total noob, first project waterproof ultrasonic water level detection

Hi all,

I'm a developer but a total noob to IoT/electronics, please help!

I'm looking to create something I can put on the inside of my water tank to monitor the water levels remotely, a colleague has done this and suggested using a JSN SR04T waterproof transducer, along with a WeMos D1 R2.

I notice that the transducer has an operating voltage of 5V yet the D1 operates at 3.3V. Would I be better off going for an Arduino Uno instead as that operates at 5V?

The device itself won't be near a power source or network point, so I'm looking for a board I can run via solar/battery, will also need wifi, can anyone suggest some options?

Not sure if this is too hard for a first project, but looking to start with something I can actually use and benefit from.

Thanks in advance :)

If the sensor operator 5 V like you say, then you either need to use a level shifter to shift the 3.3 V up to 5 V, or switch to the Uno.

The non-waterproof version of this sensor (HC-SR04) has 3.3V versions available. Fair chance the waterproof version does as well.

does anyone have link to 3.3V sensors?

I have just completed such a sensor.

I build sensors, some based on Wemos mini and others based on atmega328 + rfm95.

My tank level sensor is ATmega328 + rfm95 at 3.3V powered by 3xAAA batteries. No solar or WiFi available where the tank is.

I will dig out the link where I purchased the sensor for you.

Here it is.

Here is the last 24 hours data from the sensor. You can see where a bath was run at around 4pm yesterday and where I took a shower at 6am this morning.

I use the USB to power the WeMos with 5v and use 5v from the 5V output of the WeMos to power my JSN SR04T then just bring the signal into a pin on the WeMos.

Since the waterfproof versions are not usseable when the surface is closer than 9-10 inches, there is some need to distance the unit from the tank level. I read a post of other technologies, laser, I think, that would read closer objects.

as for putting 5 volt into the pins of the WeMos D1 -mini, I have a friend that knows a guy who was on a chat room where someone posted that there was a link to a site where a guy posted that he read a post where the CEO of Expresissive said that all pins on the ESP8266 are 5 volt tolerant. that was good enough for my project.

For mine (fuel oil) I use a 4 cell phone charger to I just plug it in to power the unit and remove the battery to charge it. I have not bothered with too much battery savings as the system is in deep sleep 99% of the time.

PaulRB, nice chart ! where/how is that hosted ?

dave-in-nj: PaulRB, nice chart ! where/how is that hosted ?

It's hosted on a commercial web server, the type you pay an annual fee of a ~£30 for and provides email, web space, database etc. I wanted to learn a little PHP, so I wrote my own scripts for storing & displaying data from a mySQL database and used SVG for displaying the graphs.

Thanks both of you!

Initially I bought the JSN SR04T but found it is very unstable and has many problems like minimum distance of 20cm

Thousands of others are having a problem with it too as per this video

Therefore JSN SR04T was a waste of money for me. Then I went onto choosing this other waterproof ultrasonic sensor.

It has lesser minimum distance of around 3cm because it has 2 transducers and is completely sealed from all sides.

Much better than JSN SR04T.