Coliao 5pcs Laser Sensor Module Non-Modulator Tube Laser Receiver Module with 5pcs KY-008 650nm Laser Transmitter Module

I intended to use this to detect if the laser beam was broken when I lift my car up on my 4 post lift to keep from driving it through the ceiling of my garage. I planned to set the laser a few inches below the ceiling and if the roof of the car broke the beam, I would be alerted. However . . .I seem to have received inverted sensors. The output is high when there is NO laser detected and low when the laser shines on the sensor. Normally an inverted signal would not be a problem. However, if power is cut to the sensor, the microprocessor doesn't know the difference between seeing the laser and having no power. So using them as is, I might believe that there is no car between the laser and sensor, when really, the sensor just failed or has no power. I think this could be solved with an inverter, but now I have to buy inverters?Ultimately, it wouldn't matter because with the sensor powered up and the laser completely removed, the sensor output is not steady. Reading the sensor output with an Arduino Nano Every just shows more or less a random state. Inverting won't help that situation. Perhaps thresholds could be set in software, but should I really have to do that? I'm in a dim office, how can the sensor detect something under those circumstances? The description says that sunlight will affect the sensor, but I can tell you that, with my office completely dark, just the reflection of my computer screen on my red shirt was enough to trigger the sensor.The laser beam is bright, but it is not very coherent, meaning the dot is rather large. It's worse than the laser in the cat toy we have. In fact, the cat toy laser is a tiny little dot. I estimate this laser is roughly 50x as large at about 10' (3 m). I guess these parts are just too cheap.

First laser out if the package was bad. I am getting lots of Arduino parts from China with high failure rates. So buy lots and you should find one that works.