Munin is a great and easy way to monitor your servers. The documentation for Munin is kind of all over the place, and sometimes not all that clear. * There is the recent ["Munin Guide"](https://munin.readthedocs.io/en/latest/) which is quite informative and well laid out. Sometimes additional info and …

The default serial speed on the ESP8266 WiFi chip is 115200 baud. If you connect this chip to an Arduino and want to use SoftSerial to talk to it, it will not work. The SoftSerial library is limited to 9600 baud because of hardware limitations of the Arduino. If you want to talk to the ESP8266 with an Arduino at lower …

If you used DSA keys to log in to your SSH server and have upgraded your client machine to macOS Sierra (or OSX Sierra if you like), you probably ran into this problem: [sourcecode language="text" gutter="false"] client$ ssh -p 8123 george@10.0.0.10 -i ~/.ssh/id_dsa Permission denied (publickey). …

Many years ago, I used to do some radio fox hunting with cars. Usually these hunts are at night to make it more exciting, and can be great fun. As I got older I lost interest and moved on to other things. But last year, I decided to have a go at a popular balloon fox hunt on 144MHz. This is quite a large scale and …

If you are using JAXB in a maven/java project to unmarshal an XML document and you get: javax.xml.bind.UnmarshalException: unexpected element (uri:"urn:iso:std:somestuff:xsd:somestuff", local:"Document"). Expected elements are (none) Or if you are using JAXB to marshal an XML document and you get: …

When doing integration testing or fixing a bug in a piece of Java code that uses Oracle as a database, being able to do quick exports and imports of your schema can be a big help. Sometimes just calling Oracle's imp/exp commandline tools from your code can be of help, but I was looking for something a bit more portable …

I recently needed to print out a big schematic diagram of the RX/TX board of a Kenwood TS50 Transceiver. This did not fit on a single piece of paper. Instead of downloading all kinds of crappy tools or uploading the image to some "free" site which is going to use it for whatever they think justifies their …

Regular readers of this blog already know that I am not using dropbox, and I was an Evernote user, but recently decided it became to dangerous and replaced it with my own scripts. I had an interesting discussion on Twitter which made me decide to show you how I run my digital life without the help of Google, Facebook, …

A quick tip for OSX users out there who frequently need to open a Terminal window for the current location in the finder, or the other way around: Install the free application from the App Store: Go2Shell. It will give you an icon on the toolbar of your Finder, and pressing it will open a Terminal window and …