How a 140-Year-Old Integral Transform Made Our Neural Network 18x Faster
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Insulating firebricks
I recently had to fix the door of my Grundofen, a thermal mass stove that provides a wonderful, radiant heat. A critical component had failed: the middle of the three Schamotteplatten (fireclay plates) insulating the inside of the door broke in two. While a simple replacement was an option, commercial vermiculite plates are expensive and
STM32 as automatic powerup after power failure
TLDR: Built a USB HID device on STM32 BluePill to wake headless servers after power loss. What started as an Arduino project evolved into a cleaner libopencm3 implementation, teaching us when direct hardware access beats abstraction. The Problem: Server Wake After Power Loss Power outages are a headache for server rooms. While servers can automatically
Understanding STM32’s Flash Protection
TLDR: STM32’s flash protection requires a specific sequence of key registers and timing considerations to unlock. This guide explains the practical steps needed for FPEC unlock, option byte access, and handling the power cycle requirements. The STM32’s flash protection operates through a sequence of key registers and timing requirements. Here’s what you need to understand
Blackmagic probe revisited
Turn Your $2 STLink Clone Into a Black Magic Probe TLDR: Transform that cheap Chinese STLink V2 clone into a proper debugger by flashing Black Magic Probe firmware. 15 minutes of work, intermediate difficulty, and a surprisingly good outcome for something that probably came in a plastic bag with no labels. Historical Context Back in
Cutting Solar Cells with a Laser
TLDR: It doesn’t work I have some Maxeon Sunpower C60 Cells at home. So not a whole panel, but the individual cells. They have contacts at the bottom, are flexible, and are very efficient. But also very big, so I tried cutting them. Settings used: 100% power = 20W @405nm diode laser 20
How to do logging with python and avoid duplicate lines
TL;DR: If you use the default example your handlers are duplicated in each object instance If you blindly follow the official python documentation at https://docs.python.org/3/howto/logging.html you will probably end up with duplicate lines like me. The reason for this is, that each instance of your object will add a separate handler to the default
Notebook Batteries don’t balance
TL;DR: Don’t trust the vendors. They only monitor the cells, they don’t balance them. Introduction It’s a less known fact that most notebooks don’t balance their cells. Maybe some do, but I haven’t found them yet. So I added an active balancer Buy it here: https://www.aliexpress.com/item/4000228067138.html What is this? This is not a regular
Evolution of Chinese Car Chargers
TL;DR: Chinese Engineering has surpassed Western Engineering [cmtoc_table_of_contents] Introduction I’ve shown some interest in Car Chargers in the past: Tuning a dual usb car charger Dual USB car charger update Quick Charge But the time goes on and today we apparently need Quick Charge to surpass the measly 5V 500mA of the original USB
PLA is not stable
TL;DR: Just don’t use PLA for anything you don’t want to fail I’ve had a bunch of PLA items suddenly break on me, with no idea why. Especially screws and tensional load bearing parts broke. For example my Delta Extruder gave progressively worse results and I had no idea why. Apparently it was flexing?
FDM: Printing too hot, too cold, and about right
Summary: The optimal temperature for FDM printers depends on numerous considerations [cmtoc_table_of_contents] Introduction When I embarked on my 3D printing journey, I questioned, “What is the optimal temperature?” Responses varied from 180°C to 280°C, leading me to examine calibration cubes in detail. Sensors In case you are unsure about your sensor type, you’re most likely
3D-Design with openscad
TL;DR: You can program 3D stuff with openscad For a long time I’ve avoided designing 3D stuff myself. The reason is that my spatial imagination is really bad. I even get lost or take the longer route in cities I know. It’s a disaster in an unknown territory where I try to take a ‘shortcut’.
Teardown: SportDV Camera
TL;DR: Just buy big brand or open source cameras I ride a road bike in Germany, Cologne. And you probably know that 1% of drivers out there who are crazy and trying to work out their personal problems in traffic. Recently, someone opened his car-door intentionally when I was riding by. In the aftermath, the
Measuring Capacity with one Port Pin
TL;DR: A tiny code sample which shows how to measure capacity with one port pin The ESP8266 module is now everywhere. With platformio you also have a simple setup and environment. But I had some problems measuring the capacity with this device. We are talking here about pF – nF, because I am interested in
Super Absorbers can help your plants
TL;DR: Put Super Absorbers into the soil. Your plants will recover better from droughts and moisture fluctuations are evened out I have one little Dypsis Lutescens palm which is always on the brink of dying. The reason is that it constantly struggling between being drowning and dying of thirst. So I tried out Super Absorbers.
