Soldering 101

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Intro to through-hole soldering

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

Circuit

  • 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?

Components