As soon as I get a chance…
Gotta _really_ learn electronics.
http://hardware.slashdot.org/article.pl?sid=08/05/06/2333256&from=rss
*Nothing* beats practical experience. Others have mentioned the Art of Electronics (which I have, and recommend as well). But practical experience is what really is the fun bits and what cemented it for me. I started from your position, and what I did was this:
1. Solderless breadboard, and an assortment of transistors, resistors, capacitors, inductors, 555 timers, op-amps etc. Do some simple circuits with them - make logic gates with BJTs and resistors, then do the same with mosfets (construct some CMOS gates out of discrete transistors for instance). Experiment with power supplies - buck converters to step DC voltages down, boost converters to step voltages up. Make sure you have several of each, because you’ll probably let the magic smoke out of some of them.
2. Decide on a simple practical project. I chose to make a solar power system for my garden - an 80 watt pv panel sourced from ebay. The first project was to turn on lights at night from the battery that had been charged by the panel in the day. This consisted of a voltage comparator to detect when the solar panel voltage had fallen below a certain level. The output is connected to a power transistor that turns on the lights.
3. More complex stuff. Get a heap of 74 series or 4000 series logic ICs and make something with it. This will teach you how the real world has a nasty habit of creeping into your digital designs: glitches, why we need decoupling capacitors, synchronizing clocks, that kind of thing. I built an RS232 nixie tube display. It had no microcontroller - the UART was entirely implemented in 4000 series logic. I built it on tri-pad proto board. This required me to learn how to build several things: a simple switch mode power supply to boost 12v to 170vdc for the tubes, as well as the UART.
4. It is your fate to home brew a computer. My next project was a Z80 based single board computer on 160x100mm (Eurocard). It has a CTC, PIO, real time clock, paged memory, 512k of flash memory and 32k of RAM, and an expansion connector. The flash was initially programmed by a similar circuit to the nixie tube UART, but with a simple address generator circuit added. Once the initial program was written, the Z80 system could write its own flash.
I’m now up to the stage where I’m doing more challenging designs, such as an ethernet card for an 8 bit system, implemented almost entirely surface mount components, the glue logic being in a programmable logic chip called a CPLD (the little brother of the FPGA). There are even more real world considerations that mess with digital design here: how to avoid ground bounce, PCB layout considerations to make the board work at all, and also a good bit of real fun programming: writing a driver for it in assembly language
There’s a great deal you can do as an electronics hobbyist: for example, you can make your own PCBs for fine pitch surface mount components if you have access to a laser printer: I’ve made my own PCBs for chips with 0.4mm pin pitch (that’s 0.2mm traces and 0.2mm spacing) using nothing but gEDA PCB (which is GPL’d PCB layout software), a laser printer, a clothes iron, copper clad board and etchant. Sparkfun Electronics have some great tutorials on hand soldering surface mount components, by the way. As you progress, you’ll want to be able to do this because there are a lot of interesting ICs that are only available in some sort of surface mount package.
