MacBook Air 11 - still great after all these years

I hand down my old laptops and phones to the kids who happily use them for years. Sometimes I try to hand down an update and are met with resistance - this (old) one still works fine, why should I change? When they do, they're stunned by the performance improvement. They are still going through the Intel to Apple Silicon transition.

Recently I got an 11-inch, Mid 2013, MacBook air back, and decided to get it going. The battery was completely dead. I paid $45 for a battery on AliExpress. They are easy to install on the 11 inch Airs and the battery came with the two screwdrivers needed.

There was quite a lot of dust and fluff to remove but the fan still moves well. My daughter got very good use out of this machine. It has a few dents in the edge but the screen is good and all the keys work. (I've done a lot of cleaning with a cotton bud but more to do). What's striking is that she's typed so much on it that the most used keycaps have worn the labels off them.

Even with "just" 4GB of RAM, the machine is surprisingly usable for email and web surfing. But being stuck on macOS 11 means that there are many apps that won't run and lots of sites complain about the version of Safari.

Some apps, like my beloved BBEdit, still keep old versions available.

I love the compact size of these and the fact that I could replace it for under $200 if the need arose means that this would be a good laptop to take somewhere where it might be stolen or damaged without too much anxiety.

Apple should make a new compact laptop. I love my modern Air but would be very attracted to something smaller for my messenger bag.

Tech Talk on ABC - Is AI killing the goose that laid the golden egg?

For more than a year many web sites have reported a dramatic decline in traffic, pointing to a broader structural change in how the web is being used by all of us. 

Many sites that create content - be it news or analysis - are funded either by advertising or subscription. The reduction in traffic threatens their business model. 

Peter Marks, software developer and technology commentator from Access Informatics,  joined Philip Clark and listeners to Nightlife with the latest tech news and information. Listen here and read Sue Ahearn's piece here.

Great interview with home brewer Paul VK3HN

Paul is an inspiring QRP home brewer. Great interview on a recent podcast. https://youtu.be/Rkd1o2PQI9M?si=gzKmEFHAueIDsdYK

Recommended.

Single step debug on a PICO

As you might guess, I'm really getting in to using the Raspberry Pi PICO for embedded development. If I can do a job in MicroPython I will but the C/C++ tools and the library they provide is a fantastic step up from the Arduino. The official plugin for Visual Studio Code is really excellent. I purchased the official debug probe and it seems excellent. 

You can compile and run with a single button but more interestingly you can single step debug and look at variables.

Claude code is a real help and just for fun I asked it to make a program that makes the PICO emulate a USB audio output device feeding the audio to a PWM DAC pin which I've added a simple low pass filter to.

It sounds great:

The debug probe makes it easy to install and run new builds. You don't need to unplug and plug while holding the Boot button, you just click the run debug button. Interestingly it loads the ELF binary rather than the UF2 binary that you'd drag to the mounted volume.

My interest in being a USB audio device stems from my interest in making an embedded version of at least bits of FreeDV RADE. 

The PICO 2 is quite a powerhouse although doesn't have enough RAM for what I have in mind. I haver some 3rd party boards on the way with extra RAM so we shall see. 

Running ML on a Pico

Before the days of FreeDV RADE (which uses multiple machine learning models to turn speech to features, transmit data over HF, and turn the demodulated features back in to speech audio; it was possible to run FreeDV with Codec2 on embedded hardware.

There was the SM1000 and the EzDV boxes.

I wondered if it might be possible to divide up the tasks and perhaps use several microcontrollers working together. I would not have attempted this before the days of AI tools like Claude Code but last night decided to give it a whirl.

This project captures audio from a MEMS PDM microphone. PDM is pulse density modulation and these little microphones have excellent sound.

LPCNet is the input side of the FARGAN vocoder. It turns speech audio into "features" which are a stream of 32bit floating point numbers. In FreeDV RADE, these features are transmitted over the air with an ML modem (but that's another story). The recovered features are turned back into speech audio with the Vocoder. 

This project live encodes the audio to a stream of features which it sends over a USB serial cable to a computer which has a python program which syncs up and captures the features to a file which can be decoded using one of the test tools with FreeDV.

Here's me talking in to it followed by a decode of the features captured.

I tried to get this going on a PICO but it could not keep up. Partly because it doesn't have floating point and must emulate it. The PICO2 keeps up and even has some head room. There is some work down sampling the audio from the microphone that could be dropped if I used an A/D input instead.

Now here is a features to speech decode side. Features are streamed over USB. Audio is PWM into a simple low pass filter. (My tests indicate that this can sound very good). So far the audio is understandable but quite poor.

I'm not sure that the Radio Autoencoder can fit on one of these but you never know... Any recommendations of easy to use embedded ARM boards? 

I'll share the code when it's a bit more polished. Not sure that this will be of interest to anyone but you never know.

Mineral Radio

 

Made me chuckle browsing AliExpress.

(Seems a little over priced if you ask me).

AI tools causing an improvement in software quality

I just saw the announcement of NetBSD 11. Software that has been around for many years. What struck me was this comment:

As you are probably aware, the number of security issues found or suspected everywhere has massively increased with the advent of AI tools. As a consequence, we can't publish a release without open issues. Instead of delaying the release further to fix them (new ones are being reported all the time), we've instead chosen to be transparent about this.

NetBSD is not alone, recently we've seen:

• Record AI Bug Fixes Push Google To Twice-Weekly Chrome Updates
• Microsoft ships largest Patch Tuesday on record and Microsoft Patches Record 622 Flaws, Including Two Zero-Days Under Active Attack
• Oracle Releases Record 1,449 Security Patches As Companies Face Patch Overload
• AI has become Apple’s latest bug detective

I've also seen big bug fix releases in popular software such as ffmpeg.

Last week I pointed Claude Code at my iOS app WSPR Watch which has so far had no AI involvement. I asked it to audit the code for bugs and it found about 20 issues, three of them critical. Some of the bugs are threading issues which can be hard to reproduce and even understand.

My own code has been under development for a decade and there's bits of it I can't really remember. AI tools are fantastic at reading a big codebase and noticing inconsistencies and errors.

People talk about "vibe" coding but bug finding is possibly the bigger win in the short term.

FreeDV Sunday net

Nice net this morning with VK2, VK3, VK4 stations participating. A few new stations which is always good to hear.

Again I ran the net using my macOS client FreeDVNeo. On the frequency were VK5FD, VK5RA, VK5AG, VK5ABE, VK3KEZ, VK3JCO, VK3GTP, VK2KNC, VK2BLQ, VK2AOO, VK3ZTR, VK2LUI (no activity though), VK3PT (first time caller), VK3FAR, VK2KNC, VK5JPL and me VK3TPM.

See you next Sunday from 09:30 eastern time normally on 7.197 but +- depending on band usage.