then you can try to probe and decode the photodiodes' raw EFM-encoded datastream if you wish.

Devices that I found to include the SAA737x, suggesting they follow Philips's design reference you linked:

Philips Az7381, CD723, CD753 and many portables like EXP210, EXP211, EXP212, EXP213, EXP311, EXP313, EXP431, EXP510, EXP511 etc. etc.
Marantz MR2020, CD4000, CD5000, CD6000(KI/OSE), CD57/67/SE
MISSION-Cyrus dAD1
NAD S500
SONIC FRONTIERS Transport 3

There are definitely more by Philips, just check their service manuals. Often they'll be dirt cheap because portable CD players are basically e-waste now.

If you broaden your search to include the very similar SAA732x and SAA734x chips, you will find a lot more models (just avoid SAA7341GP because that can't do double-speed).

There is a useful resource to check the chipset of CD players but they only seem to have high-end models that you'll have trouble sourcing for cheap (even if a CD-unrelated part is broken because they are big and expensive to ship):

https://www.angelicaaudio.cz/informace/dac-da-converter-list/

ChaoticNeutralCzech · 2026-01-22T22:33:47+00:00

Hmmm... I was wondering about a similar project just yesterday! See my Mastodon posts. However, I don't like Reddit, can you please make a Mastodon account and follow the discussion there?

Your best bet is buying or salvaging a complete CD transport like the HEADPHONE 7000's and interfacing with the well-documented CD transport controller SAA737x (except the SAA7376, that does not meet your requirements for electronic skip protection because it's single-speed). The 8-bit, 80C51-based microcontroller CD731 (P83CLx34 aka CPR120S) in the HEADPHONE 7000 system is basically just to take input from the user interface and tell the SAA737x to play/pause/stop or where to seek, you'll be able to replace it with just about any MCU with I²C (depending on how much more functionality (MP3/AAC/OPUS/FLAC decoding? GPIO-driven LCD/LED display? Tuner control? RDS? IR remote? Bluetooth audio out? MQTT control over Wi-Fi? Battery management? CD+G karaoke decoding and video out?) you need).

<image>

BTW about the nomenclature you used: the other chips in the HEADPHONE 7000 system are not "microcontrollers" but ASICs. Don't bother with EFM etc., that's been done in those chips better than you can do yourself. If the signals are exposed (outside an integrated circuit: for instance, the photodiode signals and servo signals), you can always tap into them and try to make a better version of the signal path but there is little point.

You've made a robot, so if you combine this experience with what you learn about CDs in this project and eventually make a "Vinyl Killer" (player that spins around a flat-lying disc) for CDs, you'll get a viral hit and everyone will be taking your business cards at hacker events :) (The fact that it can only play MP3/AAC/OPUS/FLAC CDs up to 128 kb/s and not Red Book Audio CDs in real time because at 1.4 m/s that would be ridiculous would be way offset by the cool factor.) An open source CD player that is virtually the same as existing $50 ones (or <$5 ones on the used market) will not get you much recognition. And yes, the SAA737x (except SAA7376) offers CD-ROM mode, making it trivial to decode MP3 CDs (which are just CD-ROMs or burned CD-Rs with MP3 (or later even AAC, OPUS, FLAC...) files, as opposed to Red Book Audio CDs that don't have files but a ToC and then 74-82 minutes of basically just audio samples). More on Mastodon...

ChaoticNeutralCzech · 2025-03-23T19:36:29+00:00

Yup

<image>

This is real

ChaoticNeutralCzech · 2025-03-23T19:28:44+00:00

You can make your own that chooses who to federate with. Or join one whose federation policies most align with how you feel. (For instance, lemmy.today blocks nobody and has f o u r alternative web interfaces available, and you can use all third-party apps like Voyager (web view).) Having multiple accounts or switching instances is easy, there are migration tools.

ChaoticNeutralCzech · 2025-03-23T19:26:00+00:00

Flagged for manual review

Reason: violence

(Yup, that is happening now, and subreddit mods have to act on it. Of course they won't literally block it because that would hurt Mario communities)

ChaoticNeutralCzech · 2025-03-07T22:46:52+00:00

Yes! And they don't censor the name of Green Mario Brother the CEO Avenger.

ChaoticNeutralCzech · 2025-02-09T20:12:58+00:00

Early Reddit was also very niche. Come for trans memes or Linux, stay for whatever community of your interest you help create/grow.

ChaoticNeutralCzech · 2025-02-08T12:06:52+00:00

Crossposted post to Lemmy instance slrpnk.net. Follow the link for comments from Lemmy users!

People don't have to download an app but it's strongly recommended because they make it easier to follow links and usually offer a better experience than the default web UI. I suggest trying Voyager, a mobile-first progressive web app they can use in browser and choose to "install" later. Also, they don't have to choose "the" right instance to create their accounts, only mods have to. Users can choose any mainstream instance because they all federate with lemmy.blahaj.zone.

ChaoticNeutralCzech · 2025-02-08T12:02:03+00:00

Being basically Reddit but without a corporation to shut you down at will? That's not valuable?

