Blog | JackGruber

Embed Mermaid in Jekyll without plugin

Posted on May 9, 2021

Mermaid is a simple markdown-like script language for generating charts from text via javascript. I would like to show you how you can enable rendering of mermaid diagrams without plugin in your Jekyll blog/site which is useful for Github pages. [Read More]
Tags:
- Jekyll
- Mermaid
- Github
- howto
From Evernote to Joplin

Posted on December 30, 2020

For the past year, I’ve been using Joplin for my note management. Previously, I had used Evernote for years, but wanted to get away from it, because all notes stored in the cloud. [Read More]
Tags:
- Evernote
- Joplin
- Cloud
- Workflow
ESP32 battery/solar powerd environmental sensor

Posted on December 27, 2020

This year I tinkered with an environmental sensor, which should be solar powered and transmit the readings via LoraWAN (thethingsnetwork). [Read More]
Tags:
- ESP32
- LoraWAN
- TTN
- PCB
- DIY
- Solar
Making an APC Back UPS CS500 smart

Posted on October 16, 2020

I still have an APC Back-UPS CS500 which protects my Synology, Rasperry PI and co. Since it’s not network-capable and only has “Simple Signalling”, I want to do this with an ESP8266 smart. [Read More]
Tags:
- ESP8266
- IoT
- APC
- UPS
- MQTT
- Tasmota
Own syncserver with Firefox 80 (79 on Android)

Posted on August 29, 2020

Since the Firefox update to version 80 and 79 on android a few things have changed to be able to use your own syncserver as described in the blog post Setup your own Firefox Sync Server with Docker. [Read More]
Tags:
- firefox
- howto
- cloud
Docker monitoring

with Grafana, prometheus, cadvisor and exporter

Posted on August 15, 2020

[Read More]
Tags:
- Docker
- Grafana
- Monitoring
- Raspberry Pi
- HowTo
ESP32 DeepSleep and LoraWAN OTAA join

Posted on April 13, 2020

When the ESP32 goes into DeepSleep and wake up, it will not restart the code execution from where it entered DeepSleep, like an ATmega witch restarts code execution at the same place including all set variables. The ESP32 starts in the Setup function an reinitializes all variables, this means that... [Read More]
Tags:
- ESP32
- LoraWAN
- Arduino
- µC
- LMIC
- TTN
Low power Arduino Pro Mini

Posted on December 27, 2019

For various projects where a long runtime with batteries is important I use a modify Arduino Pro Mini 328 3.3V/8Mhz (ATmega328P). As an example a flashing sketch is used, which turns the LED on for 1 second and off for 8 seconds. [Read More]
Tags:
- howto
- hack
- Arduino
- µC
- Hardware
gnupg cannot connect to keyserver

keyserver receive failed: Connection refused

Posted on June 7, 2019

On a docker project where i had to add gnupg keys i always got an error keyserver receive failed: Connection refused. After a while of troubleshooting, i realized it’s not a connection or DNS problem. But that the Dirmngr did not use the configured DNS servers of the system. gpg... [Read More]
Tags:
Security hardware key on Github with Firefox

Spoof User Agent in Firefox

Posted on June 7, 2019

Github currently supports hardware security keys (SoloKeys, Yubico, …) as second factor only with Google Chrome but not with Firefox, although Firefox supports U2F and on other sites this also works flawlessly. This browser doesn’t support the FIDO U2F standard yet. [Read More]
Tags:
- howto
- firefox
- U2F
- SoloKeys
- security
- FIDO U2F
- 2FA