www.qianqin.de

Green IT is a big topic, that’s why more and more computer power supplies get a 80 PLUS label for showing off their superior efficiency. But if you every decide to run a Intel Atom based PC, use a PicoPSU, just power your notebook or charge your phone, you won’t really find out how efficient the power supply is. I came across this problem while searching for an efficient power supply for my new Atom-based home server. First, I wanted to use an 80 PLUS 350W power supply, but after reading some reviews, I found out that they are totally inefficient (<50%) on low load (<50W), which the targeted power consumption of my new home server is supposed to be. So I googled and found the PicoPSU, advertising >93% efficiency. Wow great, but wait, it needs to be powered by 12V DC. How efficient is the converter from 110/220V AC to 12V DC? No word on the manufacture site. I tried to google for efficient converter, so I gave up… until the case of my new home server arrived, a Gigabyte MIB T5140. Read more »

During my last semester, I participated at a seminar. My topic was “Games on the cell phone”. I’m putting the text I wrote online. It’s in German, but if someone is interested, feel free to have a look.

Spiele auf dem Handy (PDF)

Li-Ion batteries are practically everywhere. They are used for mobile phones, notebooks, even cars. But most people don’t really know about them and give out wrong hints on how to use and charge them. So here are two important facts about Li-Ion batteries you should know:
Read more »

Being a student at the TU-Berlin is quite nice. Our campus is right in the city, so it’s quite easy to go shopping right after your classes. We have a canteen called “Mensa” for the students too, serving really cheap food. You usually pay around € 1.90 for some meat, plus € 0.30 for some potatoes or rice and another € 0.30 for a little salad. € 2.50 for a meal, sounds good right? Unluckily, there is a catch. The food tastes incredibly bad. Most students know that, but the alternative is the workers canteen, which offers quite nice food, but for € 4.00 a meal. So what about students like me who don’t have the money to eat the expensive food every day but don’t want to puke after each € 2.50 meal from the Mensa?

Read more »

I’ve learned about an interessting illusion called McGurk effect. It shows how your brain is not only using your ears to hear things, but also your eyes. Sounds crazy, but it’s really like this. A specific example of the McGurk effect is hearing “da da da” with eyes opened and watching the video, but hearing “ba ba ba” once you close your eyes.

Read more »

Temporal masking describes the effect of your ears missing quiet sounds after hearing a loud sound. This effect is probably known by most of you (temporal post-masking), but did you know that this also happens before you hear a loud sound (temporal pre-masking)? How can your brain know when hearing a quiet sound that there will be a loud one coming and dismiss it beforehand? Magic? Can our brains peek into the future?

Read more »

To survive the ongoing price war in Germany, almost all big companies have reduced their service level to a minimum. What used to be free has become quite pricey. Service numbers are a good example. They used to be free or on a 0180-2 basis (€ 0.06/call). But lately, they were swapped against expensive 0180-5 (€0.14/min) or even 0900 (usually above €1.00/minute) numbers. It wouldn’t be so bad if the service would actually improve as expected if you pay money to talk to the service personnel, but in reality, they get even worse. Long waiting lines and user unfriendly interfaces make you pay for wasting your time. Luckily, there usually is a way to get rid of the pricey part.

Read more »

Is it possible to upgrade a notebook? Until a few days ago, I’d say only hard disk and memory. But guess what, there is more! I’m not talking about PCMCIA cards here, no, real upgerades just like in your desktop pc.

Read more »

Good sound systems have a subwoofer, that’s why I needed one for my little car. Because my car’s trunk is extremely small, I needed a special subwoofer case to fit it in without robbing space or removing the spare wheel. So I constructed one myself. Read more for some more pictures.

Read more »

Scratches are the one thing you definitely don’t want to have when you get a new PDA. A screen protector is a must have. There a 2 kinds of screen protectors in general. One kind are the cheap ones, €1 for 10 protectors. The other kind, the kind that actually protect your screen, costs €10 for 1.

Read more »