my recent reads..

LEAP#376 Piezo Vibration Detector and BPM Counter

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 hero_image


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LEAP#374 LT1019 Voltage Reference

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 hero_image


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cracking the static site SSL challenge with netlify

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.

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… 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!


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LEAP#371 common emitter amplifier biasing

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 hero_image


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