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tardate 2018



This blog is my occasional diary of Quite Interesting Things. It is generally technical, meaning all things web, open source, polyglot-programming, electronics and concerning data. But sometimes ravings on books or musics, and occasionally a rant or philo



 



LEAP#379 AS3935 Lightning Sensor

Thu, 12 Apr 2018 13:36:30 +0000

I first heard about the AMS AS3935 Franklin Lightning Sensor in Arduino for Ham Radio. They are available as modules with built-in tuned antenna, but are relatively expensive/rare. I finally got my hands on one to experiment with.

Since we have between 171 and 186 lightning days on average a year here in Singapore, with each square kilometer being struck up to 16 times annually, I’m expecting to have some fun with this.

Here’s a first step - exploring the programming of the module with the standard Wire library. So far so good!

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub (image)




LEAP#378 BJT Phase Splitter

Sun, 11 Feb 2018 14:26:08 +0000

Simple unity-gain phase splitter in a little breadboard-compatible package. It uses a common-emmiter amplifier with a gain of -1.

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub (image)




LEAP#377 DIY Nokia 5110 Shield

Sun, 11 Feb 2018 09:05:48 +0000

Wiring it up a Nokia 5110 display every time I want a little LCD output is getting a bit tiresome. I have a spare prototyping shield, so A + B = a handy thing to have lying around for the next time.

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub (image)




LEAP#376 Piezo Vibration Detector and BPM Counter

Sun, 04 Feb 2018 14:09:16 +0000

I’m experimenting with some piezo transducers (sensors) to capture physical taps as a beats per minute measure with a microprocessor. All the filtering and debouncing of the raw piezo signal is done onboard the ATmega328 using a combination of:

  • analog comparator interrupts
  • filtering based on musical assumptions
  • exponential averaging

The result is a BPM between the threshold of the perceptual present and too fast to be useful.

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub (image)




LEAP#374 LT1019 Voltage Reference

Tue, 30 Jan 2018 11:22:40 +0000

I’ve been seeing the LT1019 precision reference show up in a number of designs recently, often as a reference for an ADC such as the LTC2400. It is worth a closer look. In this example, I’m using the LT1019 as an external analog reference for an Arduino.

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub (image)




cracking the static site SSL challenge with netlify

Mon, 22 Jan 2018 16:39:37 +0000

For the last year or so I’ve been running this blog on Github with Jekyll and Github Pages. That’s nice and easy, but the lack of SSL support for custom domains has remained stubbornly over-the-horizon.

I’m glad I tweeted my wish! With a nudge from @spencerbgibb I got to try out netlify.

(image)

… and it is the real deal! I’ve just ported half a dozen sites from Github Pages, now all with automatically-provisioned SSL from LetsEncrypt

I’m really impressed with the static-site publishing system they’ve put together. It works just like Github Pages .. but better. Seriously, all I had to do was:

  • Sign-in/sign-up
  • Choose to add a site from one of my repos (automated with GitHub OAuth)
  • Build requirements for most of these sites were auto-detected (I had a to tweak a couple where the site target was ambiguous)
  • …and the site is deployed
  • Next, add a custom domain name
  • Switch the CNAME records

Then the only time consuming bit … waiting for DNS propagation!

Once DNS is all good, enabling SSL is just three clicks: verify DNS .. do it! .. confirm!




LEAP#371 common emitter amplifier biasing

Thu, 11 Jan 2018 16:09:24 +0000

I am inspired once again by one of w2aew’s excellent vidoes, this time to revisit the operating classes and biasing design rules of the common-emitter amplifier.

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub (image)




LEAP#370 TS3A5018 Digital Switch

Mon, 08 Jan 2018 18:18:14 +0000

Just a quick test of the TS3A5018 digital switch which I am looking at for an application in switching amplifier gain stages.

The TS3A5018 is a 1.8 to 3.6V device with four SPDT switches controlled from a single input, and a master active-low enable pin. It is guaranteed break-before-make (max 58ns).

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub

(image)




LEAP#369 my beeping Boldport ananas

Sun, 07 Jan 2018 12:01:27 +0000

Boldport Club Project #20 is the first designed by Ben, the new Boldporter. And it’s a beauty!

As is often the case, a small but interesting circuit is at the core of a beautiful design. The circuit is essentially four repetitions of an RC phase-shift oscillator. Like other projects such as the famous Cordwood series, the design employs multi-board symmetry and 3D construction.

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub

(image)

Here’s a quick demo (with special customisation!):

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LEAP#368 Granular Synth

Sat, 06 Jan 2018 10:07:32 +0000

The “Granular Synth” idea harks back to an old Auduino project. I stumbled upon it again recently and decided it deserved a quick build in an Altoids tin ..

.. because granular synthesis is a basically how they make Altoids, right?

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub

(image)

If you can put up with 5 minutes of me fiddling around, here’s a taste of how it performs..

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