Category: Electronics

November 19, 2011 / / Coding

Open Source IDE and Toolchain for the STM32F4 Discovery on Mac OSX Lion

STM32F4-Discovery

ST Micro in the last few weeks was the first to market with the brand new ARM Cortex-M4 32-bit microcontroller core. The really interesting new feature is the ‘F’ in the name – this is the first low-cost, low-ish-power light duty microcontroller to include a built in, single cycle per instruction 32-bit floating point unit. In typical ST fashion, the development board is awesome – it’s got a built in ST-LINK/V2 programmer and in-circuit debugger on the top half. The bottom half contains the M4 and a host of fun peripherals to play with, including a 3-axis MEMS accelerometer, an audio DAC with class D output driver, a bunch of LEDs, and all GPIOs broken out to .1″ headers.

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August 17, 2010 / / Electronics

How USB Charging in iProducts Works

This may seem tirade-ish, and if so I’m sorry. This was spurred by the story posted here at TUAW. Basically, there’s a little USB pass through dongle that you can buy to eliminate your iPad “not charging” woes. TUAW kind of misses the boat on bothering to explain or understand it, so here’s how it works, in comment-on-the-article form (so read the article first):

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August 14, 2010 / / Electronics

Custom Breadboard

front view
My custom board

A few people asked about this. I’ve seen breadboards with binding posts before, but usually they’re nothing special, just some banana plugs near the board that you can screw a jumper wire into. I wanted something a little more full featured, so I whipped this up.

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August 12, 2010 / / Electronics

Touch Brightness Bulbdial

Bulbdial clock with breadboard and multimeter
Let’s make it touch sensitive!

UPDATE: People keep asking about the breadboard setup. Fair enough. I’ll throw together a quick overview when I get home today.
UPDATE: here it is: http://www.alexwhittemore.com/?p=462

The Bulbdial clock from Evil Mad Scientist is probably the coolest clock idea I’ve ever seen. Even cooler are my parents, who got the kit for my birthday.  The basic idea is that three rings of LEDs cast shadows onto a clock face to form H/M/S hands, somewhat like a sundial, with the hands slowly animating around. A lot of thought clearly went into making this kit, and it’s very nicely done, but there’s a major drawback: I want to use it on my bed side table, where I usually keep a clock, but it’s too bright for me to fall asleep! Of course, that’s been thought of too: in the normal view mode, the three buttons at the bottom of the clock are brightness up, down, and “mute,” which turns off the LEDs entirely. But they’re hard to get to buried underneath the frame of the clock, and it makes muting the display cumbersome in the dark. Let’s fix that!

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August 11, 2010 / / Electronics

How to make iPhone headsets suck less

Crappy Buds
Crappy Buds

Say what you will, but iPhones are pretty awesome, and so are the headsets that come with them. At least up until you put them in your ears. The inline controls are awesome, but the speakers are uncomfortable, lacking in low end punch, and do nothing for sound isolation. Other, much better headphones exist, but for under a gajillion dollars, none come with the same kind of inline controls. Here’s how to have the best of both worlds.

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August 1, 2010 / / Electronics

TI LaunchPad: First Impressions.

LaunchPad
Meet the LaunchPad

I’ve been playing with the TI LaunchPad the last day or two since I’ve been home in the US. I ordered two when they launched, but I was abroad and only just started playing with them, and I have some first impressions to share.

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July 18, 2009 / / Electronics

ATX -> Bench Power Supply Mod

Yay bench power!
Yay bench power!

WARNING WARNING WARNING! Switching power supplies have many BACs (beefy-ass capacitors) that can hold lots of juice long after you’ve unplugged the unit. Do not crack one open like I did without knowing what you’re doing, it could seriously injure you or at least be really uncomfortable when you shock the crud out of yourself. I’m not responsible if you do just that, don’t say I didn’t warn you. I have a cable I made with a brush at the end that grounds everything it touches, I use it to brush the back of all power electronics before I work on them. You should too.

This is a pretty common one, but I like to add flair. I needed a bench power supply. Sadly, bench power supplies are very expensive, and I’m a poor college student. What I do have are computers. Lots of computers. In fact, I just brought to the recyclers about 100lbs of computer waste from machines that are too slow for even my standards. Luckily, one thing computers have going for them is very refined, VERY powerful power supplies.

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July 18, 2009 / / Electronics

USB Breakout Cable

USB metering goodness.
USB metering goodness.

A while back I wanted to monitor how much current my iPhone could draw under different conditions. I had seen a cable before where somebody brought it into a project box with a couple of screws on top exposing the two unshorted positive leads and the straight-through ground (such that you could measure both current through the cable or voltage across it), but I felt I could make things both smaller and more fully-featured.

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July 18, 2009 / / Electronics

WESD51 Lockout Pencil Tip

May 24, 2009 / / Electronics

Soldering The Thinnest Wires Ever Conceived: Headphone Modding

Acrylic insulated wires stink, for sure, but when they're stranded and micro-fine, they stink WAY more.
Acrylic insulated wires stink, for sure, but when they’re stranded and micro-fine, they stink WAY more.

I may use this blog to post mainly iPhone or software related articles, but I am an electrical engineering student, and as an EE, I love me some good, clean hardware. Therefore, when my favorite pair of earbuds kicked the bucket the other day, my first thought went to the in-box iPhone headset and, more importantly, how much those earbuds suck. My favorite bang-for-the-buck earbuds EVER are Skullcandy Full Metal Jackets, primarily because I got them at TJ Maxx for $25. In general though, they have silicone pads that seal out sound, instead of the hyper uncomfortable iPod earbuds that fall out and sound like crap. I was super bummed when my FMJs broke, but luckily, the part that broke was on the plug end of the earphones. That is, both earbuds themselves still work fine, only the plug is dead. My thought was to cut the crappy iPhone buds off their cable (which includes a microphone and remote button) and graft on my beloved FMJs.

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