Notifications
Clear all
Topic starter
2019-11-03 6:57 pm
Dear Bill,
I followed the video RCWL-0516 Microwave Proximity Sensor - With & Without Arduino. An excellent tutorial which helped me a lot.
It works fine. I added a LDR to CDS and attached a relay in order to lit a lamp when it is dark and there is movement. I didn't use a microcontroller.
My question is the following:
is it possible to lit the lamp when it is not so dark, I mean can you change the sensitivity with another LDR (the resistance of an LDR)?
Or could you use a digital light sensor instead, without the use of an Arduino or other microcontroller?
Attach D0 from the light sensor to the OUT of the RCWL module.
This sensor module has a sensitivity potentiometer.
Thank you for your response
2019-11-04 2:46 am
Dear Bill
This only sometimes works.
Another way to get his attention is to try this...
"Oh Great and Powerful Bill. Creator of the many, and teacher of the huddled and uninformed masses. I implore your unmatched intellect with a problem that has been plaguing my family for generations, which only a man of your totally superior talent and design skills could possibly solve. I bow to your wisdom and beg an audience for assistance with a solution"
On the other hand, that almost never works, so you should just try saying...
Which is much more efficient, and far less grovel-ly
(whenever you use a persons "handle" preceded by the "@" symbol on this forum, it directly notifies the person mentioned that he (or she) has been mentioned)
2019-11-06 7:40 am
I'm not Bill, and with that pot of his lately, who would want to be eh? 😀
BTW, I am no expert in electronics, but if you google the following:
- Darlington Pair (2 transistor arrangement, increases gain and offers faster switching)
- Schmitt Trigger (incorporates hysteresis, turning an analog signal into a defined digital one)
... it just might lead you to what you're looking for.
Good luck!
2019-11-06 9:00 am
If you want to keep it simple, you could change the sensitivity by using two LDRs in parallel, effectively halving the resistance or add another standard resistor in series to increase the resistance.
What you should bear in mind is, that by adding an LDR to this board, you are creating a voltage divider. I suggest you read up on those!
Topic starter
2019-11-06 9:12 am
Thank you both for your replies.
I will read about the tDarlington Pair and Schmitt trigger and will try the suggestions of Pugwash.
The answers are my light in dark;)
Yvonne
2019-11-06 9:36 am
2019-11-06 2:34 pm
If you haven't got one already, one or two of these are pretty useful to have in your workshop:
Search term: Seven Decade Programmable Resistor Board
I use them for calibrating voltage dividers and fine-tuning the output frequency of 555 timers, among other things. They cost less than €3.00/US$3.33 and they are a lot more convenient than rummaging about, looking for specific values of resistors in little packets just to do some prototyping.
Topic starter
2019-11-07 8:31 am
Hi Pugwash,
Thank you very much for your replies. I ordered the board and downloaded the pdf.
Have a nice day.
Yvonne