Blog
USB-C to Micro-USB Adapters
I have a Seek thermal camera, which works by connecting it to a phone and using Seek’s app to display the image, take photos, etc. It’s an older model, from back when there were two variants, one with Micro-USB and one with Lightning. I’m on my third phone since I got it, which does not have a Micro-USB port any more. But it’s easy to get an adapter from USB-C, right?
Read more →
Please Do Not Water This Tree
About two years ago, I made a little LED tree as a gift. An extremely simple design with 17 white 0603 LEDs soldered to magnet wire, twisted and bent to make branches, and combined them to a small LED bonsai. Electrically, all LEDs are wired in parallel and connected to 4.5 V via an LDR. This lets the tree react to the ambient brightness and helps it to great battery life. Read more →
A Better STM32F0 Prototyping Experience
This project started when I was particularly annoyed by existing development board options and cheap Chinese PCB prototyping services were starting to emerge. Thus, the path forward was clear, but let’s start with the problems I was trying to solve. When I’m talking about ‘development boards’, I mean boards like the Teensy models, Feather variants or blue pill: a PCB based laid out around a microcontroller containing very little extra circuitry; a ‘least common denominator’ of typical projects using that MCU, if you will. Read more →
ESP8266 Programmer
For the software side of some ESP8266 development, I bought a cheap ESP01 to USB adapter from AliExpress, expecting a programming adapter. What turned up on my doorstep, however, was just a USB-UART adapter which wasn’t able to drive the reset and GPIO0 pins. Luckily, the missing circuitry could be added easily.
Read more →
Using Desoldering Braid Bobbins for Bodge Wires
Don’t throw spent desoldering braid spools away! The bobbins are great for hand wiring prototypes and doing PCB repairs. They have the perfect size, and unlike a regular spool, the magnet wire won’t uncoil itself all the time.
Breadboard Test Points
Take a piece of wire, solder one end into a loop and the other one onto a header pin and you’ve got a very useful test point for breadboarding. A piece of shrink tubing shrunk only on one end nicely insulates connected probe hooks and an extra shrink tubing ring around the breadboard end keeps this cover from sliding off.
Building a Camera with a Rather Undersized Microcontroller
Disclaimer: This project was hacked together more or less in a weekend. Not much documentation is available besides the source code. If you want to build this (in the off-chance that you got your hands on one of these printer modules), you’d have to extract the schematic information from pinning.h and supply your own stepper motor driver and level shifter circuit. I had these thermal printer modules, 4 of them, after I bought them because they were cheap and seemed interesting. Read more →
A short reflection on direct laser PCB printing
I have been using a Lexmark E360d laser printer modified for depositing toner as an etch resist directly to PCB material for a while now. Details about the build have already been available on the project’s git repository, and this I’d like to focus on some comments on the actual usefulness of the project. PCB manufacture has been decreasing in its price, so I rarely use the ‘haxmark’ any more. It gets reactivated when I need a board fast and then it still does a decent job. Read more →
Arachnouphobia
Catchy title aside, this one is actually about deterring spiders. This small project started with my mother’s observation that a corner of her basement was spider-free since I had set up a NAS there. Rather than assuming that the vibrations/noises generated by the hard drive put the spiders off (like I would), she made a connection the Banana Pi’s irregularly flashing LEDs. That had to be investigated. A RGB LED, a breadboard, an ATTiny, and some batteries to test the hypothesis. Read more →
Pb Power bank
In preparation for being off-grid for a few days, I quickly built this ‘power bank’ around a 12 V 7 Ah lead gel battery. The circuit is simply pushed onto the battery’s 6.3 mm contacts and provides 3 USB ports. Charging circuitry is not included but the battery terminals are still accessible anyway.
Read more →