HiLetgo 5pcs HC-SR04 Ultrasonic Module Distance Sensor

The media could not be loaded. Arrived at the door the day after ordering! No messing about or delays.These sensors are excellent value for money, 5pcs for $9, bubble wrapped for safe shipping.A project was built in around 10 minutes to make use of one, as seen in the attached video. There are plenty of libraries for Arduino use and they work as described. Detection range has been measured up to 10ft for tiny movements.These are sure to end up in robot line follower projects, maybe a mosquito repeller circuit (I so hope so!) and a screen based range finder. They would also suit home security projects.

This is a pretty standard part, but there are places where companies could cut corners. HiLetgo did not do that here. These are quality parts that are reliable and simply work as expected.The five-pack is great for when you want to build something that can measure its clearance on all sides or when you want to build more than one project that needs the ultrasonic distance sensor.These sensors are part of a class that I'm teaching, and I know I will not have to worry about hardware issues for my students when they use these parts.

I hooked these up with an ESP8266 IoT device in order to measure whether a garage door was open or closed. Works good.

In my tests, clutter was a much more difficult problem than I was anticipating.I expected that enough of the mass of the signal would be going straight out and coming straight back that it would dominate and overwhelm any sideways components, making this effectively "range to the thing you are pointing at." Unfortunately that is not the case. This will pick up objects from just about 90 to 120 degrees off center line, which is HUGE in comparison to my expectation.Put in other words, If you were to set this on the long side of a table, pointing across the whole surface toward a door, you would not be able to tell that the door was open or close, as the signal reflecting off the table surface would "short out" the echo. You would only get a signal that was a closer match to the sensors height off the table.I'm still investigating possible options to shape/lens the sound for a more directional measure...

Good and fast.

Does not hit max distance it claims.. Only effective to about 70 inches.

WARNING: These sensors are defective - they stop responding after a few seconds or minutes of use.I have an HC-SR04 from a different kit (the Elegoo EL-KIT-3 Arduino Uno starter kit) that works great. I started a new project a few days ago that needed a range finder, so I ordered a few of these and used one of them in my project.To my surprise, the range finder became unresponsive after a brief period of use. Power-cycling the range finder caused it to become responsive again, only to fall asleep again after a brief while.I checked my wiring and Python code - no problems.I searched the web for people who have similar problems, and found a large number reporting the same problem. (Search for "hc-sr04 stops responding echo" to see what I found.)The issue is that *some* HC-SR04 boards have a fatal bug. To confirm my suspicions, I swapped the cable from this HC-SR04 to the Elegoo HC-SR04 - it ran flawlessly for an hour without any changes.Apparently, the HC-SR04 responds to an input pulse (on the pin labeled TRIG) by providing output pulse (on the pin labeled ECHO), but also expects to receive an echo on the ECHO pin. Sometimes, a microcontroller may not promptly return an echo, or the HC-SR04 will simply miss it. Many HC-SR04s are programmed with a timeout; if they do not receive the echo within a brief period, they will resume operation. However, some HC-SR04s do not, and they will wait forever for an echo if it is initially missed. Some people have worked around this bug by pulsing the Echo pin to knock it back into operation, but with some HC-SR04s - including the ones for sale here - it's not possible. The only way to resume operation is to power-cycle it.tealdeer - Don't buy these. Buy HC-SR04s from another vendor.

muy buen producto