Simulating audio effects with SPICE

While I was looking at some audio effect circuit schematics at the internet, I though that it would be nice to try to simulate them SPICE first and listen them, before building them to confirm if they sound good or not ...

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Toaster oven reflow controller

Nowadays many of the most "exiting" chips come only in leadless packages, such as BGA and QFN which are hard or impossible to solder just by soldering iron, because leads are under the chip where they can't be reached. These kinds of chips are usually soldered using reflow soldering ...

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I made a Geiger counter

Ionizing radiation is something that almost anyone finds exciting (or scary) and I've also been for long wanted to build a Geiger counter

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Fast brainfuck microprocessor

Brainfuck is a minimalist programming language. It's mostly a toy and writing any real programs with it is almost impossible. Its design is very simple, the whole language has only eight valid instructions which operate on an array of bytes initialized to zero. Data on the array is manipulated ...

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Datapath of my PIC16F84 microprocessor clone

PIC16F84 is old 8-bit microprocessor made by Microchip. It was once very popular among the hobbyists, because of its low price. It was the first microprocessor I started to use so I thought it would be fun to try remaking it in VHDL. The source code is open source and ...

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UART designed to be used with FSM

Some time ago I needed an UART for a project. Things it needed to do were very simple and I didn't want to add a microprocessor to use UART and instead decided to just code a simple finite state machine to use it.

But I couldn't find a ...

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Progress on evolutionary circuits

If you haven't been reading my last entries, I have been working on a program that tries to design a circuits using genetic algorithm that fulfill the requirements given by the programmer. Read this entry for an overview what the program does and how it works. In this post ...

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Metastable transistor circuit

In my previous post I wrote about a circuit that would change it's output depending on what was the spice simulations DC sweep range. Today I investigated the circuit a little and I was able to remove lots of components that didn't affect the bug and this is ...

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Evolutionary algorithms and analog electronic circuits

I've been working for a while on a program that automatically generates analog electronic circuits using evolutionary algorithms. It's still very much a work in progress, but I've used it to generate some useful circuits. Current workings of the program is as follows:

  1. Programmer decides a goal ...
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Approximating the cutoff frequency of a filter

A long time ago I read from some book, probably some of the Jim William's or Bob Pease's books, interesting trick to approximate the cutoff frequency of a simple low or high pass filter. Below is equation for the cutoff frequency of a first order low or high ...

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