Light-chasing Robot Head
Date: Wednesday, April 28 @ 09:17:44 EDT
Topic: Mekanik Yapılar
Our robot head project is improved a bit more. Reduced in number, this head uses only two servos. it doesn't need to be head shaped, any shape is ok, can be a sunflower, a bug or a simple arrow. anything you can imagine and manage to cut out off sheet plywood. I had had a ready head in hand, so i've used it.
This head is controlled by two separate microcontrollers. I wanted to separate light measurement procedure and servocontrol so as to enable both systems can also be used alone.
So, we got two microcontroller chips. One controls the position of two servomotors according to the info at its 4 input pins.
The other chip takes care of the light levels and measures light by its 4 separate photodiodes. By comparing all light info coming from the sensors (measured within 32 levels : 5 bit by capacitor charge discharge method), it changes the states of its 4 output pins. 2 pin for each servo. 10 to turn one direction, 01 to the other direction, 00 or 11 is stop. The same signals are valid for a H bridge circuit (can be seen at our tutorils section) as well. By using H bridges, you can use DC motors with reduction gear (or hacked servos) and obtain a more precise light following robot head.
Both chips' hex codes and the circuit schematic is at the end of the article. Read on..
The head in short, managed by two servos which are controlled by the second microcontroller, turn towards light. The first microcontroller is continuously monitoring the light sensors and comparing light levels. Commanding the second microcontroller. With the photodiodes i've used, it can easily chase a candle or a small headlight bulb in a dark place.