I've finally made it! Now I can read distance to the closest object with help of ultrasonic range finder Devantech SRF10. It took two days to make it work and communicate (actually it is due to my own stupidity...) and a lot of help from my father! Thanks, dad!

On this video you can see how things look like now. You can see that I reworked LEDs so they look much more solid :) and representable. Also I put all DB-9 contacts into cases, so it is much easier to unplug them, and quite a lot safer to use them because you don't need to worry about accidental short circuit.

I tried to demonstrate the work of sonar. You can see that LEDs can work in to modes, which I can switch with that tiny black button (so called "soft button") on Command module. In the first of them LED-console shows a demonstrably a distance to the object: the furthest the object - the more LEDs are on. Seems very natural to me and what about you? As you can somehow see I move my hand closer of farther to/from range finder and LEDs dynamically (they refresh about three times per second right now, but no problem to make them refresh 15 times and even more often) change their "level of signal".
The second mode represents the measured distance in binary format on LED-console with the least significant bit represented by the closest to us LED. The value of distance is in centimeters. This mode is handy to check a robustness and accuracy of sonar. As you can see it is actually not to consistent, it returns for almost the same situation quite different values. But I think the situation can be improved by playing with internal settings of range finder. I didn't get into that yet, though, but it will be my next logical step and I'll report of the results. Ok, thats all for today, enjoy this video and don't forget that it is very pleasant to get some feedback from you, people!

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