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Author Topic: Trouble with RF module (ASK 434Mhz)  (Read 896 times)

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Offline allahjaneTopic starter

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Trouble with RF module (ASK 434Mhz)
« on: September 19, 2012, 09:18:01 AM »
Hey I got this RF transmitter and receiver pair from ebay (Says 434Mhz and ASK modulation)
http://www.ebay.in/itm/280952855034?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_1883wt_1139

Its same as
https://www.sparkfun.com/products/8950

I prepared a test circuit on a Breadboard/project board  as shown in the Attached Image

on turning on the power the Data Pin on the receiver side Always remains HIGH (+5v) no matter what

Even when the transmitter is removed from the circuit the receiver give HIGH output at data pin

I'm using the digital data pin and the ground pin to form the data out circuit as you can see in the figure labeld as data terminals

However a the data pin on receiver goes to LOW state for a split second whenever i give a +5v to the data pin of the transmitter i.e closing the D switch (this may be due to the fact that I'm using the same power Source for both transmitter & Receiver) after then it quickly becomes HIGH again

there is no tuning controls available on the pair either

What am i doing wrong? has the ASK modulation has to do something?


Please help me

Offline Billy

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Re: Trouble with RF module (ASK 434Mhz)
« Reply #1 on: September 19, 2012, 12:01:15 PM »
What is the voltage on the data input pin when nothing is connected?
Try putting a 1k ohm resistor from the data input pin to +5V and see what happens when you then ground the pin...at least I would try that.

Offline Soeren

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Re: Trouble with RF module (ASK 434Mhz)
« Reply #2 on: September 19, 2012, 01:58:09 PM »
Hi,

Hey I got this RF transmitter and receiver pair from ebay (Says 434Mhz and ASK modulation)
http://www.ebay.in/itm/280952855034?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_1883wt_1139

Its same as
https://www.sparkfun.com/products/8950

I prepared a test circuit on a Breadboard/project board  as shown in the Attached Image

First off, connect it as in the datasheet - and connect all the pins!


on turning on the power the Data Pin on the receiver side Always remains HIGH (+5v) no matter what
[...]
However a the data pin on receiver goes to LOW state for a split second whenever i give a +5v to the data pin of the transmitter i.e closing the D switch

These two statements are mutually exclusive ;)

How do you verify the output low situation?


Even when the transmitter is removed from the circuit the receiver give HIGH output at data pin

How do you verify that it's high?
'Scope , voltmeter or what?

I'd guess it received noise, but you need a scope to see that.


What am i doing wrong? has the ASK modulation has to do something?

As mentioned, you didn't connect it up fully, so please test that and post back the results.
The ASK modulation is nothing you should worry about - it's an internal thing - you'll just "see" the plain logic signals.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

 


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