Micro is Beautiful

Getting My Hands Dirty

Being manually inept, the part I looked forward to the least with my new hobby was soldering. Past attempts usually ended with unsightly results and lots of frustration.

But Hail the Internets!

Dave Jones from the unmistakably Australian EEVBlog recorded a great three part tutorial about soldering. The videos cover everything beginners like me need to know:

1. Choosing the right tools and materials
2. Basic soldering technique
3. Mildly advanced SMD soldering

Dave explains all steps and choices in a logical, entertaining, and last but not least, very motivating way. He makes it look so easy!

Freshly motivated I splurged on the recommended Hakko FX-888 soldering station (which costs less than $100, my biggest expense for my new hobby so far.) I skimped on the solder wire as I still had some left in my toolbox and found Dave’s recommended size and composition only by the pound. Add two inexpensive hand tools, tweezers and flush cutters, a flux pen, and I’m ready to roll.

How did it turn out?

I can report success!

After a bit of exercising with wires and spare parts I was brave enough to put the solder iron on a real circuit.

The MSP430 LaunchPad comes with headers to connect peripherals. There's a set of female headers to connect wires or stack a shield, and a set of male headers to stick the LaunchPad on a breadboard. Both need to be soldered onto the LaunchPad.

I opted for the female headers and here’s a close-up of the result.

As you can see it went really well and I can confirm that it is as easy as Dave makes it look. It’s even fun!

With success I got cocky and tried out my new skills on my first, somewhat largish SMD component. The LaunchPad comes with a small 32.768kHz crystal (1.5 x 1.5 x 6.7mm) used for real time clock applications.

While the end result is not perfect, I think this one turned out quite usable too :-)

I’m not sure why I failed with soldering in the past. Probably a mix of lack of proper technique and unsuitable soldering tips were to blame.

Now I look forward to my next soldering project with confidence. Thanks Dave!

The TI MSP430 LaunchPad

This is my new computer.

Well, to be precise only that 14 legged critter on the socket is. The area to the right of the dashed line is its playground.

The crowded space to the left hosts two much more powerful computers. One is used to program and debug my new computer whereas the other handles USB communication with a PC.

The whole setup goes by the name of LaunchPad and it is the platform to program and experiment with Texas Instruments' MSP430 Value Line family of microcontrollers.

At $4.30 the MSP430 LaunchPad is a steal. It literally costs less than a visit to Starbucks! And the kit even includes a second microcontroller, in case I get bored with the first one. Or more likely, in case I inadvertently kill it with excessive voltage.

Microcontrollers (MCUs) are completely self-contained computers. Besides a CPU on a single chip they contain RAM, ROM, programmable I/O ports and a random set of peripherals.

The MCUs included with the LaunchPad are MSP430G2231 and MSP430G2211.

Both have a 16bit CPU that can run at up to 16 MHz. Though you typically operate them at slower clock speeds to conserve energy. At 1 MHz these chips draw about 0.22 milliampere, which translates to more than a year of operation on two AAA batteries (if my math is correct and the project rather boring without any other components). When idling, i.E. waiting for an internal or external event to wake them up, usage drops to a ridiculous 0.5 to 0.1 microampere. Too bad batteries don't last 1000 years :-)

Unfortunately the next set of specs is far less impressive: 2 KB of flash memory to hold your program and 128 bytes of RAM for runtime variables. There are other members of this family with up to 256 KB of flash and 16 KB of RAM, but in general size, cost and power considerations are keeping memory options rather spartan.

Talking about physical size: The chips that I got measure 20 x 6 x8 millimeters. That's the human scale version. The same MCUs are also available in assembly-robot-friendly 4 x 4 x 1 mm. Cost ranges from $2 for a single piece to less than 70 cents if ordered by the 1000's.

To round things off my two MCUs offer 10 I/O pins and one 16 bit timer. The 2231 in addition has an 8 channel 10 bit analog to digital converter, a temperature sensor and a USI. The last item is a kind of serial controller that talks to other chips using protocols like I2C and SPI.

Thew! Quite a lot of stuff in such a small package. In the next post I will write about how to actually make it do something - probably not something useful yet, but at least something.

 

Hello World

Ever since I got bored with BASIC and started writing 6510 assembler 25 years ago on my Commodore 128D, I was fascinated by the results that can be squeezed out of a few basic commands, a bunch of auxiliary components and some wires. And ever since I traded up to an Intel i386DX powered PC a few years later, I regreted each new level of complexity and new layer of abstraction required to hide it.

Many things we take for granted today were unthinkable a short 20 years ago. Powerful machines, operating systems, programming languages and development tools let software engineers and hobbyists build systems of bewildering complexity and deceptive simplicity.

Today's "Hello World" is compiled into bytecode, linked with string and output libraries, interpreted by a virtual machine, a string gets passed down through multiple levels of operating system calls and window managers, converted to bitmaps and handed over to the display driver and graphics card, some bits are sent over a wire to a display which in most cases is yet another computer with many layers. And while taking care of "Hello World" your computer and connected peripherals will do a hundred other way more complicated things.

Can you see why the assembler programmer in me is longing for a simpler computing world?

People tired of today's global high speed society walk or bike across countries and continents. My resolution is to tinker with small and simple computers, also known as microcontrollers.

Wish me good luck and this blog a long and prosper life.

Adrian