This week, my work is mainly on sourcing the different types of LCD display and compare the different type to finalize the selection.
The selected LCD should fulfill the following requirement:
1. Small enough to fit into the robot.
2. Can display either character or graphics (LOGO).
3. Should be low power consumption.
Based on the three criterions above, I searched all LCD modules from Farnell and Rssingapore which are electrical component distributors and confied my search within 5 display modules. Two are Alphanumeric LCD modules; two are OLED graphic module and one are common LCD graphic module.
Compared with these 5 modules. The Alphanimeric LCD module is normally easy to implement but the size is larger than the graphic module and they cannot be controlled in pixel level. That means the alphanimeric cannot display graphics. For the graphic LCD module,  the size is much smaller than the alphanumeric  and power consumption is low, espically for OLED modules. Also there are no problem for display  both characters and graphics because graphic LCD module has more freedom compared with alphanimeric LCD module. Ideally, the OLED module is the one should be used.
 However, there are a lot of technical problems need to solve if we are trying to us graphics module. 
The three major problems facing as below:
1. Signal voltage level is low compared with common 5V signal level. This will result in interfacing different device under different signal levels.
2. The programming workload will be heaviers. It is because we need to program every character, draw the graphics and animations. It will consume a lot of
     time on it.
3. Some datasheets of the graphics LCDs do not provide enough information for the development. It actually limits our choices.
In the disscussion with Charith, we try to find a kind of LCD which has the character data base already but can also be used for graphic. It would be the most ideal situation. It is under discussion with Charith.