Byron J.

Member Since: September 10, 2013

Country: United States


Apparently, the J is for JFET.

Embedded Micro's new IDE and the Lucid language.

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Thoughts and ramblings about numbers, plus an interesting discovery.

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Examining one of the categories that occupies significant space on my workbench: wire strippers.

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Drive the Moog Werkstatt-01 with the SparkPunk sequencer, and starting in on a MIDI-to-CV converter.

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Experimenting with optics and imagery.

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Rotary Switch Potentiometer Hookup Guide

April 30, 2015

How to use the Rotary Switch Potentiometer breakout board, with some sample applications.

Servo Trigger Hookup Guide

March 26, 2015

How to use the SparkFun Servo Trigger to control a vast array of Servo Motors, without any programming!

Pi Wedge B+ Hookup Guide

December 18, 2014

How to assemble and start using the Pi Wedge to prototype with the Raspberry Pi B+.

Decade Resistance Box Hookup Guide

December 4, 2014

How to assemble the decade resistance box, then use it as a design and measurement tool.

SparkPunk Sequencer Theory and Applications Guide

August 14, 2014

Examine the inner workings of the SparkPunk Sequencer, then explore some modifications and alternate applications.

SparkPunk Sequencer Hookup Guide

August 14, 2014

How to assemble and use the SparkPunk Sequencer kit.

SparkPunk Hookup Guide

June 12, 2014

How to assemble and modify the SparkPunk Sound Generator kit.

Pi Wedge Hookup Guide

May 29, 2014

How to assemble and start using the Pi Wedge to prototype with a Raspberry Pi.

Large Solderable Breadboard Hookup Guide

February 27, 2014

This breadboard has a couple of tricks up it's sleeve!

Sound Detector Hookup Guide

February 27, 2014

The Sound Detector is a microphone with a binary output. This guide explains how it works and how you can use it in your projects.

VKey Voltage Keypad Hookup Guide

February 13, 2014

A quick hookup for the VKey analog voltage keypad.
  • I’m afraid I don’t see how I misused the word. I meant “one from the last,” so that’s what I said.

  • Just be sure to match them in conjugate pairs with flop-flops.

    I’m pretty sure I’ve seen some old Japanese schematics (possibly Tascam or Roland) that indicated “frip-frops.”

  • You could build one heck of a driver for the WS2812 addressable LEDs.

  • One example that’s inspired me: Scott Gravenhorst has been making FPGA-based audio synthesizers, which seem to get updated every time Xilinx release a new dev board:


  • Uh, yeah…I’m an engineer, not a salesman.

    Article has been amended with the link - just click on the Mojo photo!

  • At the end of the day, they’re probably pretty similar. Either solution behaves about the same in the hands of the user.

    A freely-turning rotary encoder might require a display to show the current setting, and requires two digital inputs. The rotary switch requires a single analog input, but indicates the selection with just the shaft angle.

    For an Arduino project, it might come down to which approach you’re more comfortable writing the code for!

  • The board I was hinting at in my last comment just went live.

    It’s here.

    There’s also a 1-to-10 version of your concept in the hookup guide that should be easy enough to grow to two switches for 1-to-100 (well, really 0-to-99. since 100 is 3 digits long).

  • Yes, R9 bleeds the cap back to ground. If you want it to discharge more quickly, reduce either the resistor or the cap.

    If you want to play around with the sim, there are LT Spice files in the GitHub repo. “Sound_detector-wav.asc” allows you to use a .wav file as simulated input.

  • I think there are several things at play here that might be confusing things overall.

    When that hookup guide was written, I didn’t have a scope capable of capturing a diagram like that - the minimum time base was too fast to capture audio bursts like that, and I only had 2 channels. So I used an LTSPICE simulation to generate the diagram, using the output of a different simulation as a substitute for actual audio input, and adjusting the display parameters to make things line up – in the algebra in the top line, you’ll notice that the audio signal has been multiplied by 5 and offset by 2.5V. It doesn’t actually drop below 0V – it’s just been scaled to be a little more visible against the other signals.

    The signals in the picture approximate what you’d see if you put a 3 channel scope on the 3 outputs of the Sound Detector, where the audio output is indeed DC-coupled, similar to our Electret Mic Breakout. With the DC bias, it’s easier to interface with a microcontroller.

    But that’s not the signal that’s fed to the input of the rectifier - it’s AC-coupled via C4, removing the Vcc/2 offset. The 0 in the pseudocode is correct – correct for the canonical output of the rectifier – which feeds the lowpass filter of R8/C1. This lowpass obscures some of the detail in the peak-tracking behavior of the rectifier, but results in a better behaved signal at the input to the Schmitt trigger.

  • And now, having had the weekend to turn this over in my head, it sounds like it might be a great project to tackle with a Microview.