Liquid thermal paste in laptop
TL;DR: Don’t use it in portable things as it cracks My laptop has become loud and slow over the years. This came from permanent 90°C CPU temperature and thermal throttling. From my experience, the manufacturer never uses the correct of thermal paste, so I opened my laptop up and applied Coollaboratory liquid pro thermal paste.
Learning a sine wave with LSTMs
TL;DR: Copy & paste the linked code to have working Neural Network as a starting point for your application Introduction I tried several times to get started with Deep Learning. But pretty much all the tutorials were outdated and it was just a lot of work with no result in the end. This time I
Deep learning made easy with Colaboratory
TL;DR: Get free a GPU and environment with Jupyter Notebook with this tutorial I always struggle to set up the environment for deep learning frameworks. It seems you need the right set and versions of hardware, OS, drivers,framework. And if you want GPU support, things get even worse. But google wants you to use their google
Connect Batteries easily
TL;DR: Use magnets to connect batteries Most Batteries contain Iron or Nickel. Just use a magnet to connect the battery. On the other side you can use one of those cheap copper-clad cables from china or alligator clips Bonus: The magnets automatically disconnect if they reach ~90°C in case of a short circuit.
Fixing a chinese 3D Printer: Part 2
TL;DR: I’ve invested way too much time and money in this thing Introduction I’ve printed for over a month now. Various things broke and some improvements weren’t improvements after all. New bed surface I’ve tried a lot. The best is borosilicate glass. It just works and the bottom is sooo smooth. This here
Fixing a chinese 3D Printer: Part 1
TL;DR: You have a lot of work to do until this is usable Introduction I’ve bought an Anet A8 für 143€, everything included. It’s a clone of the the Prusa i3 and available under all kinds of brandings and with every changing components. Here are the things I’ve learned on my way. Common Errors which have
Raspbian headless install over Wifi
TLDR; Configure your new PI without a monitor Just follow this guide to install your raspberry pi 3 without a monitor. It enables wifi and ssh in the default raspbian installation. install raspbian on your sdcard: export DEV=/dev/sdX; \ unzip 2017-04-10-raspbian-jessie-lite.zip ;\ cd 2017-04-10-raspbian-jessie-lite ;\ sudo dd if=2017-04-10-raspbian-jessie-lite.img of=$DEV bs=4M && sudo sync mount boot partition
Lowside current measuring gone wrong
TL;DR: Always take into account the ground bounce. Introduction I’m developing a software controlled Switched Mode Power Supply (SMPS). For this I need to measure current at ~250kHz. This is a recollection of the false assumptions and mistakes I made. The circuit I’ve decided to measure the current lowside as it seemed easier when I
Earn money with your smartphone
TLDR; Let your smartphone mine cryptocurrencies I like money. Money is even better if you don’t have to work for it. So I set up my smartphone as a zcash node. Zcash is similar to bitcoins: You exchange computing power for virtual money. This post is twofold: First the hardware modification to keep the CPU
Blackmagic probe
TL;DR: Flash new software to a cheap STLink v2 clone to get an integrated gdb Essentially, I just followed the the instructions in their wiki. I still had some problems guessing the pinout and documented my progress. Hardware: To program the controller with new software you need a second programmer. I used another STLink clone
ESP8266 + Arduino + Eclipse
TL;DR: PlatformIO offers a complete toolchain, libraries, makefile and IDE integration Making a new microcontroller work is hard. You need to get a feel for the surrounding community and the way the manufacturer imagined them to work. PlatformIO solves all those problems and more. What you get is: the toolchain package management for libraries makefile
The problem with cheap powerbanks
TL;DR: Cheap powerbanks are overrated I’ve bought a few powerbanks like this one: These are the common problems: 1. Outdated and underrated SMPS These power banks have to convert the battery’s voltage from 3.0V – 4.2V to the USB’s 5V. You can see the inductor with propably 3.3uH at the bottom left just above the
Enabling zram
TL;DR: modprobe zram num_devices=$(nproc) && \ sleep 1; \ for i in $(eval echo zram{0..$(( $(nproc) -1))}); do \ zramctl -t 1 -a lzo $i -s $(( 4096 * 1024 * 1024 / $(nproc) )); \ mkswap /dev/$i; \ swapon /dev/$i -p 1; \ done && \ sysctl vm.swappiness=100 && \ echo 0 > /proc/sys/vm/page-cluster
Verifying sdcards
TL;DR: Verify sdcards on the fly DEV=/dev/sdX && \ dd if=/dev/urandom bs=4096 count=$(( $(sudo blockdev –getsz $DEV) / 8)) \ | pv | sudo tee $DEV | md5sum ; \ sudo dd if=$DEV bs=4096 count=$(( $(sudo blockdev –getsz $DEV) / 8 )) \ | pv | md5sum I have a few sdcards which are probably
Dual USB car charger update
TL;DR: Chinese USB adapters work out of the box
I’ve bought a new car charger because the old one was too big. The new one is made from aluminum to dissipate the heat better and doesn’t waste that much space.
