Andrey Mikhalchuk’s Blog

You’ve probably heard about Pleo - the greenest and coolest dinosaur available on today’s market. My daughter got one for her birthday recently from her loving parents. She enjoyed it for a few days and then just got bored because it was the same moo, mrrr and urf and not much walking at all. Well, two more days of interest were raised with additional downloadable personalities, but that was it.
I tweaked the dino into something more interesting and made it wireless, so you can issue commands to it remotely (via bluetooth). Ok, one more day of fun. Then I wrote something a bit more usable then Dinomite and other tools available from Ugobe website. The development was going well until one day Pleo didn’t wake up …

I don’t know exactly what causes the problem, but I’m unable to download anything from HP (Hewlett-Packard) website. I tried downloading using multiple FTP clients from different platforms and it appeared that Safari under MacOS can download the files, while Firefox under both Windows and MacOS can’t. Right now I tried to get the same file from two XP computers using FireFox and one was able to download the file, while the other one wasn’t. It’s not about firewall settings and not about passive/active mode. If someone knows the reason and how to fix the problem I’d appreciate a comment on this post.

If anyone else is experiencing the same problems use the following solution: copy the URL of the link you’re trying to download the file from (in FireFox right-click on the link and choose “Copy Link location”), paste the link into the browser’s address line, replace “ftp://” with “http://” and hit enter. This will download the file using HTTP protocol.

I’m moving to another place. Right the next day I submitted the notice to the leasing office my kids, being under great impression of “Blue’s Clues” TV program, started playing clues. Soon they invented that the best clues can be made with marker on walls. I spent about 1 hour trying different substances on the walls, but the wall-marker combination was much stronger then Soap, Magic Eraser, OxiClean, rubbing alcohol and other pretty powerful substances. Only in a few weeks I recalled what I was studying on chemistry at school and solved the problem in seconds.

Many people are dreaming about consolidating all media files (video, music, pictures etc) in a single place. For some it is a huge full of DVDs, CDs and photos. Others buy hardware media servers and store all files in them. I chose a solution based on Archos 605 WiFi and a Linux Server running UPnP Media Server. Here’s how it works …

You ran ./configure and got “configure: error: C++ compiler cannot create executables”. Here is how to fix it …

I was recently installing squid at home as a single caching proxy for all computers in my home network. The simple way is just running squid on your linux router as is and configuring every single browser on all computers in your network so they access internet using squid. That’s doable, but boring. The more interesting way is setting up transparent proxy so all your http traffic goes through squid automatically. I’m not going to explain how to setup the transparent proxy as there are tons of articles in the internet about that, for instance:

• http://www.cyberciti.biz/tips/linux-setup-transparent-proxy-squid-howto.html
• http://tldp.org/HOWTO/TransparentProxy.html
• http://www.deckle.co.za/squid-users-guide/Transparent_Caching/Proxy

The documentation is very straightforward, and has just one problem: it is outdated and doesn’t work with the most recent versions of squid. I’ve read several instructions and was always ending up with these error messages:

Here’s how to fix the problem …

A year+ ago I’ve got my Motorola RAZR V3T (free with 2-year subscription from T-Mobile). Almost immediately I ordered 1Gb card that would fit more information and music. Of course I chose the cheapest one. At the moment the best offer was 1Gb Kingston card. Unfortunately when I inserted the card into the cellphone it did not get recognized by the phone. It appeared that only “compatible” MiniSD cards could be used with the cellphone, but that “compatibility” cost twice more. So here is how to make your “incompatible” card work with that cellphone.

So you did something and your windows explorer is now displaying thumbnails without labels?

Here is how to cure it: switch to any other view mode and then switch back to thumbnail view while holding shift key. Nice! How many tiny features like this one windows hides inside?

Unfortunately most servos you can get for a reasonable price are not the same. Each servo has its own parameters and the cheapest ones for not allow adjustments. Fortunately in the “routerbot OS” your can easily fix that problem. Here is how you can do that in the “routerbot” project.

The routerbot we almost have built as descibed in the routerbot project is self-sufficient, but you can get more fun with it if you put an inexpensive wireless camera on top of it. This post describes how you can do that.

Ufff… the most critical part of your robot project is done. Now it is time to do basic tests and assemble whatever you have done. Here’s is hwo you do that…

Linksys WRT54GL original operating system was not designed to control external devices, so we need to rewrite it with something more suitable. This post explaines how to do this and provides the new firmware. You may also want to refer to the overall project outline.

WRT54GL router is not capable of controlling mechanical parts as is. So we need to add a communication port to it. This post describes how to do that. The complete outline of the routerbot project can be found in this post.

Linksys WRT54G router and similar are very famous because of great modifications potential hidden in the device. For some purposes you may want to add a serial port to the router. You may need that for development purposes or to turn the router into a robot for instance. This post describes the procedure of taking the router apart so you can get access to the serial port connector hidden inside.

For our robot we will need the following parts and tools:

Somehow my kids became huge fans of different kinds of robots, starting from teleoperated planet explorers and ending with transformers. So I promised them to build a robot, and in a few days I ended up with this result which I’m pretty proud to share. It appeared that for $150 or less you can build pretty cool robot that is way easier to program then most robots out there on the market + its range is way larger then most toys have. Here’s how you can build your own inexpensive yet powerful robot…

Imagine you need to create say 10 disks with predefined partitions loaded with some software. The ideal solution would be automatic disk partitioning and copying the software to it. While copying files is an easy-to-do everyday procedure partitioning is a bit more tricky (really, just a little bit). Here is a quick trick that will allow you to partition disks quickly.

Windows explorer in XP has very nice feature of displaying folder contents as a filmstrip. It is very handy to browse lots of images. Unfortunately the logic of turning it on and off this feature doesn’t perfectly match the reality. Here’s explanation how you can enable filmstrip view for your folder

Imagine you’re repartitioning a disk and when you quit fdisk writing the new partition table automount tries to mount new partitions. So instead of refreshed disk ready for newfs you get this warning:


WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the next boot.


So you can forget about newfs for awhile. What do you do? Just reboot? What if you need to repartition more then one disk? Here is the solution …

Uff that was tough one … If you decided to make your mail communications more secure you probably switched on SSL option in your mail client for POP3/IMAP/SMTP servers. There is a good chance you will get one of those errors that sound like

The server you are connected to is using a security certificare that could not be verified.
A certificate chain processed, but terminated in a root certificate which is not trusted by the trust provider.
Do you want to continue using this server?

I spent way too much time solving the problem because what was just annoying message in Outlook appeared to be serious problem in MacMail. It was not capable of working correctly with that problem. In addition to that I tried to solve the problem using Plesk 8.2 that was a mistake. It appeared that whatever you do with certificates in Plesk that doesn’t affect the mail. So here is the solution for the problem: