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simple transmitter & receiver

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jayman

New Member
I am building a senior project for my EET class and need a design or schematic for a simple transmitter and receiver; (some thing like a radio colar tracking device for wild animals, it emmits a signal and a receiver pickes it up). A simple emitter/receiver would be great, it would fit into the project perfect. The range doesn't have to be that great only 10 meters or so. If anyone can help I thank them.
Jayman
 

Aeddon

New Member
pic ot pic transmission troubleshooting

hi guyz,
i having problem on the transmitting of data transfer from mcu A 16f877a and recieving in mcu B 16f877a.
i connectly tx pin from mcu directly to the transmitter and likewise for my reciever.
when just connect a wire from mcu A to mcu B, the thing work fine but when using of my transmitter and reciever unit, they are not working.
i have put led to show transmission on both side and only transmitting show working but receiving end is not.
you guyz have any idea to troubleshoot ?
i give the tx/rx unit 5vdc supply
my transmitter and reciever is attached .
 

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Rajaneesh

Member
hi guyz,
i having problem on the transmitting of data transfer from mcu A 16f877a and recieving in mcu B 16f877a.
i connectly tx pin from mcu directly to the transmitter and likewise for my reciever.
when just connect a wire from mcu A to mcu B, the thing work fine but when using of my transmitter and reciever unit, they are not working.
i have put led to show transmission on both side and only transmitting show working but receiving end is not.
you guyz have any idea to troubleshoot ?
i give the tx/rx unit 5vdc supply
my transmitter and reciever is attached .
Publish your circuit diagram here....i need to see how did you connected the ASK module and the controller... State the voltage in all the points in circuit....
 

Aeddon

New Member
Publish your circuit diagram here....i need to see how did you connected the ASK module and the controller... State the voltage in all the points in circuit....
sorry but i haven finished up the circuit diagram

i give you the explanation of it(Sorry)

i am using 16f877a for both transmitting ans recieving,

for the transmitter side

i connect directly to the data of the transmitter ans portc pin 6 of the mcu
ground of transmitter to common ground
vcc to 5vdc (roughly 4.86v)
ant of transmitter to a 30cm long antenna

for the receiving side

i connect directly to the 2 data line of the receiver unit and portc pin 7 of the mcu
the ground line all to common ground
the vcc all to 5vdc (roughly 4.86v)
ant of receiver to 30 cm long anntenna

i am using usb power by laptop 5vdc

by only using serial line, i can transmit and recieve but when come to connecting the module , its never work,

thanks for the help
 
Last edited:

Rajaneesh

Member
sorry but i haven finished up the circuit diagram

i give you the explanation of it(Sorry)

i am using 16f877a for both transmitting ans recieving,

for the transmitter side

i connect directly to the data of the transmitter ans portc pin 6 of the mcu
ground of transmitter to common ground
vcc to 5vdc (roughly 4.86v)
ant of transmitter to a 30cm long antenna

for the receiving side

i connect directly to the 2 data line of the receiver unit and portc pin 7 of the mcu
the ground line all to common ground
the vcc all to 5vdc (roughly 4.86v)
ant of receiver to 30 cm long anntenna

i am using usb power by laptop 5vdc

by only using serial line, i can transmit and recieve but when come to connecting the module , its never work,

thanks for the help

First of all , its not advisable drain power from USB for this application. Check out the power consumption of the ASK module....

Connections seem to be ok here. Check the data line of the transmitter module while data transmission...you should be able to see the data in the scope.... if that is fine, mistake is in the receiving side...

For this, i would like to know your packet frame....
 

Aeddon

New Member
First of all , its not advisable drain power from USB for this application. Check out the power consumption of the ASK module....

Connections seem to be ok here. Check the data line of the transmitter module while data transmission...you should be able to see the data in the scope.... if that is fine, mistake is in the receiving side...

For this, i would like to know your packet frame....
now i dun have the scope with me now.i will go check it tml
anyway what is the packet frame , i disable the the frame error in the configuartion bit in my prgramming
 

Rajaneesh

Member
now i dun have the scope with me now.i will go check it tml
anyway what is the packet frame , i disable the the frame error in the configuartion bit in my prgramming

Did you write your own serial communication? You have dedicated UART pins in this controller, why dont you use that for communicating with the module... ?
 

MikeMl

Well-Known Member
Most Helpful Member
Deleted. Replied to very old post!
 
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livewire_541

New Member
There's the problem....

