HC-SR04 Ultrasonic Module Distance Sensor fit for Arduino UNO MEGA Nano Robot XBee ZigBee (Pack of 5 pcs)

The first thing you notice is that these are very nicely packaged rather than the typical plastic bags. They also come with both M-F jumper wires and F-F jumper wires. The sensors work as expected and the quality of the PCB looks good. Even the solder joints look great. I would buy these again.

These are not cheap knockoffs. They come in a very high end packaging. They work brilliantly. Any library I've tried with them works great. They don't give erroneous readings like some of the cheap clones do. These are better quality than the Elegoo ones that I purchased before these. By a good bit too. Highly recommend. Will be stocking up on these.

Why did you pick this product vs others?:Got these for my daughter and they hold up just fine. Her robot is now functional with this sensor.

It does what it should, but does not work with 3.3V.

What i like is items like this are available for a good price. fun to mess with.

This ultrasonic ranging module is easy to apply, and seems quite well-made, especially considering the price.The sensors do not come with a datasheet or instructions of any kind. An internet search for "HC-SR04" should work to find the datasheet.I do think it may be frustrating to try to measure distances of 4-5 m, as is claimed for this module, unless you have a very specific, controlled environment that is free from objects that may confuse the sensor. I did confirm that it can measure distances down to about 20 mm, though it becomes critical to know precisely what the plane of the measurement is. I used the edge of the silver transducer enclosure, but the real transducer is buried inside. You may be able to calibrate that offset out, with some careful characterization.Check out the attached oscilloscope screen shot to see the basic operation of this module. It only needs 4 connections, VCC/GND for power, and a trigger pulse input, which produces an echo pulse output. The echo pulsewidth is proportional to the distance between the module and the object being ranged.The trigger pulsewidth does not seem to be critical, but it is specified to be 10 us minimum. I tried widths as low as 1 us and found that it worked reliably. At 500 ns, operation was intermittent. I would not recommend going below 10 us, per the datasheet. The 'scope photo shows a 1 ms trigger pulse. The echo pulse seems to consistently come 2.2 ms after the falling edge of the trigger pulse.The 'scope photo scenario was measuring a distance of about 280 mm. My setup was not intended to produce very accurate distances, but to show the operation over a range of distances. The resulting echo pulsewidth was averaging 1.616 ms, which given the formula in the datasheet, leads to a distance measurement of 275 mm, which seems reasonable.In my testing current consumption of the module was about 3 mA with a 5 V power supply.

This product is most easily used with a microcontroller that allows high-speed input and output of electrical signals. There are four wires that need to be hooked up to use it - two are power and ground, the other two are the trigger and the echo. This device works line sonar on a submarine. It sends out acoustic "pings" above the limits of human hearing under command, and then listens for the return from the reflection of the transmitted noise of of something in front of the sensor. Under program control of the microcontroller and with some simple math, the distance can be calculated.I used the Arduino NANO microcontroller to test (also available on Amazon for 9 USD) the sensors. The setup involved connecting 4 pins on a bread board, and then writing the code below:int TRIG = 14;int ECHO = 15;int DURATION;float DISTANCE;void setup() {pinMode(TRIG, OUTPUT);pinMode(ECHO, INPUT);Serial.begin(115200);}void loop() {digitalWrite(TRIG, HIGH);delay(1);digitalWrite(TRIG, LOW);DURATION = pulseIn(ECHO, HIGH);DISTANCE = DURATION / 58.2;Serial.println(DISTANCE);delay(200);}That's it! All of the action in the code is in the 7 lines inside the loop function. Send out a 1 millisecond pulse, measure the time until it returns, convert that time to distance. Easy Peasy.Here's the output of the program:14:37:38.571 -> 7.3414:37:38.803 -> 7.3414:37:39.001 -> 7.4214:37:39.200 -> 7.4214:37:39.432 -> 7.4214:37:39.631 -> 7.42For a total outlay of 12 bucks and a couple of minutes of assembly, this is an easy to use, absolute bargain of a solution. I should mention the build quality is great, and the silk screen is easy to use and interpret. Would buy again (but now I have 5!)

Good distance measure gadgets.Unfortunately, they are not covered or protected in any way, so it's difficult to use for outdoor purposes, and sometimes it gives bad readings, hence -1 point