As I couldn’t find any information on the web about the heat generated by the new Wouxun KG-UV8D in cross-band repeater mode, I thought I’ll share the information with my precious readers. :)
So, if you use both bands in the low output power (0.5W) mode, the radio gets very hot in about 10 minutes of continuous repeating, but not so much that you can’t touch it – so it works fine.
If you use one of the bands in 5W output power mode, the radio gets so super hot in a few minutes, that you can’t touch the metal parts on it. I didn’t try to run it longer because I was afraid that it’ll catch on fire :)
A few months ago I was asked by Packt Publishing to help reviewing a book called Building a Home Security System with BeagleBone which you can buy and read here.
Now they asked me to write a review of their recently released book titled Raspberry Pi Projects for Kids. I’ve read it on the weekend, and liked it very much. The author knows how to keep the attention of the reader (who is possibly a kid) through the book.
The introduction section is pretty straightforward and well illustrated with photos, so anyone can understand how to power a Raspberry Pi up and install the operating system. The book’s structure is good, it’s nice that the introduction starts with using Scratch which I think is a very good tool to show kids how programming works. Building a simple Angry Birds clone with it is quite simple yet entertaining, and shows a lot of the capabilities of Scratch.
The next chapter is about building a simple controller device and wiring it to the Pi. The author should have included some actual photos of the building process, not just schematic images, but at least those are fine and a crafted kid would be able to build it by reading the book. The Python examples are easily understandable and explain GPIO pin usage clearly. The interactive map chapter shows how to use GUI elements with a nice example using Google Maps API to download map images and displaying it in a self made application window. The chapter also explains how to interact with the window.
I think Raspberry Pi Projects for Kids is a very cool book for a child who is interested in how programming works, and wants to try it out quickly and easily without being bored reading other science books about programming. If you have a child who might be interested, go buy this book (and a Pi)! :)
I started using Github in the past few months for hosting my hobby projects. Here’s the list of my current repos:
- nweather-wordpress-plugin: WordPress plugin which shows graphs from data uploaded by nweather-upload.
- nbackup: A simple backup script which uses rsync or rdiff-backup over SSH to back up directories.
- ntimelapse: Scripts for processing webcam and sound uploads, generating and uploading timelapse videos to YouTube.
- ntimelapse-upload: Captures and uploads multiple webcam images and sound recordings to a PHP script.
- nlogrotate: A simple logrotate shell script I use in embedded enviroments.
- nweather-upload: This script can be used to upload a WS-2300 (or compatible) weather station’s data acquired with fetch2300.
- nalarminterface: Alarm system USB interface firmware, host application and other tools. Also a nice example on using XMEGA USB devices and libusb for communicating with them.
- nusbreset: Resets Linux USB devices.
- pcsensor2: Reads temperature from a TEMPerV1.2 USB thermometer (VID/PID 0c45:7401)
- homerseklet: A webpage for displaying temperature graphs.
I’m planning to fix the APRS unit in my car as it’s not working well anymore.
Gerecse WX and new webcams
And here’s the unbelievably cool Trabant from Pusztamarót:
MySQL is not very cross-compile friendly, but hey, let’s give it a try.
» …continue reading ‘Cross-compiling MySQL’
Here’s how to set up RADIUS authentication using FreeRADIUS and an Active Directory server. For example, this can be used for authenticating Wifi WPA Enterprise clients (when you connect to a WPA Enterprise Wifi network, you have to give your username and password, not only a password like when connecting to a WPA Personal network).
» …continue reading ‘FreeRADIUS AD authentication’
Here’s a quick guide on setting up 802.11n Wifi on a RouterBoard for a multi-user enviroment.
You have to set the channel width to 20/40MHz HT above or below. 802.11g uses 20MHz wide channels, 802.11n uses two of these, and you have to specify where to expand the 20MHz channel (above or below). So if you are using channel 0, you have to make sure that it is set HT above, and if you are using channel 11, HT below. On channel 6 you can use both, use the freq. usage scanner tool to decide which portion of the channels are less used.
If you are using the 5GHz band, make sure DFS is turned on. WMM should be enabled, and if you want the clients to be able to see each other, turn on default forward.
Data rates tab
Basic rates should be set to the minimum, and supported rates should be set all the way up for 802.11b/g.
Distance should be set to indoors, and periodic calibration should be disabled. Set Hw. retries to 4, and preable mode to short.
All HT chains and AMPDU priorities should be enabled.
HT MCS tab
HT basic MCS should be set to MCS0, and all rates should be supported.
If you are using more than three APs near each other (all spread evenly on channels 0, 6 and 11), then you should set the TX power to the minimum (typically 10-12dBm in an office enviroment), to make sure no APs are interfering on the same channel.
Here’s a short music video about our holiday trip.