Nostr notes by Paul Evans

Looking for software recommendations, for a Raspberry Pi. ...

2026-02-07T21:42:49Z

Looking for software recommendations, for a Raspberry Pi.

Smallest/lightest way to redirect TCP port 80 over to some high-numbered port for running an http server as non-root.

I *could* run lighttpd or haproxy or somesuch; but is there anything even smaller?

#postfix question: My SMTP server has multiple IPv6 addresses. I ...

2025-10-10T11:30:46Z

#postfix question:

My SMTP server has multiple IPv6 addresses. I have attempted to tell Postfix which one to use:

```
smtp_bind_address6 = 2001:8b0:3f7::100:2
```

My SPF record says "only accept from +mx":

```
leonerd.org.uk. 14400 IN TXT "v=spf1 +mx ~all"
```

And yet, I'm getting SPF fail bounces from google because postfix tried to send from a different address - namely, the interface's default.

What's gone wrong here?

With no context whatsoever, I present this as today's hacky ...

2025-10-01T15:20:08Z

With no context whatsoever, I present this as today's hacky code snippet solved a small problem:

I was also pondering a `->\&` operator for this purpose. I ...

2025-09-23T13:17:04Z

In reply to nevent1q…x7x0
_________________________

I was also pondering a `->\&` operator for this purpose. I don't know if it's too subtle.

my $mref = $obj->\&method;

would basically act the same as

my $mref = sub(@args) { $obj->method(@args); };

but possibly be more efficient to implement internally, not needing a full CV clone and closure.

But I don't know if the syntax is a bit too subtle.

Maybe a subject for someone to write up a PPC? ;)

#makefile question I can set a variable for only one specific ...

2025-09-04T11:55:36Z

#makefile question

I can set a variable for only one specific target, by:

```
targetname: VAR="value"
```

I have a whole bunch of targets, and I wish the variable to have one value for one target, but a different value for every other target. Can I do that somehow?

There doesn't seem to be a target negation ability, or negative pattern match.

"Oh, when you said you were a prompt engineer, I presumed it ...

2025-08-24T13:33:11Z

"Oh, when you said you were a prompt engineer, I presumed it had something to do with LLMs"

"No, I just work very fast"

2/ Normally there's only one controlling node in charge of ...

2025-08-18T17:16:25Z

In reply to nevent1q…lmqs
_________________________

2/
Normally there's only one controlling node in charge of many others, but various "interrupt"-type situations call for any of the others to spontaneously emit a packet. These spontaneous transmissions cause bus contention if multiple nodes try to transmit at once. Since my protocol has checksumming and retransmission, I don't need to handle actual multiple access, I just have to detect this contention and have at least one side abort the transmission attempt and try again later.

A thread on an #electronics problem, relating to transmitter ...

2025-08-18T17:16:03Z

A thread on an #electronics problem, relating to transmitter contention on a RS-485 bus.

1/
I've been working a lot lately with a system based on an RS-485 bus, with multiple nodes on it. The bus talks async serial at 115.2kBaud, in short bursts of self-contained packets. Each packet has checksumming and sequence numbering, with a protocol of timeouts and retransmissions built on top of it for reliability.

I recently worked out why there's a weird dip in the sunlight ...

2025-07-24T20:07:54Z

I recently worked out why there's a weird dip in the sunlight graph of my weather station every day. It turns out the atmosphere sensor shelter box is taller than the optics sensor, and casts a very particular shadow.

> No, generative AI does not count as fair use, EU report ...

2025-07-19T16:49:39Z

> No, generative AI does not count as fair use, EU report finds

https://filmstories.co.uk/news/no-generative-ai-does-not-count-as-fair-use-eu-report-finds/

#TodayIAchieved Much faster display drawing code in my frequency ...

2025-07-06T11:00:10Z

#TodayIAchieved Much faster display drawing code in my frequency meter.
By the magic of making a second one, I can use one to measure the update time of the other. A total rewrite to more efficient code brought this from 14 fps to over double, at almost 35 fps.

Looking to find some folks who know about the events system and ...

2025-06-14T20:55:13Z

Looking to find some folks who know about the events system and TCB timers on the newer #AVR microcontrollers. I am encountering some strange behaviour.

Specifically, as far as I can tell, only event system channels 0 and 1 seem to be connected to event inputs on the TCB timers on my ATtiny1626 chip. Code which works fine on those two channels fails to do anything if all I do is switch it to any of channels 2 to 5.

This is troubling because in my current application, I need 3 channels.

I maintain that Windows 95/98 were the peak of usable UI design. ...

2025-06-11T16:22:01Z

In reply to nevent1q…y35n
_________________________

I maintain that Windows 95/98 were the peak of usable UI design. It's all been downhill since then

Thanks. Also, Ooof. Predictable yet still scary stuff. :/

2025-05-28T20:41:04Z

In reply to nevent1q…vwz0
_________________________

Thanks.

Also, Ooof. Predictable yet still scary stuff. :/

I've got myself a nice little portable USB-C soldering iron ...

2025-05-08T14:18:59Z

I've got myself a nice little portable USB-C soldering iron that uses T12 tips. It doesn't have a built-in battery though, so I'm in search of some sort of USB-C output battery pack that can output at least 15V, if not 20V. Are there any such?

What's EC or ECS in this context?

2025-05-06T11:36:44Z

In reply to nevent1q…cqay
_________________________

What's EC or ECS in this context?

builtin::trim was new in 5.36.0, so congrats - you already have ...

2025-05-01T09:41:06Z

In reply to nevent1q…p3dk
_________________________

builtin::trim was new in 5.36.0, so congrats - you already have it.

I forgot to design in some freewheeling diodes onto this 12V ...

2025-04-27T17:01:02Z

I forgot to design in some freewheeling diodes onto this 12V motor controller. Fortunately managed to find myself some DO-214-sized ones that fit nicely across the pin header for the connectors

#electronics folks: I'm looking for some kind of panel-mount ...

2025-01-20T12:05:05Z

#electronics folks: I'm looking for some kind of panel-mount low-voltage DC connector, for doing controlled power *out* of a control box, into some cable-attached devices.

DC barrel jacks would be OK, except that's for power into the control box. So I'm looking for something else.

Have considered such things as GX12 or mini-XLR, but both of those have panel-mount male and cable-mount female connectors, which is the wrong way round for power output.

Hmm? perlfaq7 was written a very long time ago and isn't ...

2025-01-08T16:25:20Z

In reply to nevent1q…e9av
_________________________

Hmm? perlfaq7 was written a very long time ago and isn't aware of all these newer things. In any case, I don't think it should be considered as a gatekeeper for what new ideas we can add.

Ugh. Laid out a circuit board with this INA219 chip and somehow ...

2025-01-05T19:32:06Z

Ugh. Laid out a circuit board with this INA219 chip and somehow failed to properly read the data sheet on these two pinouts. The two different package sizes have mirrored footprints. Of course I made the wrong one.

Well, at least that explains why the circuit doesn't work.

Nostr event nevent1qqsx4vy2kc6fvxs49j08v73l4s208l2lwh83qg680ny4a7ztjkvda2qzyzlux6cp86pwl5pjl38s432cu9avyj3npsa48gt46kgtw82zy69r6jgrpmq

2024-09-09T18:24:01Z

I'm really not having any luck at all with USB-C docks. :(

Ahyes, "inf" and "nan", the unfortunate ...

2024-08-16T23:30:51Z

In reply to nevent1q…4c3y
_________________________

Ahyes, "inf" and "nan", the unfortunate almost-a-number values