PR16 Project

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PR16 Project

Postby E11022 » Tue Nov 15, 2011 10:55 pm

Hi,

i bought both 433Mhz and 315Mhz RF module recently. I am testing the RF module by following the PR16 Project. However, the Receiver Circuit is not working. The 7-segment is in low power. I followed exactly the same as the schematic. Is there anything left out in the schematic?
DSC00167 (Small).JPG
Receiver circuit


2) Can i double confirm about Tx and RX for 433Mhz and 315Mhz? Please see the attachment. I hope i paired them up correctly.
DSC00176 (Small).JPG
RF module 315Mhz

DSC00173 (Small).JPG
RF module 433Mhz


3) Is there any other ways or faster way to test the RF module whether they are defect or not. i accidentally drop 1 RF module on the floor, i scared it is spoiled because i need to use it for my project currently .'

Thanks :)
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Re: PR16 Project

Postby ABSF » Wed Nov 16, 2011 1:06 pm

E11022 WROTE:i bought both 433Mhz and 315Mhz RF module recently. I am testing the RF module by following the PR16 Project. However, the Receiver Circuit is not working. The 7-segment is in low power. I followed exactly the same as the schematic. Is there anything left out in the schematic?


1. Are you sure you programmed the '877 (40p) correctly as the original circuit used '876 (28p)?
2. How far did you place the RX from the TX?
3. How do you know that the TX is working?
4. What did you use for the power source? 9V battery or adaptor?
5. Did you disturbed the coils on the RX and TX by accident?

To test the TX and RX, I think one can construct an oscillator using a LM555 and feed the output to the TX. On the RX you should be able to check the pulses at the output of the RX using a logic probe. Has anyone tried this out? Correct me if this doesn't make sense.

Allen
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Re: PR16 Project

Postby E11022 » Wed Nov 16, 2011 6:38 pm

1. Are you sure you programmed the '877 (40p) correctly as the original circuit used '876 (28p)?
Yes, i changed the input Port and double confirm on the programming.

2. How far did you place the RX from the TX?
Very near, only 5cm.

3. How do you know that the TX is working?
i placed an LED at the TX data line, the LED is lighten up.

4. What did you use for the power source? 9V battery or adaptor?
I used 9V battery.

5. Did you disturbed the coils on the RX and TX by accident?
I dropped it on the floor by accident. Is this gonna affect the RX/TX?


I shall try on ur suggested way to test RX/TX.

Thanks :)

Lee See
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Re: PR16 Project

Postby Brian Griffin » Wed Nov 16, 2011 7:05 pm

I thought you need both receivers and transmitters to be of the same frequency?

Also, these wireless modules are very light. I dropped it a few times back in my schooling days and it is still ok. Try not to drop them too hard next time. :)
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Re: PR16 Project

Postby ABSF » Thu Nov 17, 2011 8:36 am

E11022 WROTE:3. How do you know that the TX is working?
i placed an LED at the TX data line, the LED is lighten up.

4. What did you use for the power source? 9V battery or adaptor?
I used 9V battery.

5. Did you disturbed the coils on the RX and TX by accident?
I dropped it on the floor by accident. Is this gonna affect the RX/TX?

Lee See


A3. A lighted LED on the TX data line doesn't tell much and your LED circuit might be damping the input to the TX. It is the modulated RF that is important.

A4. Is the 5V after the 7805 adequate to operate your circuit? It should NOT fall below -5% i.e. 4.75V.

A5. The coil determines the TX and RX frequency. It was used for trimming the TX and RX in the factory for optimum performance. So if you accidentally dropped the thing, make sure the coils are not out of shape and never try to adjust the coil yourself unless you got all the necessary test gears.

Actually the easiest way to test the RF module is to get another set of them cos they are very cheap!!

Hope the best of your troubleshooting. ;) :)

Allen
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Re: PR16 Project

Postby E11022 » Sat Dec 10, 2011 11:16 am

Finally, i found a simple way to test the TX and RX module without using micro controller.It is a simple remote control circuit.

The Transmitter circuit is as below:
http://www.rentron.com/Files/ht-12e.gif

The receiver circuit is as below:
http://www.rentron.com/Files/ht-12d.gif

In my case, i removed the D1 LED to make the remote control circuit work.
The remote control circuit work perfectly, hence it is proved that my RF module is working. Just that i found out the transmission for TX 315 module is a little bit unstable as the module itself is unbalance on the breadboard.

Thanks everyone for helping and i hope that my findings on this would help others too. :)
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Re: PR16 Project

Postby E11022 » Sat Dec 10, 2011 11:16 am

sorry it is double post due to error.
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