Monday, August 27, 2012

IR sensor panel for line following robot

If you are a beginner for robotics this blog will help you to get some knowledge about robotics.Major part of a line following robot is sensor panel.You can make line following sensor panel using IR,LDR,photo transistors etc.


I will show you how to make a good sensor panel using IR sensors.

Specifications
  • Operating voltage: 4-5.0 V
  • Output format: digital I/O compatible
  • Optimal sensing distance: 4 mm
  • Maximum  sensing distance: 20 mm


Sunday, August 26, 2012

Motor controller driver circuit using L298







I made a DC motor controller circuit using L298 to control a single motor.You may already know that L298 can be use to control two motors.Yes you are right,but maximum out put current of the IC is 2A when we use it to control two motors.But if your motor's stall current is more than 2A,it is good to having a motor controller which can produce more than2A current to get the maximum use of motors.Specially when you are designing robots you need high torque motors.So you need high current motor controllers.

Take a look at l298 data sheet page 7 figure 7.You will see a solution for drive a motor which having stall current more than 2A. But you must take care to parallel channel 1 with channel 4 and channel 2 with channel 3.


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My design is quite simple.It is easy to understand by looking at the schematic.I made the PCB using proteus software.



Here D1,D,2,D3 and D4 are shottky or fast recovery diodes used to protect transistors from surges.Use a set of 1N5819 (or alternative 1N5818) schottky barrier diodes.You can drive up to 30v DC motors.The maximum current is3.5A.It is wise to mount the diode bridge o the motor when l298 and motor is not close each other(if space between them about 1m).

In my own experience I'd like to say you that don't ignore to insert 100nf non inductive capacitor.Though you didn't insert capacitors to you design it seems to be work properly,but microcontroller is going to be reset every 3 or 4 seconds.Before e I posted my design without having capacitors.Corrected design is now uploaded.
I'm still learning on l298 motor driver and I will update my blog up to my knowledge.