Fortsätt till huvudinnehåll

Improvement of Skype


Being abroad I'm using Skype regularly. During calls with some people, the call starts just fine but is drenched in low frequent noise after a while.

From some instrumental recordings I've done using my laptops internal mic, I knew that it has quiet a lot of background noise. What if that noise is transferred to the other persons speaker, amplified, fed back into my speaker, fed back into my mic again and added to the background noise it produces already, back to the other persons speaker and back again creating an unstable positive feed-back loop?



The theory was easily proved in practice. By using head phones, the feedback loop was broken and the high levels of noise disappeared.

The software engineers at Skype could probably have good use of the noble teachings of Nyquist to get rid of this. I bet though that a simple noise gate could do the trick. There is one such avaliable online as a plugin but Skype hasn't incorporated that in to their software yet as standard.

Kommentarer

Populära inlägg i den här bloggen

The heating system

One of my former projects was the design and practical realization of an automated wood fired heating system. Two key characteristics of the project were the reuse of junkyard bargains and realization of electronic system starting from component level. Budget was kept low. The system is now warming a house situated on a farm on the Swedish countryside.  I for sure have never done a project spanning so many different categories of work. In the end I had done manual metal work and welding, plumbing, electrical installation, creation of control- and calculation algorithms, circuit design and programming to name some. A box on the upper floor of the house with an Atmega328 microprocessor controls the whole heating  system.   Here is a video summary of the project: Systems furnace is a Braland 21 from http://www.braland.se The control system that is now up and running can among other things monitor 16 different temperatures, control all the systems...

[VAWT] Affordable wind measurements

The shop Clas Ohlsson in Sweden sells a spare anemometer for the   WH-1080 weather station  for a hobbyist friendly price around 15 euros. This anemometer can probably be found in other countries too. The WH-1080 spare anemometer Here   you can read about how to use this anemometer together with an Arduino or any other embedded system.  As we couldn't find any data on the characteristics of this sensor, we did our own calibration in a wind tunnel and the results are presented in the report above. This anemometer was used in a Bachelors Thesis project related to the devlopment of optimization of the Savonius Turbine, here tagged [VAWT].

Line follower robot prototype

Before Stockholm Robot Championship 2013 I built a prototype for a line follower robot. The goal was to build something quickly that would be easy to modify, get it to go around the track and then learn as much as possible for a perhaps next version to come. It's the first robot I've built, apart from basic one we built in a project course.  I tried an Olimexino ARM development board for this project. It's basically an Arduino clone but it's physically smaller and lighter than the Arduino Due board, and cheaper, at least on eBay. I had slight problems with the drivers on this board. Here are some info about Olimexino drivers that at least helped me: http://forums.leaflabs.com/topic.php?id=73  However, when considering the "bang for the buck" Olimexino is still an attractive choice when compared to Arduino I think.   I have some stuff laying around in the drawer that I would like to try out on this robot if I choose to continue on it. For instance I w...