my recent reads..

Blogging with Jekyll

I’ve had two blogs kicking around on blogger.com since around 2004 - tardate and pratalife. I decided to try porting and combining them on GitHub Pages using Jekyll.


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LEAP#222 Stair-step Generator

Once again I'm inspired to go and build a circuit by yet another great tutorial from w2aew.

This circuit generates a stairstep waveform by an ingenious combination of 3 circuit elements:

  • a "high" (265Hz) frequency pulse (555 timer) provides the charge to step-up the output
  • the step pulse feeds an OpAmp pulse integrator/accumulator
  • a low frequency pulse generator (OpAmp oscillator) provides the reset pulse that clears the accumulator and resets the 555

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub.




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LEAP#221 XOR with Resistor-Transistor Logic

Exclusive OR (XOR) operation is true only when the inputs are different.

An XOR may be constructed using combinatorial logic: an OR ANDed with a NAND. But can it be done with even more basic discrete components?

This circuit uses a diode-bridge and a single transistor - quite neat. It does mean however that there is no output buffer, in fact the output is powered from the inputs. I'm using an Arduino to drive the circuit and capture the output plot.

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub.




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LEAP#220 Arduino gcc toolchain

The Arduino IDE is the most convenient way to get started with Arduino, but it does obscure the underlying mechanics of building software for an Arduino.

How to do it from scratch? This is my experiement and guide to building software for an Arduino from the command line. I use a Mac and homebrew, so it is somewhat MacOSX-specific.

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub.



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