Author Archives: batchloaf

Set timezone to Europe/Dublin at command line in Debian Live

To list timezones: To set timezone to Europe/Dublin:

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Arduino Nano Timer 1 interrupt example for 100 Hz sampling

100 Hz sampling using Timer 1 interrupt 100 Hz sampling with moving average

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Running Arduino IDE in a Debian Live session

The Arduino IDE requires access to the serial port (/dev/ttyUSB0 on my machine) to upload a sketch to the Arduino. In a Debian Live session, the default user (“user”) doesn’t have permission to access the serial port. Possible solutions include: … Continue reading

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Installing VirtualBox on Debian 11

Install VirtualBox Note: To get VirtualBox working on my machine, I had to disable “secure boot” in the machine’s BIOS settings so that the vboxdrv kernel module could be loaded. The vboxdrv module appears to be unsigned. Go to this … Continue reading

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More PRBS turtle graphics

In this plot, four cycles of PRBS-15 are shown. Like all PRBS sequences generated using a linear feedback shift register (LFSR), this binary sequence is periodic with a period of 32767 bits. The colour of each point on the path … Continue reading

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PRBS visualisation in the style of turtle graphics

Having just watched two great Numberphile videos with Matt Henderson (1, 2), I was inspired to try visualising a PRBS in the style of turtle graphics. Below is my first quick experiment. The sequence used in this example is the … Continue reading

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Using ffmpeg to take a snapshot with a webcam in Windows

I downloaded the BtbN Windows build of ffmpeg from here: https://github.com/BtbN/FFmpeg-Builds/releases The specific file I downloaded was: ffmpeg-n4.4.1-2-gcc33e73618-win64-gpl-4.4.zip (download) I extracted the zip file, then opened a command window in the “bin” folder where ffmpeg.exe was located and took a … Continue reading

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Using a serial byte sent from an Arduino to launch an application on the PC

One of my students is building an Arduino-based robotic system that needs to run a program on the PC to do some image capture. The Python script below bridges the gap. It opens a serial port (you need to specify … Continue reading

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Generating variations on a code analysis question in a Brightspace quiz

NB This post is a work in progress. Download example files: example_question.zip This post documents the process I used to programmatically generate multiple variations on a quiz question for the Brightspace virtual learning environment. The quiz question displays an example … Continue reading

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How to merge two Garmin .fit files and upload to Strava on Ubuntu

First, install gpsbabel and (optionally) gpxviewer. Now, use gpsbabel to combine the two .fit files into a single .gpx file. gpxviewer can be used to check the merged activity on a map. The merged activity file can now be uploaded … Continue reading

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