JamesL

Dim Bulb Tester

WARNING: This post involves live mains electricity and is EXTREMELY DANGEROUS! Do not attempt this project on your own unless you are qualified to do so. I advise you to engage a licensed electrician to help you build this test unit! Most of my electronics projects involve modern devices that require low voltage DC and …

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Asterisk on AWS Linux

A couple of months ago I decided to move my company’s Asterisk PBX system from one of our physical data-center servers to Amazon’s AWS EC2 Platform. We had been using Trixbox since 2006, but the Community Edition of that product (Trixbox CE) is no longer being developed and is no longer supported. Since I was …

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How To Properly Test Batteries

Testing batteries seems like an overly simple topic for a blog post, but unless you have a good quality battery tester, then chances are you’re not testing your batteries correctly. When testing with a multimeter, most people will simply take an open circuit voltage measurement from their cell. The problem with this approach is that …

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Detecting Failed AD2USB to Raspberry Pi Connections

One of my ongoing home automation frustrations is the interface between my Ademco Alarm Panel and the Raspberry Pi I use to monitor the panel’s bus traffic. The problem that I have is a termination of the USB connection between the AD2USB (AlarmDecoder) that taps into the Ademco panel and the Pi itself. This always …

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EC2, UFW and Broken SSH Access

I’m a big fan of Amazon’s EC2 platform and long ago migrated all of my servers to its “cloud”. I’m also a realist when it comes to security and take all of the reasonable precautions I can to limit my risks. One such precaution is two-factor authentication for SSH (see my article “Two-Factor Authentication System …

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