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Powerful • Nov 25, 2007

URGENT robot questions, deadline 1 week


Please I need help. pleanty help.....please

I am working on a line foolowing robot , that is steered by a servo and controlled by a PIC16F84 microcontroller. its is a 16cm by 16cm by 16 cm.
For the sensors , I am using 3 infrared sensors.

Do I need a comparator to compare the signals coming from the sensors considering am using a servo?

Also, what does a relay coil do?

Does the motor need to be connected to the PIC16F84? because , I thought it only needed to be powered?

How far apart shud I keep the sensors to prevent interference?

I would be grateful for any amount of information you can give.

Please try to elaborate on any explanation to help me understand.

Thank you.
harshharsh26 • Nov 30, 2007
You will need a coparator for sure, It can be a analog comparator in the form of any opamp or a a/d convertor in the microcontroller itself.
If possible show me the bolck diagram of the project u are trying it would help me to explain you more...
Or if u dont have any do reply i will try to design some for u,
I suggest the sensors should not be closer than the width of the line you are trying to follow, and also isolate the sensors so that it can only see it's respective infrared emitter reflection (you can use some sorta tube, maybe).

The relay coil is just a switch that utilizes an electromagnet. If current goes through it, the magnet pulls a switch. Quite useful if you have to deal with high voltage circuits.
caen_clux • Dec 4, 2007
dont wasting your time..for more information about line following robot you can visit at
Powerful • Dec 8, 2007
hi, I just saw your message thanx....I dont exactly have a block diagram for the project yet. But if am planning on working it out digitally , for example say,, if the reading from the sensors are 0,1,1 turn right do I still need a comparator. I would be really grateful if you can help me come up with a design...Thank u
mahul • Dec 8, 2007
u wd need a comparator to feed the analog signals from the sensor to the microcontroller in digital form.the best thing that u can do is to define two voltage levels such that the voltage from the sensor varies as less than the base level when it detects the absence of a line and more than the base level when the sensor is on the line(ie detects the line)(or vice-versa). now connect one base line and one line from a sensor to the inputs of a comaparator(there r many, u cd try the mc1458 for an example).these would digitise ur signal into two levels 0 and 1(there is furthur sophistication possible if u decide to allocate more than a bit for a line but it doesn't seem u wd require that).and connect the output of the comparator to the controller,that's direct the outputs of ur controller to the actuators as per ur requirements and ur line follower is ready.
Elektrogeek • Dec 11, 2007
You Surely would need to connect motor to PIC as you also need to stop the motor. as far as for comparator You need to have a comparator for sure to compare the voltage values.

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