Recently I wrote about reading Si7021 temperature and humidity data using a Raspberry Pi. Now let’s try a completely different platform, the ESP32. This is essentially a project to explore using I2C on the ESP32 platform and to understand the build process.

Project layout

Since we’re developing the Si7021 interface code as a reusable component, we need to structure our project in such a way that we can easily refer to it in our main code. Here’s how I structured this project:

The Heltec WIFI Kit 32 is an interesting little module that integrates a WiFi/MCU SoC and a small OLED display on a single board. If you want to set up the Arduino IDE to work with this device and you’re on macOS, this is for you. This particular ESP32 module has a number of impressive features: 240 MHz processor speed and 4 MB of flash memory. The onboard OLED display can be conveniently used for debugging.

Brutal piece by Adam Davidson about the pivotal role that the takedown of Michael Cohen plays in the unraveling of this disastrous presidency.

The narrative that will become widely understood is that Donald Trump did not sit atop a global empire. He was not an intuitive genius and tough guy who created billions of dollars of wealth through fearlessness. He had a small, sad operation, mostly run by his two oldest children and Michael Cohen, a lousy lawyer who barely keeps up the pretenses of lawyering and who now faces an avalanche of charges, from taxicab-backed bank fraud to money laundering and campaign-finance violations.

A brutal piece on Trump from the New York Times.

There are plenty of examples these days, from Moscow to Budapest, of how “democracies” can be manipulated to the point where they can yield only one result. This is Trump’s objective, and for it he needs a weakened Justice Department, a weakened press and an American public that will believe anything. He has had setbacks but is stubborn.

Trump’s toolkit is familiar. In it are the tools of every authoritarian brute everywhere. Americans are better than this, though.

Great Stalin - banner of friendship of the peoples of the Soviet Union!

After reading about U.S. President Donald Trump’s “Number 1 fan”, Gene Huber, I was struck by the similarities between the adoration of Trump and that of Soviet leader, Josef Stalin. Throughout his tenure as General Secretary of the Communist Part of the Soviet Union, a cult of personality developed around Stalin. He was often called Великий Сталин (Great Stalin.) Propaganda posters depicted Stalin as a benevolent steward of the needs of the people.

“Спасибо любимому Сталину - за счастливое детство!”

(Thank you dear Stalin for a happy childhood.)

Rotary encoders are notoriously difficult to get right.

Although I haven’t used this new encoder class yet, it looks very interesting. From active Teensy forum user Theremingenieur, it allows initialization with upper and/or lower limits.

You can find the code in this thread.

While working on a project to automate environmental control in our greenhouse, I needed to implement a menu interface on a small OLED display. In this sub-project, meant to test the concept, I’ve used a Teensy 3.1, a small I2C-driven 0.96" monochrome OLED display and a rotary encoder.

Bill of materials:

• Teensy 3.1 - the Teensy 3.1 is no longer available, but you can easily find the compatible Teensy 3.2.
• 0.96" yellow/blue I2C OLED module - I used the version with the yellow band at the top so that it this area could act as the highlighted region of the display.
• Rotary encoder with push-button switch - I used this one from Adafruit, but there are many options.
• {% asset_link MC74HC14.pdf 74HC14 Schmitt Trigger inverter %} - to debounce the pushbutton.

Description

This project is a proof-of-concept for using a rotary encoder to manipulate an on-screen menu of options. A number of electronics design concepts are used here.

Carl Sagan’s “Baloney detection kit” is arguably more important now than ever. His 9 rules for critical thinking work for science and they can work to detect political baloney, too.

Arguments from authority carry little weight — “authorities” have made mistakes in the past. They will do so again in the future. Perhaps a better way to say it is that in science there are no authorities; at most, there are experts.