Difference between revisions of "Soldering 101"

Revision as of 22:15, 26 January 2012

We will solder a blinking, customizable name tag. We will also discuss and explain the design and the theory of operation.

A discrete astable BJT multivibrator feeding into a 74HC595 shift register, which drives the LEDs directly.
The shift register can serve up to 8 segments.
The LED matrix can partitioned arbitrarily column-wise: multiple columns can be grouped onto a single counter output.
each shift register output has one series current limiting resistor
multiple display modes:
- blink (CLK goes into enable)
- fill slowly, clear slowly (last output inverted feeds back)
- fill slowly, clear at once (last output inverted goes to reset)
- rotate (last output feeds back)
multivibrator speed can be adjusted with a pot
on/off switch?

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 * CR2032 holder, $0.4968 @ 100: http://search.digikey.com/us/en/products/3003/3003K-ND/227448
 * Pushbutton, $0.0916 @ 100: http://search.digikey.com/us/en/products/FSM4JH/450-1650-ND/1632536
-* DIP switch, $0.6204 @ 100, http://search.digikey.com/us/en/products/210-8MS/CT2108MS-ND/2503784
+* Pot, $0.3197 @ 100: http://search.digikey.com/us/en/products/3306P-1-105/3306P-105-ND/84994
 * PCB 5cm x 10cm, $1.498 @ 50: http://www.seeedstudio.com/depot/fusion-pcb-service-p-835.html