Tag Archive for Raspberry Pi

Getting temperature from Raspberry Pi

I am currently developing some code for sensors to use with my Raspberry Pi, it came to my interest to get some temperature data from the Pi, a quick search give me a very good result.

Actually there are temperature sensors on the Pi

/opt/vc/bin/vcgencmd measure_temp

Added to cronjob
/opt/vc/bin/vcgencmd measure_temp >> ~/rpi_temp.log

This will append data to the log file.

Overclocking – Raspberry Pi User Forum

TV Streaming and playback on Raspberry Pi

Follow by previous post on the MPEG2 license MPEG2 hardware decode license for Raspberry Pi., I get my hands busy putting things together to make use of the Pi.

The above screenshot is about streaming local TV signal in H.K. from Pi to network.

A bit of explanation:


  • Raspberry Pi version B running on 900MHz
  • A USB 2.0 Hub with external power supply.
  • MyGica D689 USB DVB-TH TV Tuner


  • mumudvb for streaming TV signal to the network
  • omxplayer for local playback
  • vlc on win32 for playback on PC (remote)

With the new MPEG2 License, playback on RPi with omxplayer is takes about 23% CPU,
mumudvb streaming to 2 IP unicast with different TV channel takes about 33% CPU,

With the new MPEG2 hardware decode license, it plays back at 100% frame rate on the Pi (was like 3fps only without the license)

P.S: I am having sound issues on my Pi due to some other reasons, didn’t spend the time on fixing it yet, so now local playback at mute, but I am sure I can iron it out next (should related to some ALSA drivers issues)

Good one there Team Raspberry Pi, such a nice computer to have and play with, thanks!

MPEG2 hardware decode license for Raspberry Pi.

It is just great for developers / manufacturers to listen to how the user thinks and use their products.

A Few word from the officials

If you’ve been following this website since we launched it last summer, you’ll probably be aware that we had to make some hard decisions about exactly what we could include on the Raspberry Pi if we were to meet our extremely low target price. One of the things that we had to regretfully dismiss as an option was an MPEG-2 decode licence for every unit. Providing that licence would have raised the price of every Raspberry Pi by roughly 10%, and we simply weren’t able to justify that when we held it up against the educational goals of the Foundation. Our initial expectation was that most of you would buy the Raspberry Pi for educational purposes, and that you wouldn’t mind that MPEG-2 wasn’t available. Our bad.

At GBP2.4 (only USD3.8, or HKD30), now our beloved RaspberryPi can enjoy full hardware decode with MPEG2 support, which is very important for my usage in DVB TV solutions!

New video features! MPEG-2 and VC-1 decode, H.264 encode, CEC support – http://www.raspberrypi.org/archives/1839

Place your order now to show support! I ordered mine~~~

MPEG-2 license key http://www.raspberrypi.com/mpeg-2-license-key/

1525: Order placed, confirmation received.
1712: License Key received.

That is quick!

Seems I will need to upgrade firmware of GPU / recompile my custom kernel for the new MPEG2 decode to work (at least August 8th or newer releases based on post #1883) and I am a bit busy to do so, I shall leave it for the mean time till I am a bit more free to do so…
Raspberry Pi Discussion Forum – You wanted MPEG-2? You’ve got it!

ARMania – my ARM based devices.

Recently I have obtained different ARM based hardware for different usage / reasons, it always interested at these boards for different usages, and recently thanks to mates and friends, I have the chance and time to finally put some effort to it to do what I want.

Here are a few idea I would like to make use of these board.

  1.  A DVB-TH streaming server.
      I do own a slingbox, but the idea of a native app + extra cost on every client + the price of the slingbox isn’t something that interested me, what I would like to do is a HTML5 based DVB-TH streaming service, which I can stream DVB content to my devices in browser with HTML5.
  2. A home server monitor system.
      I recently am into Arduino, I would like to build a Web base sensors, video, sound system with it, which I can log example temperature, noise level, and some basic home automation with it.
  3. A old console emulator.
      I have been wanted to do this for long, who doesn’t love to play Mario Brothers now??

I have a different sets of devices on hand to do all of the above, but which goes which and which does the best?

Android device MK802

1200MHz CPU 1000MB RAM

This is an Android device which also support Ubuntu Linux 12.04 from the TF Card slot, honest currently it is very limited early build, I did try to run a few console emulator on Android port, too bad the speed wasn’t really up to my standard (<30fps), and there isn’t a big difference (A bit better) for emulators on Linux port, maybe due to lack of OpenGL and poor GFX drivers, I do have higher hope on this device since its higher CPU clock speed and more memory, I suggest it should get better when a better build of Android / Linux is being developed.


Raspberry Pi

ARM1176JZF-S 700 MHz CPU 256MB RAM

Just got it today in the morning, I think I will try idea 1 and 3.

TP-Link WR703N

Atheros AR7240 CPU (400Mhz) 32MB RAM

This device was meant to be a wireless router with a USB port, with custom firmware thanks to team openwrt, I was able to get basic DVB-TH streaming by mumudvb (no transcoding due to limited CPU resources and memory) with a custom build of openwrt, and I think this should be prefect for my idea 3, A home server system with Arduinos, USB webcam and so on because of its low power consuming.

The hard part on getting work done on WR703N was the OS, openwrt is not full linux, and I do have to go all way round to compile the whole build in order to get extra drivers and app support, compare to the above 2 which many apps / solutions has already been done and ready to use by apt-get install.

With all current test, to my surprise which turns out the old console emulation was the part which all these 3 devices didn’t handle that well (which mainly because poor GFX and CPU processing power and drivers support), and if transcoding is needed on DVB streaming, more processing power shall be needed, which leaves me to think of fall back to ATOM base x86 solutions.