ELEGOO5PCS HC-SR04 Ultrasonic Module Distance Sensor Compatible with Arduino UNO MEGA Nano Robot XBee ZigBee

Complete project description follows but the keys for the Ultrasonic Distance Sensor: 1) it's been running in a plastic box, outside, for almost a month with no problem. The Arduino wakes us every 15 minutes and takes a measurement, transmits it, then goes back to sleep. 2) it is measuring the distance TO WATER! I even turned the swim jets in my pool on to test turbulence and it works fine.Green Pond Bridge Boat ClearanceAt ‘very low tide’ the clearance under Green Pond Bridge in Cape Cod is 6’6” or less and that is too low for the boat I use. The tide charts for Falmouth, MA are theoretical and can vary as much as 18” from what is actually happening at the bridge. This system monitors the clearance and transmits the information on the internet.All of these parts were purchased from Amazon.TransmitterAn (Arduino) Elegoo UNO R3 board is connected to an Elegoo HC-SR04 Ultrasonic Distance Sensor. The UNO and the sensor calculate the distance from a fixed dock to the sea level, then transmit that data using a MakerFocus NRF24L01 Wireless Transceiver to the Receiver described below. The Transmitter sits on the end of a dock where there is no power, so the UNO, Transceiver and Distance Sensor are powered by the energyShield 2. This battery has special capabilities – it wakes everything up every 15 minutes. The system takes a couple readings of the distance to the water then transmits that data, then the battery shuts it all off. The data transmitted includes information from the battery – time, date, and voltage.I have been testing this unit at home (in Dallas) and it has been operating outside, for about 20 days. Based on battery drain it looks like it will operate for about 4-5 months before it needs a recharge. When the temperature drops below zero the system still works fine but the voltage reported in the battery seems low.All of this is housed in a plastic box printed for the purpose with a FlashForge 3d Printer Creator Pro, using eSun White ABS+ filamentPicture below.ReceiverAn (Arduino) Elegoo MEGA 2560 R3 is connected to another NRF24 Transceiver to receive the data. The MEGA does the math to convert the distance from the dock to the water, to the bridge clearance. Then the information is displayed on an Elegoo UNO R3 Touch Screen (that also works fine on the Mega).Picture below. A small plastic frame for the Receiver was also printed on the 3d printerWeb ServerFinally, the information in the MEGA is transmitted over a serial bus to a Hiletgo ESP8266 NodeMCU ESP-12E Internet WIFI Development Board (Also operates using Arduino IDE programming). This board is connected to the MEGA via the XCSOURCE Logic Level Converter and powered by a UCEC MB102 Breadboard Power Supply Module. All mounted on an Elegoo Breadboard. The ESP8266 is programmed to be a web server. It connects to the internet through the modem/router provided by AT&T.Picture of my cell phone below.

I was a little leery of these after buying several off-brand SR-04 sensors from another vendor a few years ago. I had constant trouble setting those sensors up, a google search revealed that there were known issues with the firmware in knockoff SR-04 sensors from that time period.Anyway, I received my Elegoo sensors yesterday, took one out of the bag and hooked it to a Raspberry Pi 3. It's working exactly as it should and I was able to get it running easily. Caveats on setting these up: 1) I think they use a significant amount of current, you may want to power the SR-04 separately from the Raspberry Pi power pins 2) the echo pin of the SR-04 produces a 5V pulse, so you'll need to set up a simple voltage divider to provide a 3V input to the Raspberry Pi. 3) One more reason to use Python 3 - time.perf_counter() will improve the precision of your pulse measurements!I think you'll be happy with these, have fun!

A nice plus are the Dupont wires provided. However the 5 sensors have a total of 20 connections. Yes there are 20 wires provided but 10 are female-male and 10 are female-female. It would be nicer if there were 20 of each since you want female-male to connect to breadboards.FYI, if you use them with the one wire (bidirectional) configuration and add a 74HC4051 mux/demux you can drive 8 of these with only four pins on the Arduino.

This product was used with Arduino UNO Board to have series of LED indicators set to descending distances to assist parking car in a residential garage. 5 red LEDs sequentially turn on until car is in correct location where a green LED turns on. Last LED is red again indication car has gone too far. This ultrasonic distance sensor works great and is very accurate. As now this prototype is working well, next a more consolidated version for esthetic appearance.

I like the price and the fact that they included some cabling. That is handy. I'd say the sensors from this vendor are about as good as any you'd find - average quality, but definitely not as bad as some!! I am starting to like Elegoo, as it seems they do a decent job of lowering prices, but keeping quality high enough to still be usable. So, from what I'm seeing, I think Elegoo is doing it right.

Easy to integrate with python on a Raspberry Pi. Seems to work well as a quick way to detect distance. Planning on using it to measure the water level in my sump pump to track changes and fill rates.

Great little sensor pack. Online docs made it easy to hook them up, they arrived quickly and as packaged on the store page pictures, came in a pack of 5. They do what they say they will at a reasonable accuracy and precision that I needed for a project.Note: I had one exposed to the elements for about 24 hours and it was no longer functional. Make sure to weatherproof them beforehand!

They work well.