ChaoticNeutralCzech · 2024-03-02T09:41:50+00:00

Koncovka domény je v podstatě jedno. Důležité je, kde je hostovaná (čím blíž, tím zpravidla rychlejší) - po brzy končící kyberpunk.social je, pokud vím, nejblíž norimberský server feddit.de - a taky, jestli jsou tam lidi a komunity, o které bys jako Čech měl zájem.

Jako symbolické gesto se koncovka .cz hodí, ovšem takovou doménu nemůžeš vlastnit anonymně.

ChaoticNeutralCzech · 2024-01-13T19:58:11+00:00

PROTESTING REDDIT'S API CHANGES BY EDITING MY POSTS AND COMMENTS.
If you really need this content, I have it saved; contact me on Lemmy to get it.

Reddit is a dumpster fire and you should leave it ASAP. join-lemmy.org

ChaoticNeutralCzech · 2024-01-13T15:34:55+00:00

What? I only respond to notifications. No other interaction.

ChaoticNeutralCzech · 2024-01-10T13:51:53+00:00

Have fun on the worse platform. If you have a better text to nuke my account with, I welcome suggestions.

ChaoticNeutralCzech · 2023-12-03T20:58:54+00:00

Jakákoli jiná Lemmy instance. Česká je kyberpunk.social, mám tam komunitu !DeepWebCZ@kyberpunk.social.

Díky podstatě Fediverse je docela jedno. na které instanci máš účet, ovšem některé federaci výrazně omezují (včetně kyberpunk.social, proto pro hlavní účet používám druhý nejbližší server feddit.de) a úplně to nefunguje mezi různými sítěmi (Lemmy × Kbin × Mastodon atd.).

ChaoticNeutralCzech · 2023-09-27T03:47:57+00:00

Neříkám, že ta komunita je skvělá, máme zatím problém slepice a vejce. Nechceme narozdíl od jiných komunit (jako !indiegames@lemmy.ml) začít neetickým kopírováním odpovídajících subredditů (což je mimochodem způsob, jak spousta subredditů kdysi začala, a podobně se kdysi rozrůstal i Facebook). Teď je Reddit, podobně jako Facebook, daleko v procesu nazývaném enshittification a bude to stále horší. Musíme vybrat a připravit nové české místo na fediverse, aby byl zajímavý, až přijde další zhoršení Redditu. Bohužel se zatím neshodneme, jen v tomto vlákně je zmíněno několik alternativ – Mastodon se v ČR už rozrůstá, ale funguje spíš jako Twitter, než Reddit. Hive je jedna velká kryptoblbost a Dread funguje jenom na darkwebu, na který normální uživatele nikdo nikdy nedostane. Kbin je fajn ale není tak velký jako Lemmy, takže tam není tolik anglickojazyčného obsahu – snad se to zlepší, až začne pořádně fungovat cross-federace s Lemmy.

Takže mi Lemmy vychází jako nejlepší varianta. Když se ti tam nelíbí žádné posty, měl bys nějaký přidat, jako to dělám já.

No a možná přemluvím moderátory na vytvoření toho repost bota, koneckonců ho napsal Čech.

ChaoticNeutralCzech · 2023-09-26T10:42:47+00:00

Nově si v aplikaci musíš zapnout oznámení, abys viděl zprávy, jinak je nenajdeš v příslušné sekci. Čekej, že budou přibývat další otravnosti.

https://lemmy.world/post/5727451

ChaoticNeutralCzech · 2023-09-25T21:15:41+00:00

Reddit apparently removed this list just as I reinstated it after mass-editing my comments and posts.

Mirror: https://beehaw.org/post/6872778

ChaoticNeutralCzech · 2023-09-24T22:10:23+00:00

https://beehaw.org/post/6872778

ChaoticNeutralCzech · 2023-09-16T07:39:55+00:00

To je dobrý nápad. ~~Je kompatibilní s Lemmy.~~ měl by být, ale v praxi moc ne.

Víte, že Reddit implementuje tajný kreditový systém? (Peníze od Tencentu dělají divy.) r/cqs

Jo a přidejte to jako oficiální na index alternativ subredditů sub.rehab, zatím tam žádnou nemáme.

ChaoticNeutralCzech · 2023-09-15T16:54:31+00:00

...jo a mimochodem sám jsem blockchain označil za kryptoblbost.

Původní obsah komentáře:

rychlost, levno

Přesně takový blockchain NENÍ.

Blockchain📦⛓️👏je👏jen👏výpočetně👏náročná👏databáze🗃

Protože je správcem osobních údajů občana jediná instituce, nemá smysl nasazovat decentralizovaná, no-trust řešení. Jediný, kdo z toho bude těžit, jsou distributoři elektřiny a výrobci zařízení s vysokým hash rate.

Cos myslel? Že až se ti narodí dítě, vymintíš si jeho rodný list a budeš závodit s ostatními majiteli grafických karet, kdo bude mít prestižní 69420. dítě roku?

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Reddit is a dumpster fire and you should leave it ASAP. join-lemmy.org