Overdrive guitar effects pedal


Eddie over at Bantam Tools shared detailed instructions of how to build this DIY overdrive effects pedal:

This project shows you how to make your very own effects stompbox! We’ll go through the steps of downloading the .brd file, loading the file into our software, milling the board on the Bantam Tools Desktop PCB Milling Machine, and soldering the components. This is a great tutorial for those new to milling printed circuit boards (PCBs) or for those who want practice soldering components to the board as a part of a larger assembly.

More info at Bantam Tools project page.

How to configure I2C sensors with Arduino


Edward Mallon writes:

I’ve spent the last year in the ‘uncanny valley’ of the Arduino. That’s the point where you understand the tutorials at Arduino.cc, but still don’t get much from the material on gitHub because trained programmers would never stoop to using the wire.h library when they could just roll their own in native C++ using the avr-g++ compiler.  The problem with establishing sensor communication at the level of the TWI peripheral inside the AVR is that there are so many fiddling details to keep track of that it quickly overruns the 7±2 things this average human can hold in his head at one time: Computers aren’t the only things that crash after a buffer overflow!  So this post is meant to be a chunking exercise for beginner-intermediate level people like myself who want to get a new sensor working using the standard IDE.  I’ve tried to distill it all down to things that I run into frequently, but there’s still a lot of material here:  So pour yourself a cuppa before diving in…

More details at Arduino based underwater sensors blog.

DIY through hole plating of PCBs


Jan Mrázek documented his experience experimenting with DIY through-hole plating of PCBs:

I’ve been thinking about though hole plating for several years. The general procedure is simple – you have to activate non-copper surfaces (make them conductive) and then you apply standard electroplating procedure. You can find many tutorials on the internet, however, most of the require hard-to-get chemicals for the activation solution. Few weeks ago, I noticed that the local electronic component supplier had started to sell Kontakt Chemie Graphit – a conductive paint. It’s basically a colloidal graphite in an organic solution. It is supposed to be used for making surfaces conductive to prevent static electricity discharges. This could be perfect for activation of the non-copper surfaces! So I gathered all the necesery chemicals and equipment and made a test run.

More info at mind.dump() blog.

ESP8266 Deep Sleep with Arduino IDE


Rui Santos has written a great guide shows us what’s Deep Sleep and how to use it with the ESP8266 in the Arduino IDE.

With most of the ESP8266 modules, you can’t change the hardware to save power, but you can write software to do it. If you use the sleep functions with the ESP8266, it will draw less power and your batteries will last longer. In this guide, we’re going to talk about Deep Sleep with the ESP8266.

See the full post on his blog, Random Nerd Tutorials.

Check out the video after the break.

ZX81 internal 16K RAM (reversible version)

pZX81 testing-600

Dave Curran wrote a post on his blog showing how he upgrades the ZX81 internal 16K RAM with a reversible version:

One of the common issues with the ZX81 is the good old RAM pack wobble. Depending on the state of your edge connectors on your ZX81 and RAM pack, it sometimes does not take much to interrupt one or more connections and crash the ZX81.
To get around this, I have done many ZX81 internal RAM upgrades, following the procedure I described in an old blog post – ZX81 Internal 16K RAM.
I had a request to do one of these, but to do it in a reversible manner, without cutting tracks.

See the full post on his blog- Tynemouth Software.

Microcontroller action potential generator


Scott Harden writes:

Here I demonstrate how to use a single microcontroller pin to generate action-potential-like waveforms. The output is similar my fully analog action potential generator circuit, but the waveform here is created in an entirely different way. A microcontroller is at the core of this project and determines when to fire action potentials. Taking advantage of the pseudo-random number generator (rand() in AVR-GCC’s stdlib.h), I am able to easily produce unevenly-spaced action potentials which more accurately reflect those observed in nature. This circuit has a potentiometer to adjust the action potential frequency (probability) and another to adjust the amount of overshoot (afterhyperpolarization, AHP). I created this project because I wanted to practice designing various types of action potential measurement circuits, so creating an action potential generating circuit was an obvious perquisite.

See the full post at SWHarden.com.

Check out the video after the break.

TTL triggered stimulus generator


Scott Harden has a nice build log on his TTL triggered stimulus generator project:

I was presented with a need to rapidly develop a pulse generator to take a TTL input and output a programmable output (for now 0.1 ms pulses at 20 Hz for as long as the input is high). I achieved this with a one-afternoon turnaround and the result looks great! This post documents the design and fabrication of this prototype device, with emphasis placed on design considerations and construction technique.

See the full post at SWHarden.com.