I am running the RCWL-0516 from a bench power supply set at 5Vdc.
Connection to the PCB is as follows:
Vin → +5V power supply
Gnd → 0V power supply
Out → anode of and LED
The cathode of the LED is connected to ground via 390R resistor.
On power up, the LED turns on for approximately 2 seconds but from there, no amount of motion in or around the sensor will trigger the LED.
I have checked the +5V supply on an oscilloscope and it is very clean.
Sadly, my oscilloscope is only a 100MHz device so there is no chance of me testing the Colpits oscillator frequency/function.
Do you have any suggestions as to what could be the issue with these RCWL-0516 and why they are not working as they should?
Hi Barry
Doubt if any hobbyist would have an oscilloscope that would look at 3.18GHz. Actually 100MHz is a pretty good instrument. Anything over that is pretty specialised and require special probes. Actually for 90% of oscilloscope work 20 or 50 MHz is OK. Quite often with a 100MHz (usually only at a probe setting of X 10. Setting of X 1 will be limited by probe response. Usually < 10MHz) you see things which may be not there in the real world, ie; the user puts the funnies there with things like long earth leads and other measurement techniques.
The instrument to use here is s spectrum analyser. With a short piece of wire connected to the input as an antenna you can detect the presence of a radiated RF signal which is useful even if you can’t measure the actual output level.
Cheers Bob
Hi Bob,
Thanks for the quick reply.
I do not have a spectrum analyser so any form of RF sniffing is out of the question.
I have five of these modules and of the two that I have tested, no motion triggering is occurring. I have another ten modules due to arrive any day now so I really need to work out what is stopping them from working as expected.
Perhaps someone else on the forum has experience with these modules and can shed some light on what could be goin on?
Cheers
Barry
Hi Barry
You have 2 devices that are not playing fair. That is suspicious and if you get the same result with a third one I would start looking elsewhere. It would point to something you have not done (or are doing) correctly or an incorrect / poor connection. I think the connection is so simple that it would have to be correct.
This device is a doppler detector and as such the target has to be moving away or toward the detector. It will ignore sideways movement unless the movement has enough to or from component to be detected. If you are not fulfilling this requirement it is likely you will get no result.
Otherwise someone with some experience with these devices will need to chip in here. I am out of ideas.
Cheers Bob
Hi Bob,
Thanks once again for responding to my post.
I totally agree with your comment that the connection is so simple. I have replicated the configuration that most YouTubers have shown - theirs works perfectly, mine doesn’t. I will solder pin headers into the remaining three modules that I already have and see if any of them work. Failing that, I too am out of ideas…
Cheers
Barry
Hi Barry
U-Tube… I find that you need to filter a lot of it into 2 piles. Useful and Rubbish. Unfortunately you have to do this yourself and make your own judgement. I strongly suspect that sometimes there is a bit going on behind the scenes that is not shown.
Example of rubbish. A “Mechanic” (note quote marks) describing a screw he had in his hand. Funny head which looks like a hex key (Allen Key) but with points.
Here is a so called “Mechanic” who has never heard of a “Torx” head screw and driver. Used a pair of multi grips to remove it. Hope he never works on a Peugeot or similar, my car is full of those.
Soldering, how are you with that. You don’t have a problem there I don’t suppose???. Also if you are plugging into a breadboard change position in case you have a dodgy connection.
Cheers Bob
