Sun tracker - part I

A couple of weeks ago I got some new (used) batteries for my solar station, as you can see on the picture on the right. If they were new, I'd have something like 36 Ah, but they where on heavy duty, so I'll be happy with a humble 20 Ah. Nevertheless it came to me that if my solar panel was equipped with a solar tracker I'd increase the power production in something like 20/40% , having a more profitable battery bank. FYI the most important tracker is the E-W axis, the N-S can be almost neglected and it'll be suffice having an arm setting position for Summer, Autumn/Spring and Winter times.
For the tracker motor control I bought a couple of H-bridges, in this case the L293D, described in the bottom picture:

The chip deals with 600mA max current, tolerates peaks of 1.2A. It uses 5V for regular working, except for pin 8 which should feed the needed motor voltage (in this case I'll use 12V), needless to say that the GND pin from the 12V power-source should be connected to the GND pin of the 5V power-source.  I must say that the electronics part is quite easy to achieve, the difficult part is to manage to create a cheap and robust mechanical system, I disassembled an old HP deskjet printer and used the tray motor, it uses 19V nominal, 24V max, quite good to use in this project with 12V, it drains only 150mA of current (I measured 200mA, 400/450mA if holding the wheel). I'm now assembling it and will have pictures soon! The electronics and programming will be showed up also at that time.
The L293D truth table: