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Hi. I am building a robot that will be guided to 3 different locations using infrared. What I'm planning to do is to have IR transmitter in each location to transmit modulated signal to the robot.
My problem is how to design a circuit that can transmit different serial code through IR, and the robot can differentiate the signal from different IR source.
So far, what is in my mind is to use parallel to serial register IC to change into serial data, and modulate it using 555 timer. But I very unsure whether this is the correct way.
If this is possible, what are the common IC available and how should the circuit look like?
For receiving part, I will be using PIC16F877A microcontroller with IR receiver.
Another problem is how to make the robot stop like 1 meter before it reach the IR transmitter.
I have changed my mind.
Now, one IR beam of the 3 transmitters) is to modulate the TX carriers with 3 different frequencies. This will be equivalent to sending 3 different patterns (continuously) as in the following example:00001111… equivalent to frequency= F00110011… equivalent to frequency= 2*F01010101… equivalent to frequency= 4*FBut for receiver side, I need to use serial pin to decode it? If yes, what is the logic behind it?
You're just making it much harder on yourself this way.Using one carrier frequency, you can receive all signals with the same integrated IR receiver.You won't be able to get the integrated IR receivers in F, 2F and 4F, so you'll need to design and build sensitive IR preamplifiers - not a task for the uninitiated.Sending F, 2F and 4F concurrently from one tower will give you a headache, as they mix into sum and difference frequencies - you'd be much better off using just one carrier as I described.
Correct me if I am wrong,
but you might have misunderstood it. What I mean is to have the modulating frequency changed, not the carrier frequency. This way, I can still using one integrated IR receiver.
Please comment if you think this is not the way.
but need to know what is the circuit to program it?
Quotebut need to know what is the circuit to program it? Did you read my post above?The info you need is out there on the web.