Hi,
I’m using a QTR-HD-01A on a very simple way. I’m just connecting it to a 5V power supply and reading the output on a oscilloscope as it is shown on the following drawing:
In front of a white surface I get 263mV, it seems correct.
But with nothing in front of the sensor I get 1.59V when I was expecting 5V.
The set up is:
What am I doing wrong? Why don’t I get 5V?
Many thanks.
Hello.
It is possible there is just a lot of ambient IR light in your space that prevents the output signal from going higher, but it would be very unusual for the effect from that to be as dramatic as what you are seeing. Can you post some more pictures of your setup including ones that show the board at different angles and how your probes are connected? What power supply are you using, and how does turning off the room’s lights affect the results?
- Patrick
Thanks Patrick for your message.
This is the setup, an adjustable power supply adjusted at 5V and the sensor pointing to the ceiling. Giving 2.121V now.
On this one I printed a box for isolating external light and pointing the sensor to a black cardboard. 1.767V.
Here you have the detail of the sensor inside the printed part and pointing the black cardboard.
If you nedd any more information, I’ll be pleased to provide.
Thanks.
Can you post some close up pictures of both sides of your board? Please try measuring your power supply voltage and the output signal directly at the boards pins.
Also, do you have any other QTR sensors you can try to see if the behavior is similar?
- Patrick
Good point!!!
Taking a nice close picture made me realise that ground soldering was not properly made.
Soldering re-done and it works as expected.
Many thanks!!
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