ST-Link/V2 SWD-JTAG Adapter

SWD AreaThe fantastic STM32 Discovery boards from ST Micro all come with an embedded ST-Link/V2 debugger onboard, including some jumpers to disconnect it from the target device for use as a standalone SWD debugger. Presumably, this is to allow for easy use debugging a custom end-product PCB, but it’s also useful if you have any other STM32 evaluation boards hanging around with no built-in debugger, but don’t happen to have a proper JTAG dongle handy. Here’s how to make an adapter.

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Aeropress: Some Things You Might Not Have Caught

That shell is for filters.

In case you missed some of the subtler points of the Aeropress system, these pictures may help. Continue reading

Approximate Sine Waves (how approximate is that?!)


I just installed a UPS the other day (an older Back-UPS XS1300, pictured) and noticed on the back it’s an “approximate sine wave” output. After reading the bottom closer, it’s specified that the device, under 25% load, has a THD of 55% and a maximum harmonic amplitude of 43% of the fundamental’s amplitude. Sounds pretty bad, but what does that really look like? Continue reading

Gvim with Powerline on Windows 8 64bit (BONUS: vim inside Cygwin)

victoryI love Powerline. Unfortunately, setting up just about any linux-centric software on windows is an everloving pain in the ass. Powerline is no different, and there don’t seem to be any start-to-finish this-is-what-worked Windows guides. Here’s mine.

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Using the STM32F4DISCOVERY on the Mac OS X 10.8.4 Command Line

6299osx-mountain-lion-iconThis will be effectively a copy of my previous post, but targeted at OS X. The gist is, get a toolchain, debug connector, and open-source firmware library set up to use the STM32F4DISCOVERY dev board from ST as quickly as possible on OS X. Unfortunately, it’s not QUITE as easy as on Ubuntu. Fortunately, it’s not a lot worse. Continue reading

Using the STM32F4DISCOVERY on the Ubuntu 13.04 Command Line

6299imgresThis tutorial follows the same basic outline as this post on but some things have changed since that was written such that it no longer works unmodified, and the various similar tutorials leave some bits out. My goal here is to get some custom code on the STM32F4DISCOVERY board as quickly as possible, hopefully paving the way in the near future for a full eclipse-based IDE setup.

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Need a Micrometer, Have Calipers

I needed to measure brake rotor wear tonight, but there’s a ridge on the edge where the pads don’t hit preventing an accurate measurement with vernier calipers. I don’t have a micrometer, but I do have a pile of weld nuts. Problem solved.

Greatest $.30 tool ever

I wanted to measure battery current on my new HexBright, and it turns out its something I’d like to do on a regular basis. So I made this: a strip of plastic cut from a blister pack, two strips of copper foil tape, and a couple of wires. Works great!

Simple Button, Complex Design

I pulled apart my car’s start/stop button today to redo some chipping paint that was bothering me. Naturally, I couldn’t stop at only the cosmetic plastic once I saw that there was a small PCB inside. There are two interesting things about this picture. First, look at the PCB: there are some electronics (and more than just regulators to drive the LED), an LED to illuminate the button, and nothing else. Continue reading

BMW E90 DIY iPhone Mount (prototype)

I’ve been thinking for a while about how I want to go about mounting my iPhone in my car. For a while I had one of those suction cup mounts that gently clamps onto whatever phone or case you have, but it was pretty cruddy and snapped the other day. It got quite in the way as well. Looking around today, I came across Kuda which sells a bunch of custom-fit solutions that look very good though are quite expensive. I thought to myself that something similar wouldn’t be too hard to fabricate myself for a few bucks at home depot.

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