It’s 2.26 USD including shipping on aliexpress. I’ve expected the electronics to be garbage as the one before but i was pleasantly surprised:
A double sided PCB with plenty of vias and a good layout. I’ve checked the switching node with my oscilloscope (no screenshot) and everything is rock solid and no ringing. I couldn’t have done it better myself.
The components are good as well:
3.8+ kernel for Pogoplug
TL;DR attach dtb file to kernel and boot I’m running gentoo on a Pogplug E02 and had some difficulties with kernels after 3.7. These kernels use a new infrastructure called device trees to tailor the kernel to new hardware. Luckily this abstraction layer is already prepared for common devices. It just has to be loaded
ZFS-root on LUKS
TL;DR ZFS as a root device on top of LUKS I encrypt my devices. This saves hours of changing passwords in case a hard disk is lost. Additionally, I don’t have to think much about which data I save: passwords, signatures and photos. These are my notes in case I need to set up the
Working with Lua on an ESP8266
TLDR; use luatool to upload scripts Lua is a scripting language which has been ported to the ESP8266. After flashing the latest firmware you can connect to the module using screen /dev/ttyUSB0 You probably want to save your entered code over a restart. Nodemcu offers a whole file api which tells you how to manipulate
Wind Turbine: Cutting the blades
TLDR: I cut my blades using a chainsaw This happened a year ago. I never posted it because i “wanted to do it right and give good documentation”. But i think some pictures are better than nothing. Theory My goal is to cut 3 blades from the collected wood. Each blade is tapered. This means
Variable Frequency Drive over Wifi
TLDR: Set the waterpump’s power over wifi I’m using a Siemens Micromaster Vector to continuously drive a waterpump. This way, i can change the frequency and with this the power usage. Unfortunately, the inverter is placed in a wet hole together with the pump and i don’t want to climb down to change the frequency.
Wind Turbine: Fetching the wood
I need some wood for my wood turbine. The measurements needed for one blade are 50mm x 200mm x 1500mm. So i started collecting scrap wood from everywhere and i made some huge mistakes which you can learn from. For one, the wood should have been dry or at least approximately the same dryness. Some
qemu on gentoo
I’m running gentoo on a pogoplug. This is an embedded device with 1,2GHz armv5 and 256MB Ram. Unfortunately, big packages like gcc don’t finish. Thats why i set up a working qemu environment to emerge certain packages, zip them up, and unpack them on the working system. So the aim is to modify a backup
Repairing an USB-flash-drive
TL;DR: USB flash-drives can be repaired in Software. I have broken quite a few USB-flash-drives in my life. It’s commonly not the file system but something in the nand-flash itself, caused by too many read/write-cycles, caused by compiling me gentoo system. BTRFS states these errors: [30368.777688] BTRFS: bad tree block start 18446744073709551615 63586304 [30368.778927] BTRFS:
Opening a Qi Wireless Power Pad Charger
I bought one of those cheap chinese Qi chargers. It’s only $6.28, including shipping. It charges my Nexus 4 flawlessly and is definitively worth the money. The specifications say it draws up to 1500mA at 5V (USB). You can get the actual charging current via adb, depending on your device: adb shell “cat /sys/class/power_supply/battery/current_now” mine
Tuning a dual usb car charger
I’ve bought a dual usb car charger recently with the intention of modifying it. My intent is to use this charger to charge two Android phones at the same time with the maximum allowable current. Here you can see the charger. The connector to the left included a fuse. The eight-legged IC in the middle