Teensy, touch sensing, and ESP8266 – via MQTT and Raspberry Pi

Posted on by CBMalloch

Whee!

I have a demo/development setup on a small breadboard which powers an ESP-01 ( the small, cheap, 8-pin breakout board for an ESP8266 chip ). In addition to being a programming board, it has 3v3 voltage regulation, a pot, a temperature sensor, a simple LED, and a WS2812 3-color LED. I have the installed ESP8266 running a program to subscribe to an MQTT broker and light the LEDs according to publications on a certain topic.

[Read More...]

Securing a Raspberry Pi IoT Gateway

Posted on by CBMalloch

I believe that the UMass IT policy forbids “rogue” WiFi gateways in order to prevent anonymous Internet access, so that nefarious actors can be identified.

I needed to create an IoT server for my lab, M5, and it needed to be accessible via WiFi. It also needed to have Internet access so that I could keep its Linux firmware up to date.

[Read More...]

Calculating the Axis of Nutation of my Solar Tracker

Posted on by CBMalloch

Following on the cluster analysis of the last post, I pairwise crossed (as in cross-multiply) the resulting cluster centers, and got three reasonably-close vectors after normalization. These were:

0 x 1: (-0.36, 0.93, -0.10)
0 x 2: (-0.23, 0.97, -0.06)
1 x 2: (-0.20, 0.97, -0.14)

While satisfyingly close, I wanted to do better.

[Read More...]

Instrumenting and Analyzing My Solar Tracker

Posted on by CBMalloch

I’m an instrumentation and data collection geek. I love the challenge of developing ways to monitor the systems of my house and making sure they’re working properly. I’ve had a couple bad experiences where systems failed and not knowing it soon enough caused problems.

[Read More...]

Quaternions are fun!

Posted on by CBMalloch

Once upon a time, I was a math major. I shunned engineering as not pure enough — I wanted to be a scientist. And I didn’t see that most of the really good mathematics is developed in support of other sciences, particularly physics, and engineering. Fourier analysis. Eigenfunctions. Complex numbers. And linear algebra.

[Read More...]

The overloading of potentiometers

Posted on by CBMalloch

Creating complex firmware for existing hardware is often complicated by unforseen ( or ignored by the hardware designer ) human-interface issues. One example of this situation comes up when a project requires more settings than there are physical controls for. Modern cameras provide examples of the problem, and also of its solution.

[Read More...]