Share this page!

Matthew Garrett Profile picture
Twitter logo
15 Feb, 4 tweets, 1 min read
These lights had a non-smart controller and the blue was consistent along the entire length. I've tried multiple WiFi and btle LED strip controllers and all have this behaviour - red and green are fine, the blue fades quickly. All using the original PSU. Anyone have any ideas?
Oh, hmm, I'm actually only seeing about 4.5V on the output despite 5V on the input. Guess I need a beefier PSU?
Ok a nominal 2A PSU is still only giving me 4.9V on the output
I can get 5V on the output using my bench PSU but the blue still fades out in the same place?

• • •

Missing some Tweet in this thread? You can try to force a refresh
　

Keep Current with Matthew Garrett

Matthew Garrett Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @mjg59

Matthew Garrett Profile picture
16 Feb
In my time at Google I saw people earnestly engaging in racism, sexism and transphobia and arguing that they were just rationally debating the issues. On a mailing list with over 30,000 subscribers.
I don't think Google attracts this people disproportionately. They're a meaningful part of the industry.
The other common part of this is that when you push back, they'll just claim that this viewpoint is within mainstream conservatism and are you *really* trying to say that a position held by a significant percentage of the population is wrong or unacceptable
Read 5 tweets
Matthew Garrett Profile picture
25 Aug 20
If I ever get asked "What happens when you type a URL into the browser and hit enter" we are having an exciting journey via hardware interrupts, the kernel, display servers, toolkits and accessibility interfaces
Oh gosh I forgot about the scan matrix let's start there
This is *such* a terrible interview question
Read 6 tweets
Matthew Garrett Profile picture
12 Jun 20
People think that biological sex is this straightforward thing where if you have two X chromosomes you're female and if you have an X chromosome and a Y chromosome you're male and this is extremely not how things work.
The most obvious cases: you can have a single X chromosome. You can have three X chromosomes. You can have two X chromosomes and a Y chromosome. You can have an X chromosome and two Y chromosomes. Basically the only thing that doesn't work is having zero X chromosomes.
Ok so how about we say "If you have a Y chromosome you're male and if you don't you're female"? Well, no, that also isn't how things work. There's a gene on the Y chromosome called SRY. If that ends up on an X chromosome, you have XX people who are usually assigned male at birth.
Read 15 tweets
Matthew Garrett Profile picture
1 Jun 20
Inspired by @foone's amazing thread on double sided floppies (), a brief story about Amiga floppy drives
Floppy control on the Amiga involves four separate chips, but the interesting one is Paula. Paula was primarily known as the sound chip, but also handled receiving the raw data stream from the floppy drive.
Unlike PC floppy controllers, Paula didn't have any inherent assumptions about the format of the disk - Amigas can read both MFM and GCR encodings (and anything else that you come up with), while PCs are limited to MFM and have hardcoded assumptions about synchronisation marks
Read 11 tweets
Matthew Garrett Profile picture
29 Dec 19
Two Christmases ago I wrote a Linux driver for the CD drive in the Commodore CDTV but then Google asserted that it related at the time of conception or reduction to practice of the invention to the employer’s business, or actual or demonstrably anticipated research or development
Anyway I pushed it to github.com/mjg59/linux/tr… so you can have a preview of work that relates to either Google's business or actual or demonstrably anticipated research or development for a piece of hardware that was last produced 7 years before the company was incorporated
Anyway California Labor Code §2870 is a ride
Read 4 tweets
Matthew Garrett Profile picture
28 Mar 19
It's been over 90 days since I reported it and @TPLINK never responded, so: arbitrary command execution on the TP-Link SR20 smart hub and router (and possibly other TP-Link device)
TP-Link routers frequently run a process called "tddp" (TP-Link Device Debug Protocol) as root. It's had multiple vulnerabilities in the past and the protocol is fairly well documented. Version 1 has no auth, version 2 requires the admin password.
The SR20 still exposes some version 1 commands, one of which (command 0x1f, request 0x01) appears to be for some sort of configuration validation. You send it a filename, a semicolon and then an argument.
Read 11 tweets

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!

Like this author's thread?

Get emails when @mjg59 has new unrolls!

Check out other threads from @mjg59!

Read all threads by @mjg59