Hi ,

From my personal experience, the main problem in wireless data transmission is the channel noise and the resulting error. The solution is quite simple:

-Find yourself a decent codec and the problems will go away.Trust me. It's "Been there, done that!"

-Try a Manchester/Dibit/1-bit differential/...etc codecs. I personally recommend the bit differential codec, it did its job pretty well.

good luck!
 
Last edited:

Aeddon

New Member
Hi ,

From my personal experience, the main problem in wireless data transmission is the channel noise and the resulting error. The solution is quite simple:

-Find yourself a decent codec and the problems will go away.Trust me. It's "Been there, done that!"

-Try a Manchester/Dibit/1-bit differential/...etc codecs. I personally recommend the bit differential codec, it did its job pretty well.

good luck!

did you have the example codec>?
mayb, but i am using asm coding
 

livewire_541

New Member
The codec...

Hi again,

I always have second thoughts about software encoding, and I don't always rely on software codecs, especially when dealing with RF applications. I recommend a hardware solution; find a circuit, build it, test it, and see the results.

Try searching google, and I'll look up in my circuit collection and send it to U when I find it.

Good luck!
 

Aeddon

New Member

hi all, thanks for the great help.
i just dun understand just by replacing single wire i got all my transmission nice and good, but when come to rf module communicating , i got nothing.
izzit really a hardware failure? i buy another unit, its still the same.
could it be my connecting is poor? ut i check all continuity and supply voltage , all is fine, the only thing i cant check is my anntenna?
my antenna is just a normal tv antenna-like rod with around 50cm long for each.
 

Rajaneesh

Member
hi all, thanks for the great help.
i just dun understand just by replacing single wire i got all my transmission nice and good, but when come to rf module communicating , i got nothing.
izzit really a hardware failure? i buy another unit, its still the same.
could it be my connecting is poor? ut i check all continuity and supply voltage , all is fine, the only thing i cant check is my anntenna?
my antenna is just a normal tv antenna-like rod with around 50cm long for each.

You have to confirm whether the UART data is coming or not.....If you have the scope its easy to monitor, other wise try to print in the hyper terminal and see what is happening... you may have to use MAX 232 in between the controller and PC....

If you are able to see the charactors which you are sending from the controller, your controller (TX side) is fine. Then your next point of attack should be on the RX side... check whether you are able to see the data in DATA out of the RF receiver terminal....
if you are able to see the data, probably RX side controller is having some trouble...either in decoding or in the data handling...

Try to do the step by step procedure and let me know....
 

Rajaneesh

Member
hi all, thanks for the great help.
i just dun understand just by replacing single wire i got all my transmission nice and good, but when come to rf module communicating , i got nothing.
izzit really a hardware failure? i buy another unit, its still the same.
could it be my connecting is poor? ut i check all continuity and supply voltage , all is fine, the only thing i cant check is my anntenna?
my antenna is just a normal tv antenna-like rod with around 50cm long for each.

Hope you have used the PIN number 17 & 18 in the controller for interfacing the RF TX and RX....
 

Rajaneesh

Member
hi all, thanks for the great help.
i just dun understand just by replacing single wire i got all my transmission nice and good, but when come to rf module communicating , i got nothing.
izzit really a hardware failure? i buy another unit, its still the same.
could it be my connecting is poor? ut i check all continuity and supply voltage , all is fine, the only thing i cant check is my anntenna?
my antenna is just a normal tv antenna-like rod with around 50cm long for each.

Instead of software codec.....I recommend to use a hardware ENCODER/DECODER ....you can find a perfect, simple and cheap chip in HOLTEK semiconductor ..... HT series...

Its simple and fast way to finish your project... Dont fiddle with the firmware for encoding /decoding unless you are expert in that....
 

Rajaneesh

Member
hi all, thanks for the great help.
i just dun understand just by replacing single wire i got all my transmission nice and good, but when come to rf module communicating , i got nothing.
izzit really a hardware failure? i buy another unit, its still the same.
could it be my connecting is poor? ut i check all continuity and supply voltage , all is fine, the only thing i cant check is my anntenna?
my antenna is just a normal tv antenna-like rod with around 50cm long for each.

For 433 MHz , you can use the UHF antenna.... or any single core straight wire....for short range..... If you need to increase the range of communication, you have to put the high gain antenna on both sides...
 

livewire_541

New Member
About USART....

Hi guys,

I just wanted to ask you about the USART in PIC16F877A.I'm Using BASIC compiler and I don't know how to use it to transmit data, 'cause I always transmit on one bit to the TX module but never did use USART.So what commands do U use?

regards.
 
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