Ritiek Malhotra ritiek

Flashing an unbranded smart lightbulb to Tasmota

Whilst on holiday last week I thought i would do something productive but that seemed like work so I bought some cheap noname wi-fi smart LED lighbulbs off ebay and flashed them with Tasmota firmware, since the particular bulb I bought wasnt listed on the Tasmota Device Templates Repository and I have no idea if they accept an entry for a bulb with no identifying marks I thought i'd put something here incase its of use to anyone.

Reliability: I have at this point had 10 of these bulbs running for about a week, one of them has just died.

TL;DR

The pinout and device string for this light:

GPIO4 Cold White PWM 4

GROKKING NOTES

I liked the way Grokking the coding interview organized problems into learnable patterns. However, the course is expensive and the majority of the time the problems are copy-pasted from leetcode. As the explanations on leetcode are usually just as good, the course really boils down to being a glorified curated list of leetcode problems.

So below I made a list of leetcode problems that are as close to grokking problems as possible.

Pattern: Sliding Window

Think twice before abandoning X11. Wayland breaks everything!

tl;dr: Wayland is not "the future", it is merely an incompatible alternative to the established standard with a different set of priorities and goals.

Wayland breaks everything! It is binary incompatible, provides no clear transition path with 1:1 replacements for everything in X11, and is even philosophically incompatible with X11. Hence, if you are interested in existing applications to "just work" without the need for adjustments, then you may be better off avoiding Wayland.

Wayland solves no issues I have but breaks almost everything I need. Even the most basic, most simple things (like xkill) - in this case with no obvious replacement. And usually it stays broken, because the Wayland folks mostly seem to care about Automotive, Gnome, maybe KDE - and alienating e

Encrypted Btrfs storage setup and maintenance guide

Initial setup with LUKS/dm-crypt

This exemplary initial setup uses two devices /dev/sdb and /dev/sdc but can be applied to any amount of devices by following the steps with additional devices.

Create keyfile:

dd bs=64 count=1 if=/dev/urandom of=/etc/cryptkey iflag=fullblock
chmod 600 /etc/cryptkey

Linux Kernel Modules for NixOS

You can find what kernel modules are loaded using lsmod.

However some kernel modules are required at stage 1 boot. Basically preloaded in the initial ram disk before switching to the root filesystem. These kernel modules are mostly needed to deal with peripherals, storage devices, filesystems and network devices. You may need to be wary of these required modules:

sd_mod - SCSI, SATA, and PATA (IDE) devices

Open a webpage that uses the CA with Firefox
Click the lock-icon in the addressbar -> show information -> show certificate
the certificate viewer will open
click details and choose the certificate of the certificate-chain, you want to import to CentOS
click "Export..." and save it as .crt file
Copy the .crt file to /etc/pki/ca-trust/source/anchors on your CentOS machine
run update-ca-trust extract
test it with wget https://example.com

On Manjaro (arch) the location for the certificates is: /usr/share/ca-certificates/trust-source/anchors (low priority) or /etc/ca-certificates/trust-source/anchors/ (high priority) and the command to update is update-ca-trust extract.

	filename='yourfilename'
	filetype='text/csv'
	token='my oauth token'
	url='http://localhost/upload'

	curl "$url" \
	--form "data=@$filename;type=$filetype" \
	--form "name=somename" \
	-H "Authorization: Bearer $token"

	{ lib, buildUBoot, fetchFromGitHub, armTrustedFirmwareRK3328 }:
	let
	rkbin = fetchFromGitHub {
	owner = "ayufan-rock64";
	repo = "rkbin";
	rev = "f79a708978232a2b6b06c2e4173c5314559e0d3a";
	sha256 = "0h7xm4ck3p3380c6bqm5ixrkxwcx6z5vysqdwvfa7gcqx5d6x5zz";
	};
	in buildUBoot {
	extraMakeFlags = [ "all" "u-boot.itb" ];

	#include <SDL2/SDL.h>
	#include <cstdio>
	#include <list>
	#include <signal.h>

	std::list<std::pair<SDL_Joystick, SDL_Haptic>> joysticks;

	void shutdown_joysticks() {
	SDL_Log("Closing joysticks");
	for (std::pair<SDL_Joystick, SDL_Haptic> joystick : joysticks) {

	ffmpeg -f x11grab -thread_queue_size 64 -video_size 1920x1080 -framerate 30 -i :1 \
	-f v4l2 -thread_queue_size 64 -video_size 320x180 -framerate 30 -i /dev/video0 \
	-filter_complex 'overlay=main_w-overlay_w:main_h-overlay_h:format=yuv444' \
	-vcodec libx264 -preset ultrafast -qp 0 -pix_fmt yuv444p \
	video.mkv