With the release of the new version of Arduover 4.1, it became possible to use HC-SR04. The principle of operation of the JS-SR04 is the same as that of the HC-SR04. I connected JS-SR04T, it works fine. The parameters are almost the same as the HC-SR04.
I compared the readings with the Mission Planner and the Laser rangefinder.
In the photo, they are directed at the ceiling in the room. This sensor can be used as a sonar, I will post the tests later.
JSR 04 T works great as an echo sounder, type in the youtube search “прикормочный кораблик глубиномер” you will see dozens of videos with examples in Russian the only one. These videos are self-made autopilots, with depth mapping on FlySky equipment only.
The speed of sound is different, but there you can change the coefficient to adjust for water.
i have done some testing and as i thought there is no easy way to change the scaling on a sr04 within ardupilot.I changed the sonar voltage scaling but it doesnt do anything it only effects analogue sonars thats why i was going to convert it to analogue. there was a backpack for the sr04 using a arduno that let the sr04 emulate a maxbotix i2c sonar but i cant find the code for it.
based on the data to the library, the values being taken are divided by 58. Apparently this is a coefficient for air. Since the speed in the air is about 320m/s and in the water 1450m / s, it is enough to change this coefficient(58). But I don’t own Github enough to do that
I found the code to convert one of these to analogue to be able to adjust it in ardurover as an analogue ratio. I also got my sr04 backpack, but im having issues with my JS-SR04 so I need to wait until I get another one before I can test it.
this might be a better option for boats, the control board is sealed
I am going to get one of these to test underwater, the dual transducer version can work at much shorter distances, im going to order one to see if it works better as a depth sounder in shallower water.
I found some other sensors that could be useful, the first one converts a sr04 to i2c, freeing up gpio pins and possibly allowing scaling in ardupilot. the second is an analogue version of the sr04 called the US-016, it would need the transducers swapped for water proof versions but it should work as it runs at the same 40khz and because its analogue it would support scaling in ardupilot.