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Adding fathometer/depth finder to Blue ROV

(Roy Petter Dyrdahl Torgersen) #21

Yeah, we just got v0.3 in last week, but detected a minor problem with the power supply for the RPI3. I believe it has been fixed now, but I’ll double check. If the problem is solved and if we don’t need to redesign the board itself, we should be able to ship a few beta-units in mid september. I’ll check and get back with a price.

(Tim) #22

That would be fantastic, thank you. I’m still trying to figure out how to connect multiple accessories with the limited penetrators available. I have an extended battery tube with a 7-hole end cap to use as a junction box but the main tube is the problem. If the EnviroSense can send I2C, GPS, and sonar/NMEA over a single cable that will be a great solution.

(Roy Petter Dyrdahl Torgersen) #23

Yeah, that’s the whole purpose of the EnviroSense. I’ll send you some pictures of our setup tomorrow, but we are basically using a 2" tube as protection for the Atlas sensors, we have a 3" tube (cut short) for the echosounder, and then everything else is inside another 3" tube.

But I’ll send you a picture tomorrow.

(Tim) #24

Sounds good. I have a 2" tube on the way for the DT800, it looks like it will be a perfect fit with some minor mods. It will be fully enclosed with mineral oil bath and an acrylic end cap at the business end.

(Tim) #26

Hello Roy, any news?

(Drew Fulton) #27

Any updates on using an Airmar DT800? I’m intrigued about trying to encase it in its own tube with the sensor in water and then a plexiglass end cap. No idea if the sensor would work through the end cap or not. My current project is fairly shallow but the 10’ rating probably would be pretty close. Anybody?

(steven) #28

Hi Jacob,

Has there been any development on the pixhawk and NMEA 0183 integration? Thank you much!

(Drew Fulton) #29


I have hooked up a DT800 to the companion computer on the ROV via a USB serial connection. It is processing the NMEA0183 sentences and sending them out via pymavlnk. That’s the plan at least. I finalized the code yesterday but since I haven’t had the ROV in the water yet, I’m not actually getting any depth readings but the temperature sensor is at least working. I should have it in the water on Tuesday and can let you know if it works.

(steven) #30

Oh cool! Best of luck with that, I would love to know how it goes!

I am stuck right now with pixhawk for navigation, and arduino for GPS/sonar datalogging. If I could just use the pixhawk for everything, however, I would be so happy!

(Drew Fulton) #31

Hey Steven,

I’m sitting here poolside and got it working nicely. The sonar doesn’t particularly like my very reflective tiled pool and can get some wonky/noisy results if I’m moving quickly but I’ll do some work in the code on that and I should be good. Basically, it’s good to go! I think I’m going to build in a physical switch to my topside station that will start/stop the sonar logging so I can switch between depth hold and height hold. From what I can tell if there is sonar data available depth hold becomes height hold and nothing you can do about that. That’s what I’m seeing from my preliminary testing today.

(steven) #32

That is awesome! Good work. I just noticed that above you said you had a companion computer. What kind of computer are you using if you don’t mind? Did you have to invert the serial signal from the DT800? That was the only way I could read it on Arduino.

(Drew Fulton) #33

By companion computer I mean the raspberry pi companion that is already installled in the bluerov. And yes! I did have to flip the cables. Took me forever to figure that out. I was getting desperate and decided to try it as a last hope and it worked!

(Chris Geary) #34

I’d be careful repotting the transducer as it would need to be tuned to the transducer to match its frequency. This is known as the matching layer and is critical to the correct operation of the transducer. Matching layers need to be a set thickness above the element face and is critical to below a thousandth of an inch. It’s all about wavelength and velocity of sound in water.