Author Archives: Jim

Recording preamp: new plan, better than ever!

Posted on November 6, 2011 by Jim

Wow – the little Sansa recorders have caused significant changes and clarifications to the plan for my square dance recorders.  I’m going to end up with almost everything I’ve asked for.  The new plan: The only supported recorder will be … Continue reading →

Posted in Recording preamp/limiter | 1 Comment

What a difference 30 years makes!

Posted on November 2, 2011 by Jim

While I was testing the latest version of the recording preamp, I needed a simple audio amp.  A good old LM386 would be fine.  I’ve been making stuff on printed circuit boards and vector boards for quite a while, and … Continue reading →

Posted in PCB Etching, Recording preamp/limiter | 1 Comment

Rebuilding my Pogoplug house monitor server

Posted on October 4, 2011 by Jim

Ya know, you’d think there would never be a situation when anybody would accidentally enter the following 2 commands in order: # cd / # rm -rf * That’s what I thought, too, until I just did it today.  Below … Continue reading →

Posted in Home Automation | 4 Comments

Sansa Clip+ recorder external input hack

Posted on September 17, 2011 by Jim

Here’s (one of) my shiny new $20 4 GB Sansa Clip+ MP3 recorder/players from Woot.  It’s smaller than I’d pictured – but that’s fine.  The little “R” melted into the back of the clip might well mark it as refurbished, … Continue reading →

Posted in Recording preamp/limiter | 7 Comments

New PCB etch exposure stuff

Posted on September 13, 2011 by Jim

While my dear old 18″ UV fluorescent tube setup for exposing sensitized PCBs works fine, it’s pretty clunky.  I found a 13W black light CFL bulb and thought it might make a more convenient setup.  Since the manufacturer says the … Continue reading →

Posted in PCB Etching | Leave a comment

Etching board holder

Posted on September 13, 2011 by Jim

I needed a better device to hold boards while in the CuCl2 bubble etcher.  The plastic shipping holders from the coffee packet system (Flavia) we use at work looked like they might be useful someday, so over the past year … Continue reading →

Posted in Cupric Chloride Etchant, PCB Etching | Leave a comment

Root hacking

Posted on September 12, 2011 by Jim

There’s a big chunk of exposed tree root that rises above ground level enough that I’m afraid the mover is going to hit it every time I mow.  I finally cut it down a bunch. The original plan was to … Continue reading →

Posted in Home Repair | 1 Comment

Recording preamp/limiter – with battery test

Posted on August 30, 2011 by Jim

(Post rebuilt – see footnote.) I’ve built several preamp/AGC/limiter boxes for square dance recording, each getting a little better than the last. (Well, the black one wasn’t so great.) I still aspire to a “perfect” device, answering all my needs. … Continue reading →

Posted in Recording preamp/limiter | Leave a comment

Old Palm as serial terminal

Posted on August 29, 2011 by Jim

As I started setting up to use ATTiny85s with Arduino IDE and ArduinoISP as programmer, I quickly came across the “How do I get debug output?” question.  While the chip doesn’t have a UART, there is a Tiny Debug Serial … Continue reading →

Posted in Palm Serial Terminal | 3 Comments

Sump pump current sensor

Posted on August 9, 2011 by Jim

This sensor has been part of the home automation system for several years.  It’s mounted to the wall, and the main AC sump pump is plugged into it.  It senses current to the pump, converting it to a logic level … Continue reading →

Posted in Home Automation | 5 Comments