Dogear - My Cricut Woes

My Dogear project is software that I use to create one-of-a-kind generative art bookmarks. You can read about the whole project at Dogear Bookmarks

The project centered around the Cricut where I used it as a pen plotter, and a precise drag knife to cut my algorithmic designs. I wrote software to generate 130 unique bookmarks.

The hardware seems well made, and conceptually it’s a fantastic tool that was central to my ability to carry out the project. However, the software that comes with it is terrible, and treats you like a revenue stream. I’d like to tell you about all the ways I found that the Cricut Design Studio is bad.

Dogear - The Algorithmic Bookmark Project

My Dogear project is software that I use to create one-of-a-kind generative art bookmarks. Every edition of a book gets its own unique design, like a fingerprint. The bookmark belongs to the book as much as the book belongs to you.

Front and back of two bookmarks as an example:

I absolutely love how this project has turned out, but along the way I learned to dislike the Cricut Design Studio software greatly - and you can read about my Cricut Woes in a companion post to this one.

AHT20 update, and my open source experience

It’s been more than two years since I released my AHT20-driver (a Rust driver for a temperature and humidity sensor). I’ve had a lot of support and friendly interactions as a result, and I’d like to highlight what a pleasant experience it’s been.

The AHT20 sensor is a temperature and humidity sensor by the company Asair. I used the Adafruit AHT20 board during development. The driver is written in Rust, which I’ve come to really enjoy programming in.

AHT20 thermometer driver

I wrote a new driver for the AHT20 temperature and humidity sensor in Rust. This is a continuation of my Barometer build article, where I re-use the lps25_pressure_sensor_demo project to add a temperature sensor on the with_aht20_sensor branch.

I’m a complete novice at Rust and embedded programming. These projects are my attempts to learn more about both while having fun and making something useful.

You can find the driver at:

Barometer build

I put together a barometer, built around Adafruit’s LPS25 breakout board, the Blue Pill microcontroller, and a small 16x2 character LCD panel. It was a learning project, and all of it was written in Rust.

The finished project is a tangle of wires on a breadboard, and the error handling is minimal, but I definitely have a barometer with an LCD readout.

You can get the code in my lps25_pressure_sensor_demo github repo.

Ear defender headphone build

I work in a very noisy open plan office, which makes it hard to focus. To solve the problem, and still let me listen to some music, I made these noise blocking headphones. They’re built from heavy-duty Peltor ear defenders, usually worn in industrial settings to block harmful noise levels from damaging your hearing.

I’d like to show you how I made them, so that you can do the same. Here’s a picture of what they look like:

Exponential smoothing in Python

The problem

While measuring temperature using my Arduino and a TMP36, I found that the temperature reading fluctuated wildly. After reading up a little, it became clear that since the Arduino’s analog pin measures discrete values of 0-1023, and the voltage varies between 0-5V, the smallest difference that can be detected is ca. 4.9mV. For the TMP36, a temperature change of 1°C triggers a voltage change of 10mV, so the smallest temperature increment that can be registered is ±0.5°C. For additional fun, the sensor is only accurate to ±2°C, so plenty of opportunities for sensor fluctuations.