Hello again!
Thanks for the interest!
I’ll try to answer the questions the best I can.

@PicNick
Versions 1.0 to 1.2 did use the GP2D12 sensor but the beam of this sensor is really narrow which means that scanning an area takes a lot of time (the robot must move slowly or the scan could miss a object).
I was hoping to speedup the time needed for scanning by using the SRF08, which it did.
The SRF08 has a really wide field of view (~ 65° @ ~26,5cm) which can be adjusted to give a narrower field of view (~39° @ ~26,5cm).
The narrower field of view gives a much better scan resolution but also means that objects close to the ground are missed.
Maybe by lowering the head and or adding a 2nd SRF08 aimed at an angle will solve this problem.

@tobimc
One motor running at full speed on a flat surface will pull about 1 amp but can peak to about 3 amps depending on the conditions (surface/ turning/ climbing).
This is still within the 5 amps that the MD22 can handle.
The MD22 has also an I2C interface which I really like, I love the I2C protocol! \/

The robot is not really for outdoor use because the electronics are exposed, maybe on a nice dry and sunny day I could test it outside.

@Florian
The angle of rotation is 360° in steps of 1.8°.
A full turn of 360° without scanning takes about 1,4 sec.
I only use the sensor tower to look around but I might need to add a sensor due to a problem explained above.
I have also mounted a CMPS03 on top of the head, this to keep it as far away from any magnetic fields from the drive motors ex. as possible.
The vertical angle is fixed.
I wanted to keep the head and tower as clean and simple as possible but still be interesting.

Greetings,
H.J. Windt