Thread: Reliable Data Transfer

Hi there,

my friend is having a problem in transmitting some data.

he needs a transmitter that is able to transmit 1200bps of data, and also a receiver to receive those transmitted data. Of course, he prefers the range to be at least few hundred metres.

he bought a tranceiver kit, but has problem in:
1. getting the receiver to receive the sent data correctly
2. getting the transmitter to send data at 1200bps (even though the specification mentioned that the transmitter is able to transmit at a higher rate)

so right now, my question is:
1. the problem might be due to some impedance matching issue, where the source(generated by a 555 timer) might not have its output impedance matched with the input impedance of the transmitter
2. if he fails to solve that issue, he might be looking at other transmitter/receiver kits, which i do not have any idea where to find them.

so if anyone can kindly give me some suggestions on how impedance matching can be done or any modules that are known to be working well with the specifications that I have given.

note: he is doing this for some sort of GPS application, and now he is builing a small model of it, of which i am trying to help him when Im free.


Thanks

I've no idea what he's using a 555 for?, he should be using processors (or encoder/decoders) - and using something like Manchester coding.

sorry for the confusion

now he uses the 555 timer to simulate the data generated by some kind of source (i donno what kind of source it is), but generally the 555 timer generates a square pulses of 1200Hz, and he then connects the 1200Hz pulses to the transmitter.

he is actually breaking down his project into smaller parts. right now he is trying to get the transmitter and receiver working. hopefully a transmitter and receiver module will help him in that. then, he will focus on the programming of microcontroller, which has something to do with object tracking.

Would be helpful if you could post his schematics.

Originally Posted by chinsoon

now he uses the 555 timer to simulate the data generated by some kind of source (i donno what kind of source it is), but generally the 555 timer generates a square pulses of 1200Hz, and he then connects the 1200Hz pulses to the transmitter.

A 555 timer is about the same reliable as sending mail using pigeons. Using it to transmit data is similar to a pigeon being caught by a falcon.

The problem is TIMING!

Boncuk