A clock thingy 🕰

01/07/2020

Using a Raspberry Pi and a small e-paper display, I made a thing that shows the approximate time, sunrise and sunset times, and the current weather.

The e-paper display has two colors: black and red. This also means it takes much longer to refresh than other e-paper displays.

rendering of the epaper display content

The red arc represents daytime and black the nighttime. A litle python program fetches the sunrise and sunset times and the current weather from the free openweathermap api and puts together two little images. One for the black pixels and one for the red pixels. These images are then combined and shown on the display. The vertical position of the clock changes with time to prevent a burn-in.

A Systemd timer runs the python script 3 times per hour:

# /etc/systemd/system/clock.service

[Unit]
Description=brunos clock thingy

[Service]
Type=oneshot
WorkingDirectory=/home/pi/clock
ExecStart=/usr/bin/env python3 main.py
# /etc/systemd/system/clock.timer

[Unit]
Description=timer for brunos clock thingy

[Timer]
OnCalendar=*:10,30,50

[Install]
WantedBy=timers.target

Et voilà!

Snips voice assistant

30/09/2019

Running a Snips voice assistant on a Raspberry Pi 3+, using the Seeed starter kit. Trying to programm skills for it now.

09/07/2020

The Snips console was discontinued since the aquisition of Snips by Sonos. 😕

DIY Smart Power Outlet

Eight 240 Volt power outlets individually controllable via HTTP. Uses an ESP8266 MCU with WiFi with a 8-Relay-Module. Firmware in C++. Laser-cut acrylic case designed with Sketchup and LibreCAD.

Pictures

I will update this when I have time to finish the project.

20/08/2019

It's working now. Next time I won't use acrylic, it breaks too easily. I had to use tape to prevent some parts from breaking from the pressure of the cables inside.

Enviromental data logger

I run a couple of microcontrollers that log pollution and climate data in my room and outside the apartment. They just post the data to Thingspeak. I use the cheap Lolin NodeMCU v3 (ESP8266).

The gathered pollution data is fed into this map maintained by luftdaten.info.

Web app light switch

Completely impractical React web app that with a Raspberry Pi Nodejs backend that forwards requests to a cheap four outlet power relay with http server. That chinese made power relay drove me crazy with its non-standard url encoding! Use my phone to control the bedside lamp when I could just reach over and use a switch.

WG-O-Mat

In a futile effort to get everybody in my shared flat to do their chores, I made a web app where one can log the chores they did, and collect points for it. There are many iterations and do-overs of it, some of which were used for a while. It's how I got into Javascript!