As each day goes by I learn more about the arduino and electronics and for each thing I learn I quickly realize that I don't have this or that component to make practical use of my new found knowledge.
When I bought my arduino I sort of had a clue that I would run into this so I stocked up on what's in the adafruit Arduino starter kit.
I got the following:
Resistors (100, 1k 10k Ohm)
Potentiometers (1k and 10k Ohm)
2 Tactile push buttons
2-5k Ohm CdS resistor
1 of each red, green, blue high power LED
5 diffused red leds
Other stuff I had lying around from before:
1 DC motor from an electric tooth brush (I can slaughter the other tooth brush aswell for another motor).
An assortment of leds in various sizes, shape and colours.
And thats about it!
Oh, I know I should get a L293D H-bridge for running the DC motor. But I probably won't stop there I probably also want to try using a servo, stepper, piezo and so forth...
So before I go and order the H-bridge can are there any generic components I should consider buying?
There seem to be about a thousand different types of capacitors, diodes, transistors, mosfets and whatnots... and I haven't got a clue as to where to begin.
I should add some general purpose NPN transistors and just a few PNP ones. You could also go for a couple of power transistors like 2N2222.
Add to that some capacitors for decoupling, lots of 0.1uF and a few 47uF.
Then some small signal diodes, and resistors in between those values you have like 470R and 4K7.
Then get some strip board for soldering stuff on to and some pin headers for attaching to the Arduino.
When I had to start building a few basic parts, I liked the Sparkle Labs Electronics Kit, which includes a grab bag of colorful LEDs, resistors, general-purpose transistors, wires, DIP switches, buttons, potentiometers, a breadboard, battery clips, and a booklet with some introductory projects.
2N3904 general purpose NPN TO-92
2N3906 general purpose PNP TO-92
LM317T adjustable voltage regulator. With two resistors you can get output
voltages ranging from 1.2V to 37V. A lot more convenient than stocking
multiple fixed regulators.
NTP18N06 TO-220 N-channel logic level FET 60V/15A
TL431 in TO-92. This is a shunt regulator. I would only get a couple of these.
Checkout the TI, On-Semi, National-Semi app-notes for this device. You
will find 20-30 pages of simple application circuits.
555 timer
I would get a few logic chips as well. AHC logic has 5V tolerant
inputs when run from a 3.3V supply. These are useful when
interfacing between 5V and 3.3V devices.