schottkydio.de

Hey electronics mastodon ... I have a little puzzle for you all.
A great many moons ago (almost 10 years) I needed some zener diodes for input clamping. Anything around 6v would do, so I bought a leftover reel of supposedly MMSZ4692 (a 6.8V zener) of ebay. I don't think I ever actually used any of them though.
Because I just tried to use one of them today and it turned out to be 3.4vish zener. So I checked the next one on the reel and sure enough 3.4v again.
Next I checked the datasheet and the markings on the diode. The diode is marked CDU, so if it was a MMSZ46something it should be a MMSZ4679T1G with 2.0v Zener voltage.

So I guess it's something completely different. Google tells me there is a CMHZ4706 marked CDU, but that's a 19v zener.

So does anyone have any idea what I've ended up with?

Short reminder that if you follow me on chaos.social you might also want to follow me on my own instance schottkydio.de , where the majority if my posts is going theses days.

I'd migrate the account, but as far as I can tell that feature is not 100% working in gotosocial just yet.

In the meantime here's a cat picture.

Did you know you can just type <return><tilde><point> in any open ssh session to activate the bandwidth saving mode for the session?

Do I have any golang experts among my followers?

I'd really like to know why uint32(float32(-1)) is 0 on my ARM system.

For a more complete example:
forum.golangbridge.org/t/inconsistent-behaviour-when-converting-float-to-uint32-on-arm/30247

Hmmm ... @anika got me this ultra sound levitation kit (www.olimex.com/Products/Soldering-Kits/Ultra-Sound-Levitation/open-source-hardware) by @olimex for Christmas.
Unfortunately I can't get it to levitate anything. I've already switched from USB to my lab power supply to keep an eye on the current, which looks okay to me (30-40mA) and I've started poking around with the oscilloscope. The transducers decent enough looking signals on both pins. The signals for pin 1 and pin 2 on each transducer are 180° out of phase as they should be. (The kit abuses the TX pins of MAX232EN as two 12v push pull drivers.) There is definitely a resonance point, with an amplitude peak when twiddling the frequency knob. So at least one the transducers is connected an doing something.
I've tried tried styrofoam pieces, tiny bits of paper and tiny bits of cotton. They don't appear to be affected by the sound waves at all. I've also tried to gently blow some smoke between the transducers, expecting some form of visible turbulence, but nothing happened.

I did some recreational coding today...
If you have a twitter backup archive, you might have noticed that most of the urls in that backup are replaced by t.co shortened urls. This means if something were to happen to this domain, all of the links in your archive will be b0rked.

So I made script to go over the files and replace them with their location.
It's not pretty and it's not fast, but it worked for me.

gist.github.com/LongHairedHacker/360ea2005c5a53bb126d4097f9e801e7

Hmmm ... Seems like my gotosocial does not give me all the replies under every post. Sometimes it looks alright and sometimes I can see a lot more replies using my chaos.social account. Folks replying directly to my toots seems to come through okay.

Maybe that's an effect of github.com/superseriousbusiness/gotosocial/issues/894

The combination of sengi (sengi.nicolas-constant.com/) and gotosocial (github.com/superseriousbusiness/gotosocial) seems pretty nice so far.

Feels a bit like tweetdeck.

Two problems I encountered so far:
1. I set the protocol to http in the gotosocial configs for testing stuff and I did not reset it before creating my account. gotosocial saves the urls for the inbox, outbut and other activitypub stuff in its database. Since many implementations don't follow 301 redirects for those URLs, things broke as soon as I switched protocol back to https. Fortunately I hadn't done much, so I simply dropped the DB and started over.

2. Sengi feels a lot like tweetdeck, but gotosocial does not implement following hashtags just yet. So I can't have hashtag specific columns.

Hello operator.... Is this the fediverse?