Diary of an Emacs tragic

Month: April 2014

increase wordpress Maximum upload file size beyond 8MB.

There is at least three places you need to set the maximum upload file size in WordPress.
First check your php.ini
upload_max_filesize = 64M; post_max_size = 64M;
Restart Apache after making this change.
Then if you are using WordPress multi-site, you need change a setting in the backend. Visit My Sites -> Network Admin -> Dashboard -> Settings -> Network Settings. Then scroll down to the Upload Settings area and change that.
Thanks to dorr13 for that tip.

29/04/2014
How to create debian init.d startup script

From time to time I need to create an init.d startup script for a program that is not part of the default debian distribution. I’ve always found it unnecessarily fiddly to create a new script. The other day I came across naholyr’s gist, a script to make init.d scripts.
There were a few problems with it so I made it into a proper github project and fixed up the problems. The url it was retrieving the service.sh script from was 404, and it wasn’t checking for successful download of the script, so I made it abort if it fails to download.
I couldn’t come up with a decent name for it so its called sample-service-script.
I already had a few pull request to it, yay!

29/04/2014
Progress on my clock

I finally wired up the big LEDs and made an acrylic mounting board for all the parts. I laser cut holes in the board and tapped them with an M3 tap. That allowed me to mount the circuit boards directly to the mounting board. I used Dupont connectors to wire everything up which gives a very neat finish I think.

24/04/2014
How to factory reset a Yealink phone

If you ever need to do a factory reset on a Yealink phone, maybe if you forgot the admin password, simply hold the OK key down for 10 seconds and follow the prompts.
Thanks to Langineers for that tip.

18/04/2014
Set group permissions for whole subdirectory with ACLs

Sometimes you want to preserve file permissions under subdirectories in linux with ACLs but that’s not the whole story. If you want multiple users to be able to read and write to these files, and the group permissions to stay correct, you need to set ACLs and also group +s on the subdirectories. This is to ensure new files and directories are also created with the correct permissions and group ownership.
I wrote a small script that takes a group and a directory as parameters, and recursively fixes the permissions and set new ACL and group permissions so in future, new files will have the correct permissions.
I put set-acl-permissions on github.
It blindly recursively sets permissions so be careful. Also, it may well contain bugs that could cause catastrophic failures.

18/04/2014
LED Clock Project
For a long time I have wanted a bedside clock that would keep accurate time via some external mechanism, and would take care of daylight savings automatically. I eventually decided that the best approach would be to use a wifi enabled device and use the NTP protocol for keeping the time accurate.
After wasting several months hacking away on an Olimex IMX 233 that never worked reliably, I decided to change platform to the Beaglebone Black (BBB).
Along the way I realised there were a few other features I needed:
- LEDs should dim with the ambient light so the clock doesn’t light up the whole bedroom
- The display needs to be big enough for me to read from across the bedroom without my glasses on.
  To make them dimmable I decided to get a pair of
  I also needed a power supply that could give 12v for the LED drivers but 5v for the BBB. I found a nice little board on ebay for a few bucks that seems to do the trick. Its called the Benq 12v-5v-3.3v
  I hooked that up tonight so now I only need the one power supply to run the LEDs and the BBB.
15/04/2014
My uranium mug is not radioactive

A while ago I broke my favourite mug. After a long and difficult search I found a new mug. A mug with the periodic table of elements entry for uranium on it. It also glows in the dark. Gav from the hacker space has a Geiger counter so I took the opportunity to measure the radioactivity of my mug. Luckily it’s not radioactive at all. Only 0.106μSv/h (micro Sieverts per hour).

09/04/2014
Pull a backup from a remote host with ssh and tar
Sometimes you might need to copy a whole directory from a remote host, but the remote host does not have enough space to tar the whole thing up and then sftp it off. The solution is to tar/bzip the directory and stream it directly to your local host:
```
ssh root@remotehost 'tar cjf - /path/to/somedirectory' | pv -cN tar  > somedirectory.tar.bz2
```
Using pv (pipe viewer) gives you extra progress bar goodness:
```
tar:  176MB 0:09:14 [ 371kB/s] [                             <=>    ]
```
07/04/2014
HP MediaSmart IR Remote for MythTV
I’ve been on a quest to find a good remote for MythTV. My first try was with a Logitech Harmony. Those things are nasty horrible pieces of crap. I’d never touch one again. Programming it is a nightmare. It does not have a generic PVR option so you have to fake it to make it work with Mythtv by telling it its another device and learning those codes in LIRC. It is a very slow device with what felt like a 500ms delay with each keypress. It also tried to know what state your equipment was in so that it could turn things on and off, but of course it would always be out of sync and then you’d have to go through this process of turning things on and off until it was in sync again.
Enter the HP MediaSmart IR remote, also known as HP RC2285202/01. These devices used come with a media player box that HP used to sell. As far as I can tell, its not in production anymore but the remotes are readily available on Ebay.
Features:
1. Dedicated IR codes for the PVR. On previous universal remotes I have used, I was unable to find a “code” setting that would make all the buttons active, that I could then learn in LIRC.
2. Back-lit keys. All the keys seem to be backlit. Some universal remotes either only backlight a few keys or have no backlight at all.
3. Cheap. A$23 with USB receiver, delivered.
4. Universal remote. Can control 5 devices including your PVR.
5. Punch Through. Some buttons like volume and mute can punch through from the TV or Amp, to the PVR device. IE. you can make it turn the volume up on the amp when you press the volume button when in PVR or TV modes.
6. Takes standard AA batteries.
There are a few downsides too:
1. Difficult to get going (solved now that you have found this blog post)
2. Punch through does not work on all buttons. Namely Power and Source. This is annoying but solvable with a pulse-eight CEC adapter
I spent many hours trying to work out why it would not work on my system. In the end it came down to two things.
For some reason LIRC does not work correctly with MCEUSB receivers that are plugged into USB3 sockets.
You need to tell the kernel to treat the receiver as lirc rather than anything else, in order for LIRC to be able to connect to it:
```
$ sudo sh -c "echo lirc > /sys/class/rc/rc6/protocols"
$ sudo cat /sys/class/rc/rc6/protocols
rc-5 nec rc-6 jvc sony mce_kbd [lirc]
```
The word [lirc] surrounded with square brackets tells you it worked.
I implemented this at boot time by adding
```
/etc/rc-scripts/start-lirc
```
to /etc/rc.local and then in /etc/rc-scripts/start-lirc
```
#!/bin/bash
echo "Making lirc the default for rc"
echo lirc > /sys/class/rc/rc0/protocols
echo "Starting lircd"
/etc/init.d/lirc start
```
Remove lirc from the normal startup process:
```
$ sudo update-rc.d lirc remove
```
Test your configuration (retrieve HP-RC2285301-01.conf below):
```
$ sudo /usr/sbin/lircd -n -d /dev/lirc0 -P ./lirc.pid  HP-RC2285201-01.conf
$ irw
```
And when you press the keys on your remote, you should see some output from irw.
03/04/2014