DIY echosounder

I have to do a project in which I have to determine the nature of the seabed.

For that I need to make an echo sounder, but I don’t know if it’s really possible. I would only need to go to a depth of less than one meter.


have you tried a google search for DIY sonar?


Sonar... as used on boats. I'm sure there are sonar modules (don't bother trying to build that part yourself, it's not trivial) that can interface with microcontrollers.

Peterd51: have you tried a google search for DIY sonar?

Those don't work in water, and that's not because they're not waterproof.

You need to buy underwater sonar transducers. They are rather expensive and the driver circuitry is complex. Here is an entire project for DIY depth sounding, using a commercial sensor:

I have to determine the nature of the seabed.

Please explain what you must determine. But for one meter depth, why use sonar?

This inexpensive ultrasonic sensor, the DS1603L, may do what the OP needs and is easy to use with Arduino.

It is designed to measure the fluid depth in a tank and is intended to be adhered to the outside of the tank bottom surface. It works by sending ultrasonic pulses through the tank wall and measuring the time it takes for the pulses return to the sensor after being reflected by the fluid's top surface. Specs say it can measure 50 mm to 2000 mm (when used as intended).

However, @wvmarle has done at least one test holding the active side of the sensor just below the fluid surface and apparently gotten reasonable results. According to @wvmarle, "To test, you can hold the sensor in the liquid: active side just below the surface and you measure the distance to the bottom." and "it works when touching the water surface with the sensor"

@wvmarle also has a library for it.

The specs do not state the angular width of the ultrasonic "beam," a parameter that may be important for the OP's project. Or maybe not.

Ah, yes, that sensor should work for depth measurements. You should actually be able to glue it onto the bottom of a boat (as long as it's thin enough) and it will measure right through.

I have no idea how it will react to different sea floors. I've only played around with it in stainless steel tanks, which no doubt give very clean reflections.