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[DPRG] can i use a bulb mounted on an object for identification?

Subject: [DPRG] can i use a bulb mounted on an object for identification?
From: LO VENG CHEONG d961706 at wkg1.umac.mo
Date: Thu May 18 06:43:43 CDT 2000

Hello, friends,
  I have made the basic platform of my robot. Before, I met some problem
in driving the motors with the Handyboard. Since the Handyboard use the
L293D H-bridge chip to generate the PWM signals to the dc motor but the
peak current gives out is just 1.2A, since the common toy motors sometimes
draws up to about 3A. This causes the handyboard to reset and stop the
motors. I have just solved this problem by isolated the motors with
another separate power supply. So, the motors work ok now.

  Another problem met is that two motors rotate on different speed even
giving the same PWM signal. So, it can't go straight. Then, I tried to
tune the motors by adjusting the power level using the PWM technique. And,
it can roughly go straight now. I know that it is not a good method. I
should use the shaft encoder. And i think that i may try to hack the shaft
encoders from a mouse. As some of you taught me that I can hack the wheels
and the light emitter and receivers but I don't know how I can interface
theses to the i/o ports of my controller board and what is the operation
of the receivers?

  Now, I am trying to do the object identification. As there are no
constrain made in my project, any method can be used. My partner has a
idea that we can mounted a bulb directly on the target object (say a can),
so that it would give a light source to my robot. And, we try to use the
two photoresistors to detect the lightest place in the room. So that we
can find out the can and grab it by the gripper. Is this idea ok? and can
the robot would stop accurately each time at a certain distance?

  Any ideas are wellcome!

Thank you very much!

Raymond Law in Asia    

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