433Mhz not working well far range

Thread Starter

Jambu

Joined Sep 15, 2021
19
Hi all,

I have been trying to build a wireless PIR sensor successfully to no avail.
Pretty new to electronics here so please pardon any wrong terms/details being left out.
So below is a circuit I built, when there is a motion being sensed, it will trigger the light to lit up for few seconds through the 555 timer.

1.JPG

2.JPG

It actually works perfectly if I did it NOT wirelessly, or when they are both very near beside wirelessly.
But my main problem is, when I start testing them far apart (less than 3 meters which I read that without antenna the range could go up to 3metres, but right now even below 3metres, it couldn't sense properly and moreever I did solder antenna to each of the modules)
It could either transmit the signal over, but the light just continued lighting up until I bring them close enough to sense it to turn off.
Or it just couldn't even send any signal over.

I am currently using a 9v battery to supply both, as I understand that the receiver module have to receive 5v, my 9v battery goes into a 5v regulator which supplies the voltage to the decoder and the receiver module.
And as for the transmitter module, I supply them directly with a 9v battery.

Here is how I connect them in real life.
IMG20220810230956.jpg



I feel it may have something to do with my type of batteries/wrong voltage supply, but I just couldn't figure what is it.
Appreciate any help!
 

KeithWalker

Joined Jul 10, 2017
2,456
You may be getting radio interference that is affecting your reception. I tried using the same type of 433MHz transmitter and receiver for a small vehicle radio control using pulse width modulation but there was too much interference from other signals to make it usable.
To increase the sensitivity, try using single wire straight antennas, both in the same physical alignment. Transmitter - 15cm, Receiver - 23cm.
 
Last edited:

MrChips

Joined Oct 2, 2009
26,792
I have not examined the modules you are using.

The RF transmission has to be modulated and the receiver decoder has to match the transmitted signal.
 

Thread Starter

Jambu

Joined Sep 15, 2021
19
You may be getting radio interference that is affecting your reception. I tried using the same type of 433MHz transmitter and receiver for a small vehicle radio control using pulse width modulation but there was too much interference from other signals to make it usable.
To increase the sensitivity, try using single wire straight antennas, both in the same physical alignment. Transmitter - 15cm, Receiver - 23cm.
Thanks! I will try this method
 
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