attie

attie, 7 months ago to random

While getting lighting equipment ready for a panto, I re-encountered an issue that I've had to deal with in the past.

We own two 6-channel dimmer packs, that are typically addressed 1 through 12. We now own some RGBW LED fixtures, and use them in 4-channel mode.

We want the LEDs to be addressed 13-16 and 19-22... i.e: after the dimmer packs, and aligned to the 6-channel groups on our basic DMX desk.

However, after power cycling, the units set with the base address of 19 do not operate at all.

attie, 22 days ago to random

This is utterly wild... am I a little smooth-brained, or is this totally unrealistic?

• 200 Mbps compressed to under 1 Mbps
• Realtime, i.e: ~1ms latency or better
• Encode and transmit in <10mW (yes, including radio)
• Lossless
• High-entropy input

... if you succeed, just email them your solution - no mention of any reward or Nobel Prize nomination.

https://content.neuralink.com/compression-challenge/README.html

attie, 9 months ago to random

Did anyone else have 108 Mb/s Netgear WiFi equipment?

... was WiFi as "wild west" as I thought it was back then?

attie, 8 months ago to random

I'm still getting to grips with how utterly terrible my phone's camera is... perhaps I was just incredibly lucky with my previous phone?

Old: OnePlus 5
New: OnePlus 10 Pro

attie, 1 year ago to random

It seems my new mainboard has some gremlins... specifically the onboard NICs are non-operational after a prolonged period without wall power. A brief (~5 sec) power cycle gets them going - totally bizarre.

Anyone else with a ASUS Pro WS W790E-SAGE SE? ... or ideas?

I'm in contact with ASUS first line support, but that's not fruitful yet...

attie, 10 months ago to glasgow

I've spent some time with a camera today, and photographed the #Glasgow Digital Interface Explorer that @1bitsquared will be shipping... (revC3 with Case)

What a good looking product - well done @whitequark @esden @timonsku and everyone else involved!

attie, 9 months ago to random

It's been a while since I took an LCD apart... they've got so thin - nothing like the old CCFL backlights.

Shame about my finger grease and pants phone camera... There are a few layers missing.

1. The odd-LEDs lit @ 10mA over the unpowered / dark LCD
2. The odd-LEDs shining into the diffuser panel while held up
3. The odd-LEDs shining into the diffuser panel, laying flat
4. A close-up of the diffuser panel, showing the tiny spots (top edge is closer to light source, and has fewer dots)

The same scene, now with a clear/white diffuser panel held at an angle between tweezers. One edge touches the LEDs, while the opposit edge is held up.
The diffuser panel has been laid flat on top of the LCD. The assembly would be viewed from the other side in normal operation, and more layers would be present but aren't shown. In contrast to the LCD, a pleasing glow is now emitted across the whole surface of the diffuser. A piece of fluff, and some areas of finger grease are very visible.
A closeup section of the diffuser panel. Many tiny dots are visible, and the spacing changes across the surface according to proximity to the light source.

attie, 1 year ago to random

I can't figure this one from ASUS out... is it a licensing thing, but they didn't want to stick it on? 🤔

A closeup of the paper, which is actually a sticker, with text that suggests it's related to the presumably-AMI BIOS...?

attie, 6 months ago to random

I got a couple of these "LCD Writing Tablet" things - on a whim, out of intrigue, and for kiddo to scribble on.

One 12", and one 6.5".

It's honestly very-not-terrible, and kiddo loves it.

The smaller one has a sharper / thinner line, but they're both pretty great.

Any sharp-ish pressure on the "screen" will leave a "mark" (fingernail, supplied stylus, etc...), and pressing the button cycles the panel back to blank / black again.

https://www.amazon.co.uk/dp/B098JHYJF7

attie, 6 months ago to random

Does anyone have particularly favourite methods for electronically marking PCB revisions? I've done a few things over the years, but I'm interested to hear if anyone else has shiny methods - perferably avoiding extra BOM line items where possible.

Some of my previously-used schemes and ideas below. 👇

attie, 2 months ago to random

I feel like I'm loosing it... two boards behave differently, for what appears to be the same waveform.

This is an SWD scan against a SAMR34-XPro

A closer view of the start of the "conversation", showing a read IDCODE, followed by ACK, and data.

attie, 1 year ago to random

I can't decide...

Root on #ZFS - data integrity, snapshots, send/recv, more complex setup, lower performance

Root on #md - more straight forward, higher performance

... thoughts?

attie, 4 months ago to random

I share with you, a lesson in noise and self-heating.

