I used ReefMaster for the first time today to create a map of a lake behind Sakamoto Dam near Karuizawa Japan. It's a pretty small but it's my first attempt and what I think is interesting is that I used ArduPilot (free open source drone software) to turn a Morey boogie board an EchoLogger.com ECT400 echosounder and a Pixhawk flight controller into an autonomous mapping boat.

I'm a software developer of ArduPilot and I'm not actually the first person in the community to do this. At least one other person has done it before me and I think I heard that he also uses ReefMaster. Anyway, I just wanted to share my success and make people aware that when it comes to the data collection part of making underwater maps, if you want to use an autonomous boat, there are inexpensive options available and I think they are complementary to ReefMaster.

This is cool. :)

Would moving the electronics box towards the front of the board or directly on top of the propellers make the board run more level?

If not, you may try tilting the transducer back a bit for the typical pitch to get a better return.

gpiversion,

Yes, it probably would and that might be better for these conditions (and mapping). We've used the same boat in strong rivers (not for mapping) and we found if the weight was too far forward that the nose would occasionally get caught by a wave and pushed under so we moved the weight back a bit.

This video doesn't show the nose going under but it shows the conditions where that was happening (before we moved the weight backwards)

rmackay9,
I'm curious about a few things on you configuration. Would you mind sharing some details?

What is the cost of the ECT400 unit? I have contacted the company but they still have yet to disclose a cost on the unit.

What is the frequency of the data that is logged? I'm interested in what the resolution could be and if it's configurable on ardupilot.

Is it possible to store large flash logs on a large storage drive. I don't have much experience with ardupilot but I have purchased a lot of components (pixhawk and etc) for a project much like yours.

If you want you can private message me.

Hi Yar,

I'm very happy to share!

I don't know the cost of the Echologger.com ECT400 because I got it in exchange for writing the ArduPilot driver but I hope they setup a webstore to make it easier for people to get them. By the way other NMEA echosounders also work with the new driver. A user here has gotten it working with a SonarMite SM4/BTX.

I set the sensor update rate to 2hz but up to 3hz is possible if the depth maximum is set to 100m. If the depth max is set lower (like 10m) the maximum rate is 10hz. The update rate is currently set by connecting to the sensor itself as described here. ArduPilot logs whenever the sensor provides an update. In the future it's possible we could make ArduPilot automatically configure the sensor but I'm not sure if/when we will do that.

Re large data - the next step is to store the "back scatter" data but that much data won't fit on the Pixhawk so we will attach the sonar to an RPi3 (or similar) and log it there along with the position data from the Pixhawk/ArduPilot (we will also send the simple depth to the Pixhawk/AP so you can see it on the ground station. When we do this we will extend "APSync" which is our recommended image for the RPI3 and this will make it easy for people to set it up (we have detailed instructions).

Hope that helps!

Awesome! I think what is most intriguing is the "low cost" title of this thread. I think this is great for the lower budget users like me.

I'm very interested in the resolution possibilities with both the 2hz and the 5 degree cone of the ECT400. I have a lake with sharp drop offs in mind.
Would you be able to help me with the raspberry pi connection?

Sorry again...novice user with lots of new hardware to play with.

Hi YAR,

Thanks for the feedback, Yes, low cost is great for everyone I think. It's cheap but it's still got a lot of features.

I haven't started on the RPi part of this yet. I hope to start on this in about a month..

Hi,

What is the model and specifications of the motors? I have been doing kind of similar experiments by using a trolling motor with 20 lbs thrust. The motor is OK and does not stop to the first weeds but steering with ArduPilot is bit hard because normal servo motors can't turn the trolling motor. Making a strong servo at reasonable price from an old windshield wiper motor and Arduino is possible but it is difficult to make the system to tolerate water and I have also considered to use two motors with skid steering as an easier and more reliable option.

With this link you find the thrusters used: www.bluerobotics.com/product-category/th...t100-t200-thrusters/