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Category: Hardware

New RTL-SDR gear

Frederik Granna 1 Comment

I’ve played with these RTL-SDR sticks for several years now and I am still amazed about the possibilities I have with these cheap pieces of hardware. I managed to receive several data modes like ADS-B, ACARS, AIS and the wireless outdoor thermometer of my neighbor – I’ll write several follow-up posts on this topics 🙂

I decided to get two new Sticks for my collection – this time with a TCXO oscillator to get a more stable reception.

Modified Stick? Whats the deal?

Shift over time (source: rtl-sdr.com)
Shift over time (source: rtl-sdr.com)

A common problem for these sticks is frequency stability over time. As the oscillator is heating up under load, the frequency of the crystal measured in ppm (parts per million) will change – which causes the frequency to shift. Typical values for cheap sticks are +-150ppm. The real amount of frequency should could be several kHz, which make this behaviour really annoying for headless receivers (like ADSB receivers on a Raspberry Pi) – especially if you try to receive a narrow signal.

 

 

 

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Docker on a Raspberry Pi

Frederik Granna 1 Comment

The guys at Hypriot did an awesome job to bring Docker to the Raspberry Pi world.

If you want to give it a try, you have two options

Option 1: Prebuilt images

Thats the best option if you want to have a full-fledged docker environment with optimized settings and hassle free installation.

Just download the image from this page and “burn” it to a sd-card. Plug the card in your RPi and enjoy.

Read more about this solution in their Blog: Get your all-in-one Docker playground now: HypriotOS reloaded!

Option 2: Debian Package

This option is the way you should go if you don’t have a spare sd-card around.

You can download a .dep file from this page and install it via dpkg -i package_name.deb

I tried this option on my current Jessie installation and encountered one problem: All docker command had to be issued via sudo. Thats because the docker.sock is only accessible for the root user. I didn’t follow up on this as i am going with option one 🙂

 

Quick test run? Here we go

After you have installed either the image version or the dep, you should be good to go for a first test.

Log in to your pi and kick of the following command:

docker run -d -p 8080:80 hypriot/rpi-busybox-httpd

Docker is now downloading the webserver image from the docker registry and start the container.

Now start your web browser and open http://<your-pi-ip>:8080

hyprion test docker images

 

Wait, there is one more thing

They also build an awesome hardware stack called “The Pi Tower” which consists of 4 Raspberry Pi 2 stacked on top of a 5-Port-Switch.

(c) 2015 hypriot
Pi Tower – (c) 2015 hypriot

Read more about this at their blog: Let Docker Swarm all over your Raspberry Pi Cluster

 

Downloads: http://blog.hypriot.com/downloads/