These three series all measure the same thing, in close proximity on the same PCB - temperature.

• The top (blue) shows the temperature read by a 9-axis IMU.
• The middle (orange) shows the temperature read by a digital barometer.
• The bottom (purple, noisy) shows the temperature read by an STM32's internal sensor.

attie, 4 months ago to random

Sometimes patterns become obvious in the most unexpected situations...

How did I never know that vowels were separated by 3-3-5-5-5 constanants?!

attie, 8 months ago to random

As someone who has significant issues with numbers and maths (possibly even dyscalculia)... please let me share something with you that you'll probably think is simple.

I was playing with numbers and trying to re-arrange equations (something I never really managed during school) ... and managed this all on my own! 😇

A+B = B+A
AB = BA

... those are easy ...

A-B = -B+A

... I think I had that too ...

A/B = (1/B)*A

... that below my mind ... please correct me quickly if I'm wrong.

🤯

attie, 5 months ago to random

Please help me name a unit, or find an existing prefix.

NMEA provides longitude / latitude as Degrees and Arc Minutes (to 5 decimal places) - a resolution of approx 1.11m at the equator.

This will translate nicely into an int32_t with units of 1e-5 arc minutes per LSB (i.e: 10 μam per LSB).

What to we call 1e-5 arc minutes?... calling it 10μam feels boring, but that's where I'm currently headed.

e.g:
51°15.81498' N, 2°8.81592' W
becomes
+307,581,498 / -12,881,592

https://maps.app.goo.gl/2uABzBLRgtdtGU3W7

attie, 8 months ago to random

What's your preferred way to cut a trace? This one is ~0.5mm accross.

Also, what's that thing where the precision of your motor control scales with the magnification you're using?

attie, 8 months ago (edited 8 months ago) to random

Last night, "we" (@whitequark, @esden, @charlotte and myself) sat down and wrote up some new documentation for the Glasgow Interface Explorer.

It's looking incredibly shiny, and arrives just in time for the first of the Early Bird units arriving! 🥳

Go check it out, and please give feedback if you can.

https://glasgow-embedded.org/latest/intro.html

attie, 1 year ago to random

I just found out the hard way that the bulge at the motherboard-end of the AX1600i ATX cable is due in part to inline capacitors... and I now suspect this is the same for the PCIe cables too.

Quite frustrating, as this lump makes them very awkward to deal with.

I honestly wonder what good they're really doing...

attie, 4 months ago to random

When getting prototype PCBs made, I always make sure to get some extras - e.g: 6x assembled, 2x bare PCBs.

It lets you double-triple-extra check your boards when things are behaving weirdly. The manufacturing files only go so far in telling you the truth if a mistake was made during fabrication.

Does anyone else do this too?

Any particularly fun stories? 😀

attie, 8 months ago to random

As far as "smart tech" goes, this thing is literally painless and verging on magic. Honestly, an amazing experience.

Once you're set up, there are no buttons to press or switches to flick, or software to get annoyed with... just grab it and things happen ("things" being a 6-lead ECG streaming in realtime to your phone)

https://store.alivecor.co.uk/products/kardiamobile6l

attie, 2 months ago to random

So close! The internet points are real! 😀

attie, 8 months ago to random

I made a test card for the RedFit / SKEDD connectors! Someone suggested that it was neccesary to tweaking the fit (or at least worth it, I forget who, sorry!).

• The "Recommended Permanent" footprint is definately tight, but does fit okay... perhaps suitable for 1-time insertion (I broke off a locating peg while removing it, and the connector pinged across the room)
• "Recommended Debugging" is good, and removes easily enough.
• "+0.2mm" is honestly also probably fine for a debug interface.

The same test card, but with a connector inserted in the "Recommended Permanent" position.
The same test card (again), but with a connector in the +0.2mm position.
A close-up of the RedFit / SKEDD connector. It's like a standard IDC block, but instead of the typical holes, there are curved spikes sticking out. These spikes flex as they are inserted into a plated through hole, and exert outward pressure on the hole's wall. All being well, you get four points of contact.

attie, 4 months ago to random

Does anyone know what a realistic figure is for USB MSC transfer speeds over USB 1.1 / full-speed / 12 Mb/s?

attie, 2 months ago to random

I've just discovered that when using an incognito Chrome window, if you hover over an icon in the bookmark bar, it'll send a request to that URL. You do not need to click.

How do I know? I'm a weirdo who uses bookmarks to control my office lights, and I can turn them on/off without actually clicking the icon.